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The Economic Aspect of Geology Flashcards

C. K. (Charles Kenneth) Leith · Public domain edition · 218 cards · 58 chapters

C. K. Leith argues that economic geology applies geological science to mineral resources and requires broad training in physiography, stratigraphy, and paleontology. The deck covers erosion cycles, rock composition and proportions, and why commercially important minerals are scarce in abundance tables.

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Chapter 1 · Question

What did the author say is required for professional preparation in economic geology?

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CHAPTER I4 cards

What did the author say is required for professional preparation in economic geology?
The author argues there is no easy short-cut: students who think a smattering of geological principles plus business knowledge suffices are mistaken. Analysis of professional successes shows economic geologists are most effective and in demand primarily because of proficiency in the science of geology itself, though business aptitude helps. One should first become a scientist, if only in a limited field.
Chapter 1
What is the erosion cycle, and what stages does it pass through?
Erosion by wind, water, and ice reduces land toward an approximate plain near sea level called a peneplain. When uplifted, erosion resumes: narrow steep valleys with broad uplands mark topographic youth; wider valleys leaving only points and ridges mark maturity; rounded, nearly flat surfaces mark old age, ending again in peneplain. Uplift may restart before base level is reached.
Chapter 1
How does physiography aid in reading underground structure?
The physiographer treats surface forms as stages in an orderly system, not heterogeneous units. A given structure may produce diverse topographic forms at different stages, so diversity may be only superficial. Conversely, a slight local divergence from usual forms may reflect a similar divergence in underground structure, suggesting important variations that would otherwise pass undiscovered.
Chapter 1
Why are stratigraphy and paleontology vital to economic geology?
Determining ages of strata and conditions of deposition is required in practice. Detailed knowledge of rock succession and ages, determined by fossils and other stratigraphic evidence, is vital to interpreting oil or coal fields and exploring their deposits. Certain iron ores, phosphates, salts, potash, and common rocks occur in sedimentary deposits and need stratigraphic and paleontologic knowledge for successful development.
Chapter 1

II. APPLICATION OF OTHER SCIENCES4 cards

What does the chapter say economic geology includes, in terms of man and environment?
The author argues that economic geology includes the consideration of man in reaction to his physical environment. He notes that some earth materials and conditions do not yet fall within the field, but so large a proportion do that the "complete economic geologist" should be almost omniscient. He adds that no individual can cover more than an insignificantly small portion of the field, so the title implies no mastery of it all.
Chapter 2
How does the chapter illustrate that new materials enter economic geology over time?
The author argues that requirements for earth materials differ by time and place: the Stone Age had little use for metals, while later ages broadened metal use. Modern demands, better metallurgy, chemistry, physics, transportation, and commercial organization bring new materials into use. He cites alumina, once little used except as an ornament, now in great demand as aluminum, with its raw materials intensively studied by economic geologists.
Chapter 2
What does the author say about the statistics and figures used in this volume?
The author states that somewhat generalized statistics are used to gain perspective, with no effort for detailed accuracy or completeness. Quantitative features are expressed in general proportions where possible, and specific figures indicate only such general proportions. He aimed not to be so specific that figures would soon be out of date. Standard statistical sources were drawn on, principally special investigations called out by the war in which he had a part.
Chapter 2
Why does the author draw illustrative cases mainly from the Lake Superior region?
The author explains that illustrative cases are often taken from his own field of experience, principally the Lake Superior region, though also the principal mineral deposits of North America, Cuba, and limited areas of South America and Europe. He acknowledges the Lake Superior iron and copper region may seem overemphasized relative to its importance, offers no apology, and argues an author's perspective is largely determined by training and experience. He suggests writers might confine discussion to matters within their own observation.
Chapter 2

CHAPTER II4 cards

What are the two main chemical types of igneous rock and their estimated proportions?
The author divides igneous rocks into (1) granite and allied rocks, rich in silica and therefore acid, light-colored gray and pink; and (2) basalt and allied types, lower in silica and higher in lime, magnesia, iron, soda and potassa, therefore basic, dark green and gray. The author cites an estimate that about 65 per cent of igneous rocks are granitic and 35 per cent basaltic.
Chapter 3
How do sedimentary rock mineral proportions differ from igneous, and why?
Sedimentary rocks, derived from destruction of igneous rocks, have less feldspar and ferro-magnesian minerals and more quartz and white mica, plus kaolin, dolomite, calcite, chlorite and limonite, which are nearly absent from unaltered igneous rocks. The author argues air and water constituents were added: carbon dioxide to lime and magnesia for calcite and dolomite, water to alumina and silica for kaolin, and oxygen and water to iron for limonite.
Chapter 3
In what proportions must shale, sandstone, and limestone form to match parent igneous rock?
The author calculates that sedimentary rocks must form as 82 per cent shale, 12 per cent sandstone, and 6 per cent limestone, since only this combination yields an average composition comparable with the parent igneous rocks. Field observation shows sandstones and limestones in relatively higher percentages, suggesting some shale was deposited in deep seas where unobservable, or was metamorphosed beyond recognition as shale.
Chapter 3
Why do commercially important minerals barely appear in abundance tables?
The author notes that of the abundant crustal minerals, only a few appear prominently in mineral resource tables: water and soils first, then common building and road rocks. Missing are most commercially important resources such as coal, oil, gas, iron ore, copper, gold and silver. The author argues these occur in relatively insignificant amounts compared with common rock minerals, despite great absolute bulk and commercial importance.
Chapter 3

CHAPTER III. SOME SALIENT FEATURES OF THE GEOLOGY4 cards

How does Leith classify mineral deposits formed directly from cooling magmas?
The author classifies mineral deposits as magmatic segregations in igneous rocks, formed as the magma cools and crystallizes. This is the first class in his scheme, followed by deposits formed immediately after crystallization through hot magmatic solutions, then secondary concentration, residual deposits, placers and sediments, and sedimentary deposits requiring further concentration.
Chapter 4
What evidence does Leith cite for an igneous source of ore deposits?
The chapter discusses evidence of igneous source for deposits formed immediately after the cooling and crystallization of magmas through hot magmatic solutions. It also considers the possible influence of meteoric waters in the deposition of ores of this class, and describes a zonal arrangement of minerals related to igneous rocks.
Chapter 4
What is the zonal arrangement of minerals related to igneous rocks?
Leith describes a zonal arrangement of minerals related to igneous rocks in connection with deposits formed after magma crystallization through hot magmatic solutions. The zones place different minerals at varying distances from the igneous source, a pattern the chapter treats as a salient feature of this class of deposits.
Chapter 4
How does Leith define anamorphism of mineral deposits?
The chapter includes anamorphism of mineral deposits as a topic in its classification scheme, listed after sedimentary deposits that required further concentration to become commercially available. The outline places it near the conclusion, treating it as a distinct category of change affecting mineral deposits within the overall classification.
Chapter 4

CHAPTER III (part 1)4 cards

Why does the economic geologist emphasize the origin of mineral deposits?
The author argues that knowing a deposit's origin answers practical questions: it lets explorers eliminate unpromising territory and concentrate on favorable localities, and it supports estimates of depth, form, value changes, and faulting. Different origins—hot waters versus surface waters, simple versus complex histories, presence or absence of secondary enrichment—lead to different expectations below the observed zone.
Chapter 5
Why are the terms primary and secondary problematic in economic geology?
They are merely relative, applying to a specific sequence rather than fixing an ore's absolute position. A sedimentary ore or placer derived from older ore may be called secondary, and a sulphide deposit may undergo successive enrichments, each secondary to the last but primary to the next. The author notes it is almost impossible to define them to cover all uses, though they remain useful in context.
Chapter 5
How does Ransome define hypogene, supergene, and protore?
Ransome proposed, especially for vein and contact deposits, hypogene ores formed by ascending non-oxidizing solutions, perhaps hot; supergene ores formed by oxidizing surface solutions, initially cold and moving downward; and protores, metallized rock too low in tenor to be ore but which would become ore had enrichment gone far enough. He defines primary ore as unenriched material that can be profitably mined.
Chapter 5
What features suggest the Sudbury nickel ores segregated within the norite magma?
The ores lie mainly within and along the lower margin of a norite intrusive, locally projecting into adjacent rocks. Their textures and intercrystallization with primary minerals suggest they were part of the norite mass, crystallizing during segregation before solidification. Nearby granitic rocks also appear to be segregations, locally replacing norite slightly later. Their absence from higher norite and distant rocks indicates segregation in place rather than outside solutions.
Chapter 5

CHAPTER III (part 2)4 cards

What evidence suggests ore solutions were hot and from deep magmatic sources?
The author lists several converging lines: quartz crystallized at high-temperature inversion points, fluid inclusions holding ferric oxide and abundant dissolved minerals, association with fluorine- and boron-bearing minerals and high-temperature silicates, occasional nearby hot springs, and ores lodged in inverted troughs. No single line is conclusive, but together the author argues they make a strong case for hot, deep, probably magmatic solutions.
Chapter 6
How does the author explain the possible role of meteoric waters in these deposits?
The author cautions against eliminating surface or meteoric ground-waters entirely. Igneous intrusions could heat such waters and drive vigorous circulation, letting them leach and concentrate disseminated ore over wide areas, as suggested for Kennecott, Alaska, and Ely, Nevada. At Goldfield, alunite is hard to explain except by surface oxidizing waters acting on hydrogen sulphide from below. The author thinks the two agencies may be inseparable.
Chapter 6
What is the zonal arrangement of ores around igneous rocks, and what exceptions exist?
Copper ores tend to lie closest to the igneous rock, with lead, zinc, and silver farther out, as at Bingham, Tintic, and Butte; in Cornwall, tin is near the intrusives and lead-silver farther away. Quartz gangue near the rock suggests hot solutions, while dolomite and calcite farther out suggest cooler conditions. The author stresses that gradations are not uniform and shoots may cut abruptly across zones.
Chapter 6
How are deposits classified by depth of formation, and what characterizes each zone?
Economic geologists sometimes classify deposits by deep, intermediate, and shallow depths of formation, though depth is only one factor determining intensity of conditions. Deep-zone deposits are associated with deeply eroded plutonic rocks, with gold, tin, iron, titanium, zinc, copper, and a quartz gangue bearing garnet, tourmaline, and mica. Shallow deposits relate to extrusive rocks and near-surface intrusives, with mercury, silver, gold, antimony, lead, zinc, alunite, adularia, and barite, often in calcite gangue.
Chapter 6

CHAPTER III (part 3)4 cards

What is the zone of secondary sulphide enrichment and how does it form?
It is the zone below the oxide zone, usually below the water table, where metals dissolved at the surface are redeposited as secondary sulphides. Copper, for example, is taken into solution as copper sulphate at the surface and redeposited as chalcocite on contact with chalcopyrite or pyrite. Sulphides of zinc, lead, silver and other metals are similarly concentrated in varying degrees. Ores mainly of secondary sulphides are called supergene ores.
Chapter 7
Why does the author question the importance of secondary sulphide enrichment?
The author argues that early enthusiasm magnified the process. At Butte, chalcocite occurs in solid masses proved to 3500 feet, far below the probable range of surface waters, so much of it is now considered primary; only certain sooty phases in upper levels are called secondary. At Kennecott, chalcocite with no traces of other primary minerals is regarded as probably primary. The author concludes it is not safe to assume the process in all camps.
Chapter 7
What are residual mineral deposits formed by weathering of igneous rocks in place?
When igneous rocks without mineral deposits weather, certain constituents are leached out and carried away, leaving others, as oxides and hydrates, in commercially available percentages. Examples include lateritic iron ores such as those of Cuba, many bauxite deposits, residual clays, and certain chromite and nickel deposits. Accumulation requires climatic and erosional conditions that keep the residue in place; in glaciated regions such deposits have usually been removed and dispersed in glacial drift.
Chapter 7
Why does the author say published descriptions of enrichment processes are often misleading?
The author argues that qualitative methods show the nature but not the quantitative range of processes. A mineral may be soluble and removed from the oxide zone and redeposited below, yet its actual distribution is often the reverse, because other materials dissolve and deposit faster. Quartz is insoluble compared with most minerals but more soluble than iron oxide, so surface concentration accumulates iron rather than silica. Reports may be correct that a process exists but mislead as to net results.
Chapter 7

CHAPTER III (part 4)3 cards

How does anamorphism affect iron ore versus coal, per the chapter?
The chapter contrasts Cuban iron ores, soft and cheaply mined at the surface with steam shovels, with the Cle Elum ores of Washington, apparently of similar origin but later buried and rendered hard and crystalline, requiring costly underground mining. Applied to coal, however, the same general anamorphic processes concentrate and improve grade, and likewise benefit oil up to a point, beyond which the oil may be lost.
Chapter 8
What three principal ways does the chapter say produce the main mineral values?
The author identifies three: (1) after effects of igneous intrusion, through aqueous and gaseous solutions given off from cooling magma; (2) sorting processes of sedimentation, the same processes forming sandstone, shale, and limestone, with organic agencies important; and (3) weathering of the rock surface in place, which concentrates values either by dissolving and redepositing valuable minerals or, more importantly, by dissolving out the non-valuable ones.
Chapter 8
What does the chapter say about why only some igneous rocks carry valuable minerals?
The author states that many granites are intruded into the outer shell of the earth, but only a few carry minerals, and of a series of intrusions in the same locality only one may carry valuable minerals. He says the minerals are somehow primarily segregated within the earth, but the causes are so involved with the problem of the earth's origin that no adequate explanation can yet be offered; discussion is beyond the book's scope.
Chapter 8

CHAPTER IV4 cards

What share of world annual mineral production does coal represent by tonnage and by value?
By weight, coal amounts to nearly 70 per cent of the world's annual crude mineral output of two billion short tons. By value, coal represents roughly 61 per cent of the approximately $9,000,000,000 annual world mineral value. The author notes these figures are rough generalizations meant to show perspective rather than precise detail.
Chapter 9
Why is mineral production concentrated around the North Atlantic basin, according to the author?
The author argues the concentration does not mean nature placed the deposits there. It expresses the localized application of energy to mineral resources by the people of that region. Applying the same energy elsewhere would essentially change the distribution. The controlling factors are historical, ethnological, and environmental conditions, not the amount of minerals in the ground.
Chapter 9
How does water compare with other mineral resources in tonnage and value?
Water counts as a mineral resource when used for drinking, washing, power, irrigation, and industry, though probably not for navigation, drainage, or as an excavation deterrent. Even narrowly interpreted, its extracted tonnage exceeds all other mineral resources combined. Its value is harder to state; as a physiologically indispensable resource the author calls its value in one sense infinite.
Chapter 9
What does the author conclude about world mineral reserves, and which commodities are exceptions?
The author argues reserves of the principal minerals are known to be ample, meaning sufficient to give no cause for worry for the next few decades, except oil, tin, and perhaps gold and silver. Present shortages may be temporary since much of the world remains unexplored. Every country is deficient in some minerals; the United States is best off but still lacks many.
Chapter 9

CHAPTER V3 cards

Why is water considered a mineral resource from a geological viewpoint?
The chapter argues water is a mineral—one of the most important—as well as a constituent of other minerals. It becomes a mineral resource when directly used by man. The author notes there is no satisfactory line between bottled 'mineral water' and general water supplies, since most serve the same purposes and none are free of mineral matter. Pumped municipal water is as much a mineral resource as bottled water.
Chapter 10
What is the zone of saturation and its upper boundary called?
Below the surface, at distances varying with climatic and topographic conditions, water saturates the openings of rocks, forming the zone of saturation or 'sea of underground water.' Its top surface is the water table or ground-water level. The space between the water table and the earth's surface is the vadose zone or zone of weathering, which is not necessarily dry and is not continuously and fully saturated.
Chapter 10
What essential conditions produce an artesian well?
The chapter states the essential condition for artesian circulation is a porous zone inclining downward from the surface beneath an impervious stratum that confines and ponds the water. Water in the bearing rock is under pressure roughly equivalent to the column determined by the height difference between that point and the feeding area. If the feeding area is higher than the well collar, water rises to the surface; capillary resistance usually lessens the theoretical pressure.
Chapter 10

Chapter V.4 cards

Why does the author say geology matters in tunnel planning and bidding?
The author argues that knowledge of rock and underground water conditions is needed in planning the work, in inviting bids, and in making bids, and during excavation. He states that too often in the past, disastrous physical and financial consequences resulted from ignoring elemental geologic conditions. He cites the New York aqueducts and subways, built through complex crystalline rock under close geological advice, where forecasts of rock kinds, water content, hardness, joints, and faults proved accurate.
Chapter 11
What did Chamberlin and Salisbury calculate about the strength of rock masses?
Chamberlin and Salisbury calculated that a mass of average hard rock a mile thick, domed to the curvature of the earth, can support a layer of only about ten feet of its own material. The author uses this to argue that the structural geologist, through studying folds, faults, and rock flowage, comes to regard rocks essentially as failing structures.
Chapter 11
What causes slides, and what factors may disturb equilibrium?
The cause of such movements is gravity. Disturbances of equilibrium may come from local loading, natural (unusual rainfall, raised water level, increased barometric pressure) or artificial (heavy buildings, dams). Movement may also follow excavation that removes lateral support, changes in moisture content, alterations of mineral and chemical character, or earthquakes. Wet slippery clay layers and planes of weakness such as bedding, joints, and cleavage localize movement.
Chapter 11
What did the Panama Canal experience reveal about drainage and soft rock?
The author argues that more attention to geology in the planning stages would have avoided mistakes at Panama, noting no strength tests of rocks were made early and no thorough study of slide factors. Only after slides became serious was geology intensively considered. The investigation found that certain soft rock formations were rendered weaker rather than stronger by draining off the water, contrary to the assumption that water acted as a lubricant rather than a cement.
Chapter 11

CHAPTER VI4 cards

What are the principal commercial factors determining availability of common rocks?
The author argues that because common rocks have bulk and low intrinsic value, transportation and ease of quarrying are the principal commercial factors in availability, though not the only ones. Mineral and chemical composition, texture, structure, durability, and behavior under pressure and temperature also matter, and their weighting depends on the intended use. The author warns that assuming availability without full technical investigation has ruined many building and quarrying ventures.
Chapter 12
What does the commercial term 'granite' include, and what are its main uses?
Commercially, granite includes true granite plus allied rocks such as syenite and gneiss, and sometimes even quartzite, though the author says calling quartzite granite goes too far. For statistics the USGS also included small amounts of diorite and gabbro. Its principal uses, roughly in order of importance, are monumental stone, building stone, crushed stone, paving, curbing, riprap, and rubble. Thirty states produce granite, led by Vermont, Massachusetts, and North Carolina.
Chapter 12
How does chalk differ from limestone in source and use in the US?
Chalk is a soft amorphous substance of the same composition as limestone. Its main uses are as a filler in rubber and as a component of paint and putty, and for polishing. England, Denmark, and France are the principal producers; the United States is the chief consumer and depends on imports for whiting, with no domestic chalk deposits commercially exploited. An inferior whiting can be made from waste fine limestone and marble quarry material.
Chapter 12
What are the principal uses of clay, and how did war affect imported clays?
Clays are used principally for building and paving brick and tile, sewer pipe, railroad ballast, road material, puddle, Portland cement, and pottery. High-grade clays were imported mainly from England for special purposes like paper coating, china, electrical porcelain, crucibles, and fillers. War experience showed domestic clays could substitute for most uses, but results were not always satisfactory, so the author expects imports to continue for some special purposes.
Chapter 12

CHAPTER VII4 cards

What three nutrients may soils lack, and what does cropping remove?
Soils may be originally deficient in nitrates, phosphates, or potash, and continued cropping removes these faster than natural weathering supplies them. A ton of wheat removes on average 47 pounds of nitrogen, 18 pounds of phosphoric acid, and 12 pounds of potash. The author notes most soils cannot keep pace with depletion from cropping, though some contain enough phosphate and potash indefinitely.
Chapter 13
What is the origin commonly believed for the Chilean nitrate beds?
The author states the origin is commonly believed similar to rock salt and other saline residues. Nitrogen probably came from organic matter such as guano, bones, and ancient vegetable matter; nitrifying bacteria formed nitrate salts, which were leached into enclosed basins, precipitated as waters evaporated, and concentrated around basin edges by deliquescence. The beds are essentially a product of desiccation.
Chapter 13
How is phosphate rock made available to plants, and what does that require?
The material mined is mainly tricalcium phosphate. To make it available for plant use it is treated with sulphuric acid to form soluble superphosphate, which is why sulphuric acid and its mineral sources, pyrite and sulphur, matter to the fertilizer industry. A small percentage is ground raw and applied directly to soil. Other phosphatic materials include Thomas slag, guano, and bone and tankage.
Chapter 13
How did war expose the world's dependence on Chilean nitrates?
The author states dependence on Chile became painfully apparent during the war. Germany alone had developed other nitrogen sources extensively; other nations relied heavily on mineral nitrates for fertilizer and munitions, and demand exceeded Chilean output, requiring international agreement on division. The nitrate shipping stream was a vital war artery, prompting fixation plants and by-product coke ovens, especially in the United States.
Chapter 13

CHAPTER VIII4 cards

What are the main uses of coal worldwide, and in what proportions?
The chapter states that roughly two-thirds of the world's coal is used for power, one-sixth for smelting and metallurgical industries, and one-sixth for heating purposes. Coal also makes up over one-third of United States railroad tonnage and is the largest single tonnage factor in international trade, with 70 per cent of pre-war outgoing cargoes from England being coal.
Chapter 14
Which countries lead world coal production, and in what shares?
The great coal-producing countries border the North Atlantic basin. The United States produces about 40 per cent of the world's total, Great Britain about 20 per cent, and Germany about 20 per cent. Others rank roughly: Austria-Hungary, France, Russia, Belgium, Japan, China, India, Canada, and New South Wales. The author notes these coal centers also host the major iron and steel industries.
Chapter 14
How are the world's coal reserves distributed by continent?
Estimates indicate North America holds about half of world reserves, principally in the United States with lesser amounts in Canada, and Asia about one-fourth, principally China with some in India. Europe holds only one-sixth, chiefly the former German Empire and Great Britain. Australasia, Africa, and South America together contain less than a tenth.
Chapter 14
What does the author argue about coal reserves and future industrial development?
The author argues that China's large reserves of high-grade coal may let it some day become a great manufacturing nation, since coal is a great base of modern industrialism. Conversely, he argues the coal deficiency of most South American and African countries seems to preclude large manufacturing industries there, except where water power is available.
Chapter 14

Chapter VIII).4 cards

What did Hoover's statistical study of metal mines find about depth and profit?
Hoover studied several hundred metal mines worldwide and found that not 6 per cent of profitable mines ever made profits from ore mined below 2,000 feet. Of mines that paid dividends, 80 per cent did not yield profit below 1,500 feet, and most died above 500 feet.
Chapter 15
How was the Swedish iron coefficient calculated and applied to estimate continental resources?
A Swedish geologist divided the known iron ore resources of comparatively well-investigated portions of the world by the number of square miles in which they occurred, then multiplied that coefficient into the area of continents whose resources were to be determined. The author notes such quantitative methods remain crude and partly disproved by experience.
Chapter 15
Why does the author argue that understanding ore origin is the geologist's most effective exploration tool?
The author argues that knowing the origin of an ore lets the geologist infer a whole group of practical considerations from experience with ores of like origin elsewhere. He contrasts this with the Cornishman's fatalistic dictum, 'Where it is, there it is,' and says origin is the geologist's distinctive tool, though he warns against dismissing practical observers' empirical facts.
Chapter 15
What percentage factors did Leith give for ore in the Mesabi and rest of Lake Superior iron formations?
Thirteen per cent of the productive area of the Mesabi iron formation is iron ore; for the remainder of the Lake Superior region the factor is five or six per cent. Leith says these averages suffice to pay large profits, but exploration is seldom large enough to hit the average, so geologic study aims to better the percentage.
Chapter 15

CHAPTER IX. MINERALS USED IN THE PRODUCTION OF3 cards

What technical and commercial factors determine which iron ore materials are used?
The chapter states that both technical and commercial factors determine the use of iron ore materials, treating these under economic features rather than geology alone. It separates economic features—technical and commercial factors, geographic distribution of production, and world reserves and future production—from geologic features such as sedimentary ores and ores associated with igneous rocks or weathering.
Chapter 16
How does the chapter classify iron ores by geologic origin?
The chapter organizes iron ores geologically into sedimentary iron ores; ores associated with igneous rocks; ores due to weathering of igneous rocks; and ores due to weathering of sulphide ores. These four categories appear as separate sections under geologic features, following the economic discussion of iron ores.
Chapter 16
What does the chapter say about world reserves and future iron ore production?
The chapter includes a section on world reserves and future production of iron ore, placed under economic features after the geographic distribution of iron ore production. It treats reserves and future output as an economic question, distinct from the geologic descriptions of sedimentary and igneous-associated ores that follow.
Chapter 16

CHAPTER IX (part 1)4 cards

What determines whether an iron ore is commercially usable beyond its iron percentage?
The author explains that iron percentage is only one factor: the mineral form matters (hematite ore is more valuable than magnetite with equivalent iron), and minor impurities such as phosphorus, sulphur, and titanium can make iron brittle, while excessive silica, lime, magnesia, or moisture may disqualify an ore. Acid and basic constituents can partly offset each other when balanced.
Chapter 17
How do steelmaking processes differ in the phosphorus content they allow?
The author states the acid Bessemer process is cheapest but needs very low-phosphorus ore (usually below .050 per cent in the United States, .030 per cent in England). Basic open-hearth, making two-thirds of U.S. steel, permits higher but not unlimited phosphorus. Basic Bessemer (Thomas) handles ore with any phosphorus over 1.5 per cent, and its phosphatic slag is used as fertilizer.
Chapter 17
Why does iron ore tend to move to coal regions rather than the reverse?
The author argues that throughout the industry's history iron ore has moved to coal-producing regions because the coal or energy factor ultimately controls. Coal underlies a great variety of interrelated industries for which iron ore is only one feeder, so it is not easy to relocate iron and steel production to ore sources where only iron and steel could be made.
Chapter 17
How self-sufficient is the United States in iron ore and ferro-alloy minerals?
The author says the United States is more nearly self-sufficing in iron ore than competitors, importing minor amounts mainly on a price basis; its one deficiency is extremely low-phosphorus ore, for which war experience showed dependence on foreign sources for 40 per cent or more of needs. For ferro-alloy minerals, however, it lacks adequate high-grade supplies except molybdenum, silica, magnesite, and fluorspar.
Chapter 17

CHAPTER IX (part 2)4 cards

According to the chapter, what determines the availability of iron ore?
The author argues availability is limited not by total reserves but by economic conditions. It depends on iron percentage, impurities, texture, mining conditions, furnace adaptability, distance from markets, transportation costs, relation to coal and fluxes, tariffs, taxes, and invested capital. Combined effect is expressed in cost of bringing the product to market, so cost comparison compares availability.
Chapter 18
How were the Lake Superior iron ores formed, according to the chapter?
They are residual deposits formed by weathering. Originally the iron was largely iron carbonate (siderite) and iron silicate (greenalite) interbanded with chert. Circulating surface waters leached silica, leaving less soluble hematite concentrated in a porous mass. Deep zones still show abundant siderite and greenalite, grading to hematite near the surface.
Chapter 18
What share of world iron ore production comes from sedimentary rocks?
Over 90 per cent of the world's iron ore production is from sedimentary rocks. These consist mainly of beds originally deposited as ore with little alteration, or enriched portions of lean ferruginous beds. A minor class is secondary replacement of limestones by iron-bearing surface waters. Bog ores are sedimentary hydrated iron oxide deposits in swamps and lakes, used only on a small scale.
Chapter 18
Why does the chapter say silica's solubility is often questioned?
The chapter notes silica solution on an immense scale has been questioned because silica minerals are often assumed insoluble. The author argues this assumption rests on the fact that most other minerals are more soluble than silica, so silica usually remains in weathering end-products. Iron oxide is even less soluble than silica, making silica leaching conspicuous when the two occur together.
Chapter 18

CHAPTER IX (part 3)4 cards

What are Cuban iron ores, in terms of their origin and relation to laterites?
The Cuban iron ores are similar in origin to laterites, which are surface accumulations of clay, bauxite, and iron oxide minerals from weathering of iron-bearing, commonly igneous, rocks. Typical laterites carry more clay and bauxite, but only because the original rocks carry more material that weathers to clay. The author states the Cuban iron ores are themselves, broadly speaking, laterites.
Chapter 19
What share of manganese consumption goes to steel, and how much manganese does a ton of US steel require?
Steel uses 95 per cent of total manganese consumed, while batteries and chemicals take 5 per cent. Manganese is added as spiegeleisen and ferromanganese to recarburize and purify molten steel after Bessemer converter and open-hearth treatment. On average each ton of steel in the United States requires 14 pounds of metallic manganese, equivalent to 40 pounds of manganese ore.
Chapter 19
How do low-grade and high-grade manganese ores differ in grade and in the alloys they make?
Low-grade ores, 10 to 35 per cent manganese, 20 to 35 per cent iron, and under 20 per cent silica, are used mainly for spiegeleisen (16 to 32 per cent manganese). Higher-grade ores, 35 to 55 per cent manganese, are used mainly for ferromanganese, in which manganese is 65 to 80 per cent of the total. Steel makers usually prefer ferromanganese; US ores as a whole are better adapted to spiegel.
Chapter 19
What happened to the US manganese industry when war shipping was released and foreign ore returned?
Larger offerings of foreign manganese ore and English ferromanganese arrived at prices domestic and Cuban ore and domestic alloy manufacture could not match. The result was a rather dramatic closing down of the manganese industry, with much financial loss, a bill reimbursing producers, and producer demands, though not consumer demands, for a protective tariff. The author argues geologists and engineers should understand these basic facts since they may be asked for advice on such policies.
Chapter 19

CHAPTER IX (part 4)4 cards

How does the garnierite (lateritic) type of nickel ore form, as at New Caledonia?
The original rock is a peridotite relatively low in nickel, altered to serpentine. Weathering concentrates the more resistant nickel at the expense of more soluble minerals, producing extensive blanket deposits of clay whose lower portions contain nickel in profitable amounts. Similar processes on somewhat different original material produced the nickel- and chrome-bearing iron ores of Cuba.
Chapter 20
What are tungsten's main uses and typical ore grades before and after concentration?
Tungsten is used chiefly in high-speed tool steels, added as powdered metal or as ferrotungsten (70 to 90 per cent tungsten). It is also used for incandescent lamp filaments, internal combustion engine contacts as a platinum substitute, and lately in airplane and automobile engine valves. Average grade of United States tungsten ores mined is less than 3 per cent metal; before smelting they are concentrated to about 60 per cent tungsten oxide.
Chapter 20
What geologic types host tungsten ores, and how important is secondary concentration?
Tungsten occurs mainly as scheelite, ferberite, huebnerite, and wolframite — relatively insoluble, high specific gravity minerals often accumulated in placers with cassiterite. Increasingly ore comes from primary deposits associated almost exclusively with granitic rocks, mostly veins and contact-metamorphic deposits in limestone near granitic borders, suggesting hot magmatic solutions. Tungsten minerals resist weathering; secondary concentration by surface chemical action has played no appreciable part.
Chapter 20
Where does vanadium come from and what are the origins of the Colorado-Utah deposits?
Two-thirds of world supply comes from Peru, mines under American control, with high-grade ore around 10 to 50 per cent oxide. United States low-grade ores run 1 to 8 per cent vanadium oxide. The Colorado-Utah deposits are large lens-shaped bodies of roscoelite in fissures and brecciated zones, replacing cementing material of flat-lying sandstones; origin is doubtful, generally supposed to be concentration by surface waters, though igneous dikes are also suggested.
Chapter 20

CHAPTER IX (part 5)4 cards

What two types of magnesite deposits does the chapter describe, and how do they differ?
The chapter describes magnesite deposits as lenses in dolomite, as in Austria, Washington, and Quebec, where magnesia-bearing solutions from nearby igneous rocks are believed to have replaced calcium carbonate with magnesium carbonate, yielding coarsely crystalline bodies worked by quarrying. The commoner type, in Greece, California, and Venezuela, consists of fine-grained veins and replacements in serpentine derived from altered peridotite, usually worked by open cuts.
Chapter 21
What purity standards must fluorspar meet for steel-making versus chemical and enameling uses?
For steel-making, fluorspar after concentration should contain at least 85 per cent calcium fluoride and less than 4 per cent silica. Chemical and enameling industries require material with 95 to 98 per cent calcium fluoride and less than 1 per cent silica. The chapter notes the United States has sufficient supplies for its own demands, and domestic fluorspar is superior to foreign for fluxing purposes.
Chapter 21
How does the chapter explain the origin of the large Illinois-Kentucky fluorspar deposits?
The chapter states that these deposits contain fluorite with calcite, barite, and metallic sulphides in wide veins filling fissures in limestones and sandstones and replacing the fissure walls. Peridotite dikes are intruded into these sediments, and the fluorite and associated minerals were probably deposited by hot solutions bringing material from a large underlying igneous mass, of which the dikes are offshoots.
Chapter 21
What roles does silica play in iron and steel manufacture, and what purity do silica refractories require?
Silicon is added to steel as ferrosilicon to deoxidize and purify the metal and increase tensile strength; the chapter says it is added chiefly for its curative effect rather than as a useful ingredient, averaging 4 pounds of 50 to 55 per cent ferrosilicon per ton of steel in the United States. Silica brick or ganister lines furnaces with acid slags, and the rock should contain 96 per cent or more silica with little alkali material.
Chapter 21

CHAPTER X (part 1)4 cards

What are the main uses and consumers of copper according to the chapter?
The electrical industry is the largest consumer of copper. Brass, bronze, and other copper alloys form another chief use. Copper sheets, tubes, and wares are used in roofing, plumbing, and ship bottoms. Copper is also used in coinage, particularly in China, where it is the money standard of the working population.
Chapter 22
What is the average grade of copper ore mined in the United States, and how does ore grade affect processing?
The average grade of all United States copper ores in recent years has been about 1.7 per cent metallic copper. Ores as low as 0.6 per cent have been mined in the Lake Superior country, while bonanza deposits of 20 to 60 per cent were worked in Alaska and Wyoming. Lower-grade ores of 1 to 3 per cent are usually concentrated before smelting; richer ores of 3 to 5 per cent or more are generally smelted direct.
Chapter 22
How does the United States compare with other nations in copper production and control?
The United States normally produces nearly two-thirds of the world's copper but consumes only about one-third. Much South American, Mexican, and Canadian crude copper comes to the United States for refining. Through foreign financial interests and refining facilities, the United States controls about 70 per cent of world copper. No other country produces one-sixth as much copper as the United States.
Chapter 22
What are the principal copper minerals and their relative contributions to supply?
Copper minerals fall into sulphide, oxide, and native copper groups. Native copper from the Lake Superior region supplies 8 to 10 per cent of world copper. The oxide group, including azurite, malachite, chrysocolla, cuprite, and associated native copper, supplies about 5 per cent. The remaining 85 per cent comes from sulphides, with chalcocite the most important, plus enargite, chalcopyrite, bornite, tetrahedrite, and covellite.
Chapter 22

CHAPTER X (part 2)4 cards

What evidence suggests some copper deposits formed during sedimentation of enclosing beds?
The chapter lists close limitation of copper to certain beds, wide and uniform distribution within them, absence in similar nearby beds, absence of feeding and escape channels needed for later solutions, and minute participation of copper minerals in bedding, false-bedding, and ripple-marks—features hard to explain by secondary concentration.
Chapter 23
How does the chapter describe the downward zones in sulphide copper deposits?
First a weathered zone, originally mainly above the water table, with a leached portion above and oxides and carbonates of copper below; second a zone of secondary sulphide enrichment with chalcocite coatings, chalcopyrite, and pyrite; third a zone of primary deposition with chalcopyrite, and at Butte enargite and chalcocite.
Chapter 23
What does the chapter say about the cyclic nature of secondary enrichment?
The author argues enrichment is probably cyclic rather than continuously progressive. As chalcocite increases, enrichment slows and erosion may overtake it; removal of part of the protecting chalcocite zone re-exposes protore to oxidation and a second cycle begins. Enrichment is believed to have occurred mainly above any general water table.
Chapter 23
What two general classes of lead ores does the chapter distinguish?
First, 'soft' lead ores nearly free of copper and precious metals, commonly with zinc, in sedimentary beds independent of igneous intrusion—worldwide, first exploited, now about 30 percent of world output. Second, complex ores associated with igneous rocks, often containing zinc, silver, gold, copper and others, now about 70 percent of world lead.
Chapter 23

CHAPTER X (part 3)4 cards

How did the German Zinc Syndicate control the world zinc market before the war?
The chapter states the German Zinc Syndicate controlled directly one-half of world zinc output and three-fourths of European production through affiliations, joint share-holdings, ownership of mines and smelters, and especially smelting and selling contracts. It regulated Australian exports by long-term contracts and had considerable influence in the United States, sometimes manipulating the market so zinc outside the syndicate was indirectly controlled.
Chapter 24
What are the two general classes of zinc ores described in the chapter?
First-type ores are veins and replacements in sedimentary rocks at shallow depths, independent of igneous association, supposedly formed by cold solutions; found in the Mississippi Valley, Silesia, and smaller European deposits, now about 45 percent of world output. Second-type ores are veins and replacements related to intrusive rocks, sometimes deep and more complex, including most American Cordilleran deposits, Franklin Furnace, Australia, and Burma.
Chapter 24
What does the author conclude about the origin of Mississippi Valley zinc-lead ores?
The author argues the evidence favors accumulation by downward-moving meteoric solutions during weathering of overlying strata, though it is by no means certain part of the ores was not derived from lower horizons. He cites the broad area versus shallow depth, ore association with the surface regardless of horizon, failure of ores under later cappings, and oxidizing waters' known efficacy in downward zinc and lead transfer.
Chapter 24
Why does the author doubt secondary sulphide enrichment formed most of the sulphide zone values?
He reasons that if downward secondary enrichment were dominant, ores should be richer where erosion cut away more than half the ore-bearing limestone than where it barely cut into the formation. This is not the fact, suggesting erosion carried much of the zinc completely out of the vicinity. Evidences of secondary enrichment exist, but broad quantitative considerations raise doubt.
Chapter 24

CHAPTER XI (part 1)3 cards

What is gold's principal and most essential use, and what backs modern currency?
The author states gold's principal use is as a standard of value and medium of exchange. Little metal actually circulates by hand; instead, government and banking stocks of gold form the essential foundation of paper currency and the modern credit system. Gold also moves between nations to settle international trade balances, though such shipments are great in value but very small in volume.
Chapter 25
Why did world gold production decline during and after the war?
The author attributes the decline largely to the fixed price of gold and wartime restrictions limiting its use to monetary purposes. Unlike iron and copper, gold's price could not rise to offset growing mining costs, shrinking profit margins and discouraging exploration and production. Exhaustion of certain mines, lower ore grades, and lack of new discoveries also contributed.
Chapter 25
Why was a gold bonus denied to miners, and what did it cost?
The author reports wartime bonus demands in the United States and South Africa were denied over doubt the measure would work and fear of upsetting the gold standard. A requested $10-per-ounce bonus seemed unlikely to raise United States output more than 10 percent, and paying it on all gold mined meant gaining ten million dollars would cost about forty million.
Chapter 25

CHAPTER XI (part 2)4 cards

What did the Pittman Silver Act of April 1918 authorize?
It authorized melting down and converting into bullion 350,000,000 dollars of silver dollars from the Treasury stock, retiring a corresponding number of silver certificates and issuing Federal Reserve bank notes. The silver used for exchange and export was to be replaced by buying bullion from American producers at $1 per ounce and coining it into new dollars, establishing a minimum price of $1 per ounce.
Chapter 26
How is world silver production split between primary ores and by-products?
About half of world silver production comes from dry or siliceous silver ores mined solely for silver and associated gold. The other half is obtained as a by-product in mining other metals, principally copper and lead. Because the silver percentage in any copper or lead mine is ordinarily very small, the world silver output depends considerably on conditions in the copper- and lead-mining industries.
Chapter 26
What are the most important silver minerals, and how does silver differ from gold chemically?
The most important silver mineral is the sulphide argentite, or "silver glance." Others include silver-antimony sulphides (pyrargyrite, stephanite, polybasite), silver-arsenic sulphides (proustite, pearcite), and the silver antimonide dyscrasite. In the oxide zone, cerargyrite (silver chloride) and native or "horn" silver are most abundant. Silver differs from gold in being chemically active and forming many stable compounds.
Chapter 26
What origin does the chapter give for the Cobalt, Ontario silver ores?
The ore minerals are believed to have been deposited by hot solutions from deep magmatic sources after the intrusion of the diabase. The silver minerals are distinctly later than the cobalt and nickel in the unoxidized zone, as seen under the microscope. This, plus abundant native silver in the shallow oxide zone, suggested downward concentration by surface waters, but recent studies indicate some silver at least was deposited by later ascending magmatic solutions.
Chapter 26

CHAPTER XI (part 3)3 cards

From what type of deposit has over 99 percent of world platinum production come?
Over 99 percent of world platinum production has been derived from placers—small grains and scales in stream and beach deposits. Examples include the Ural Mountain gold- and platinum-bearing placers of Russia, which drain dunite rock, plus placers in Colombia and Australasia. In the United States, small quantities come from gold-bearing gravels in California and Oregon whose streams drain serpentine and peridotite areas.
Chapter 27
Where is sperrylite found, and how is it concentrated at Sudbury?
Sperrylite, a platinum arsenide, is sometimes found with sulphide minerals in basic igneous rocks. At Sudbury, Ontario, it occurs with palladium arsenide in the nickel ores, especially in the weathered zone, where it is concentrated by removal of more soluble materials. It has also been found in the copper mines of Rambler, Wyoming.
Chapter 27
What is unusual about the Yellow Pine district platinum deposit?
In the Yellow Pine district of southern Nevada, metallic gold-platinum-palladium ore shoots occur with copper and lead ores in a fine-grained quartz mass replacing limestone beds near a granitic dike. No basic intrusives are known there. The deposit is unusual for its high platinum content, nearly an ounce to the ton, and is probably genetically related to acid intrusives.
Chapter 27

CHAPTER XII (part 1)4 cards

What impurities affect bauxite's commercial grade and use?
Bauxite deposits usually contain silica (as kaolin or hydrous aluminum silicate), iron oxide, and titanium minerals as impurities. Commercial-grade bauxite should carry at least 50 percent alumina. For aluminum making it should be low in silica though iron may be fairly high; for chemicals low iron and titanium are preferred; refractories need low iron; the abrasive trade generally uses low-silica, high-iron bauxites.
Chapter 28
How do bauxite deposits generally form, and what is lateritic alteration?
Bauxite forms by extreme surface weathering (katamorphic processes) of rocks high in alumina and low in iron and quartz. Ordinary weathering leaves kaolin, quartz, and iron oxide; under tropical conditions the kaolin breaks up, silica dissolves and is carried away, and hydrous aluminum oxides remain as bauxite. This extreme weathering is sometimes called lateritic alteration.
Chapter 28
What are the principal uses of antimony and its alloys?
Antimony is used mainly for alloying. Over one-third of United States consumption goes into babbitt or bearing metal alloyed with tin and copper. Other alloys include type-metal (lead, antimony, tin), which expands on solidification; hard lead for acid-resisting valves; Britannia metal for cheap tableware; plus solders, brasses, bronzes, and battery materials. Oxides serve in enameling, glass coloring, and pigments; red sulphides in rubber and matches.
Chapter 28
Which countries dominated antimony production and smelting before and during the war?
China was by far the most important producer, normally supplying over half the world's total, exporting crude sulphide and regulus about 99 percent pure. France was the only other important source (25 to 30 percent), with small amounts from Mexico and Hungary. Before the war antimony was smelted chiefly in China, England, and France; London was the principal market. The war brought output from Algeria, Bolivia, and Australia.
Chapter 28

CHAPTER XII (part 2)3 cards

What is greenockite, and how do greenockite coatings form on sphalerite?
Greenockite is cadmium sulphide, nearly the only known cadmium mineral, though no deposits are large enough to be called cadmium ores. Coatings on sphalerite in cavities probably formed by decomposition of cadmium-bearing zinc sulphide in the oxide zone, cadmium carried down in solution, and precipitated as secondary cadmium sulphide.
Chapter 29
Which countries dominate world mercury production, and who controls the market?
The large producers, in normal order of importance, are Spain, Italy, Austria, and the United States. Spain's Almaden mines are government-owned, with output sold through the Rothschilds of London. England largely controls the European commercial situation, and London is the world's great quicksilver market where prices are fixed.
Chapter 29
What are the principal cobalt minerals, and what do they weather into?
The principal cobalt minerals are smaltite (cobalt arsenide), cobaltite (cobalt-arsenic sulphide), and linnaeite (cobalt-nickel sulphide). Under weathering they oxidize readily to form asbolite, a mixture of cobalt and manganese oxides, and the pink arsenate erythrite, or 'cobalt bloom.' Cobalt minerals occur mainly in small quantities disseminated through silver, nickel, and copper ores.
Chapter 29

CHAPTER XII (part 3)4 cards

What are the two principal tin ore minerals and how does tin occur in deposits?
Cassiterite (tin oxide) is the principal tin mineral; stannite, a sulphide of copper, iron, and tin, occurs in some Bolivian deposits but is rare elsewhere. About two-thirds of world tin comes from placers and one-third from vein or lode deposits; over 90 per cent of tin in southeastern Asia and Oceania comes from placers.
Chapter 30
How do cassiterite veins form, and what is their relation to granitic rocks?
Cassiterite veins are universally associated with granitic rocks, and their origin is evidently related to igneous intrusions. Their occurrence in fissures in granite and the surrounding contact-metamorphic zone indicates the granite had consolidated first, representing a late cooling stage. Fluorine- and boron-bearing minerals and intense wall-rock alteration suggest very high temperatures, possibly gaseous "pneumatolytic" conditions, though the chapter says evidence is not available to decide.
Chapter 30
What are the principal uranium and radium minerals and where are the important deposits?
Carnotite (hydrous potassium-uranium vanadate) and pitchblende or uraninite (uranium oxide) are the principal sources. Joachimsthal, Bohemia, has pitchblende with silver, nickel, and cobalt in veins associated with igneous intrusions. The important Colorado and Utah deposits contain carnotite with roscoelite as impregnations of flat-lying Jurassic sandstones.
Chapter 30
What is the maximum radium content of uranium ore, and how do Colorado-Utah carnotite ores form?
Radium occurs only in uranium ores, in exceedingly small quantities; the maximum in equilibrium is about one part radium in 3,000,000 parts uranium. The carnotite ores are supposed to have been derived from clays and impure sandstones a few hundred feet above, carried downward by sulphate-bearing surface waters. Association with fossil wood and carbonaceous material suggests organic matter aided precipitation, but the exact process is unclear.
Chapter 30

CHAPTER XIII (part 1)3 cards

What is the chief ingredient of most natural abrasives used in the US?
Silica or quartz in its various crystalline forms constitutes over three-fourths of the tonnage of natural abrasives used in the United States. It is the chief ingredient of sand, sandstone, quartzite, chert, diatomaceous earth, and tripoli, from which millstones, grindstones, hones, sandpaper, and other abrasive products are made.
Chapter 31
How does the chapter explain the origin of asbestos veinlets in serpentine?
Asbestos deposits occur chiefly as veinlets in serpentine rock, formed in cracks and fissures through the agency of water, though whether hot or cold is not apparent. The veinlets were sometimes interpreted as fillings of contraction cracks, but the author argues they are more probably due to recrystallization of the serpentine proceeding inward from the cracks.
Chapter 31
What are the principal uses and sources of barite?
Barite is used chiefly in paints, both ground and in manufacturing lithopone, a white paint of barium sulphate and zinc sulphide. It also goes into rubber goods, heavy glazed paper, and barium chemicals. Germany is the world's principal producer with large high-grade reserves; before the war the US imported nearly half its barite from Germany, but wartime needs developed adequate domestic supplies.
Chapter 31

CHAPTER XIII (part 2)4 cards

What are the main industrial uses of bromine described in the chapter?
Bromine is used in chemistry as an oxidizing agent, in separating gold from other metals, and in making disinfectants, bromine salts, and aniline colors. Silver bromide is used in photography and potassium bromide in medicine to depress the nervous system. During the war, large quantities were used in asphyxiating and lachrymating gases.
Chapter 32
Where does the United States obtain its bromine, and how is it produced?
The entire domestic tonnage is produced from brines pumped in Michigan, Ohio, West Virginia, and Pennsylvania, making the U.S. independent of foreign sources. Much of the output is marketed as potassium and sodium bromides rather than pure bromine. It is produced as a by-product of the salt industry, with bromides extracted from mother liquors or directly from unconcentrated brines.
Chapter 32
Why can't chemical analysis determine whether a clay will work as fuller's earth?
Fuller's earth is essentially a clay with high absorptive power used for decolorizing and purifying. The chapter states that fuller's earths vary widely in physical and chemical properties, and chemical analyses are of little value in determining suitability; an actual test is the only trustworthy criterion. Deposits occur under the same variety of conditions as other clays.
Chapter 32
What quality of graphite do crucibles require, and which sources supply it?
Crucibles require coarsely crystalline graphite. The largest production of high-grade crucible graphite has come from Ceylon, under British control, with about two-thirds going to the United States. Madagascar provides a rival supply with large reserves and cheaper production, though its flake quality differs and has not found favor in the U.S. but suits European crucible makers.
Chapter 32

CHAPTER XIII (part 3)4 cards

Why can't mica mining be organized on a large scale?
The author explains that mica distribution within dikes is erratic, making reserve predictions hazardous; associated quartz and feldspar exceed the mica, and individual deposits are likely small. Mining is therefore hand-to-mouth near the surface, relying on much hand labor, with output coming from many small mines rather than one large one.
Chapter 33
How is monazite recovered commercially, and what is its thorium content?
Monazite is a phosphate of cerium, lanthanum, thorium, and other rare earths; thorium oxide ranges from a trace to 30 percent, with commercial sands usually mixed to at least 5 percent. Though crystals occur in granites, gneisses, and pegmatites, the author states it is recovered commercially only from placers, concentrated with zircon, garnet, and ilmenite.
Chapter 33
What qualities give a precious stone value, according to the author?
The author argues value comes from beauty, endurance, and rarity, or some combination that catches the popular fancy. No single quality suffices, and possessing all does not insure value: some rare, beautiful stones are known only to collectors, while whim and chance influence demand. Value thus has both intrinsic and extrinsic elements.
Chapter 33
Where do most of the world's diamonds come from, and how are they extracted?
Most diamonds come from the Kimberley and Transvaal fields of South Africa, found in decomposed volcanic 'blue ground,' originally peridotite in volcanic necks penetrating carbonaceous sediments. Mined rock decomposes over six months to a year, then is washed and sorted. The author notes a large mine's annual diamonds could fit in a large suit-case.
Chapter 33

CHAPTER XIII (part 4)4 cards

Why is the thickness of salt beds a puzzling geologic problem?
Salt deposited from a given volume of sea water is so small that forming 500 feet of salt over an area would require an equivalent area of water 25,000 feet deep. Explaining such thick beds therefore requires special physical conditions, which geologists have proposed various theories to supply.
Chapter 34
How does the 'bar' theory explain thick salt deposits?
The bar theory suggests deposition occurred in a bay separated from the sea by a bar. Sea water flowed in over the bar or through a narrow channel, balancing evaporation in the bay, so salts from a very large quantity of sea water accumulated in a small bay. Progressive concentration precipitated salts in great thickness, and final separation could cause complete desiccation and potash-magnesium salts like those at Stassfurt.
Chapter 34
How does salt's plasticity affect the thickness of salt beds?
Salt beds, especially when soaked with water, are highly plastic and incompetent under pressure. During deformation of enclosing rocks, salt flows somewhat like a viscous liquid, becoming thinned on the limbs of folds and correspondingly thickened on the crests and troughs. This partially explains some great thicknesses found in salt beds.
Chapter 34
What is the debated origin of the Gulf Coast salt domes?
The domes occur in Tertiary and more recent sands, limestones, and clays, with vertical salt thicknesses of a few thousand feet known only from drilling; some contain petroleum, gypsum, and sulphur, and no igneous rocks are known nearby. Some thought hot waters from underlying igneous rocks formed them, with upbowing attributed to growing crystals, hydrostatic pressure, or laccolithic intrusions. Others suggest a sedimentary origin later modified by deformation and alteration. The origin remains uncertain.
Chapter 34

CHAPTER XIV (part 1)4 cards

Why does the author say the geologist is not superfluous despite discoveries made without geology?
The author argues that there are often hundreds of "practical" explorers to one geologist, so in proportion to numbers the record differs greatly. He notes many large mining organizations now leave exploration and development largely to geologists, and that not all geology is applied by geologists—prospectors absorb elements empirically. He also says geological advice, in proportion to scale of use, has had more than its share of success.
Chapter 36
What advantage does the author claim for exploring older districts over virgin territory?
The author argues the economic geologist stands at least as good a chance in older districts as in new fields. In a producing district the geologic conditions are proved right, giving a pragmatic advantage, and much essential information can be built into the plan—the explorer starts where others left off. He cites one geologist who said more previous work means more tools, and denies any "skimming the cream" from a geologic problem.
Chapter 36
What common tendency does the author warn against regarding prior information in exploration?
The author warns against going into a field unprepared with thorough knowledge of preceding work. Explorers easily forget or dismiss old investigations as out of date, and younger generations often ignore older reports, rediscovering elementary truths after large efforts that proper study of previous literature and mapping could have saved. He recommends searching U.S. Geological Survey, Bureau of Mines, state survey, university, and technical society reports.
Chapter 36
What does the author say about cooperation and drill records in exploration?
The author argues competition breeds suspicion and furtiveness unfavorable to cooperation, and playing a lone hand handicaps explorers. He says public registration of all drilling records is highly desirable, avoiding duplication, since even a barren hole may matter greatly later. Property rights can be protected by withholding records until the explorer has time to use them. He cites Illinois Survey direction of Trenton limestone oil exploration financed by private capital.
Chapter 36

CHAPTER XIV (part 2)4 cards

What must be shown about lands in building-stone, petroleum, or salt placers?
Such lands must be more valuable for those minerals than for any other purpose. More broadly, the chapter says the whole scheme of American land laws requires determining the use for which each tract is best fitted, and the Geological Survey has classified coal, oil and gas, phosphate, potash, metalliferous, and other lands to support that determination.
Chapter 37
Why do many mineral deposits fail to outcrop at the surface?
Deposits may be covered by weathered rock or soil, glacial deposits, or younger formations such as surface igneous flows or sediments. Their outcrop may also be so altered by weathering that it gives little clue. The author argues that far more deposits are covered than exposed, and that by far the greater part of the earth's mineral wealth may never be found.
Chapter 37
How does gossan form, and what does it indicate?
Iron sulphide in sulphide ore bodies oxidizes to limonite at the surface, producing iron-stained rocks called gossan, iron capping, colorado, or eiserner Hut. The gossan resists erosion and is often conspicuous, though it rarely carries much value; it may show traces suggesting what lies below. Gold, silver, and lead resist leaching, while copper and zinc leach readily and may show only staining.
Chapter 37
How can placers help locate the source of ore deposits?
Ore fragments in placers, mountain-side wash, or glacial deposits raise the question of origin. For recent placers, one can follow stream channels to the headwater area delivering most sediment, then locate the vein. Multiplicity of tributaries and large drainage areas complicate this, so careful panning and testing of gravels at frequent intervals can show which tributaries contribute most values.
Chapter 37

CHAPTER XIV (part 3)4 cards

For which types of mineral deposits is drilling most useful in exploration?
Drilling is more useful for locating and proving deposits of large bulk, such as coal, iron, and oil, than for deposits of small bulk and high value, like gold and silver. The chapter notes, however, that drilling is not always used for the first class and not always eliminated for the second, and its use is rapidly extending as equipment and interpretation improve.
Chapter 38
What roles does the geologist play in drilling operations?
The geologist locates the drill holes, determines their angle, identifies and interprets samples, studies bedding, cleavage, and other structures shown in samples and determines their attitude underground, decides when the most promising horizon is reached, and determines when the hole shall be stopped. The chapter stresses that faulty reasoning or over-emphasis on any one factor can cause failure or extra expense.
Chapter 38
Why is a three-dimensional conception of underground structure important in drilling?
The chapter states that locating and directing a drill hole for maximum results requires careful consideration of many geologic factors arranged in proper perspective and relationship. Faulty reasoning from any one principal factor, over-emphasis on one of them, or failure to develop an accurate three-dimensional conception of underground structural conditions may lead to failure or extra expense, and success or failure is swiftly and definitely determined.
Chapter 38
How are quantitative methods used in geologic exploration?
The chapter notes a recent tendency to reduce geologic factors in exploration to a quantitative basis, since their net effect can often be expressed as quantitative averages. Local quantitative factors worked out in wide-extent mines and districts help predict results of proposed explorations in undeveloped portions, and can guide planning, cost, and probable outcome. Oil production curves also share characteristic features used to predict future output and life.
Chapter 38

CHAPTER XV4 cards

What two elements make up the value of a mineral deposit?
The value of a mineral deposit comprises an intrinsic element based on the qualities of the material itself and an extrinsic element based on its availability and the nature of demand for it. Neither exists without the other. Identical deposits may differ greatly in value due to distance from markets, transportation, or the methods available for use. The author summarizes this as man being the multiplier and the mineral substance the multiplicand in value.
Chapter 39
Why are mineral deposits in the ground rarely valued by market transfers?
Mineral deposits in the ground are not bought and sold frequently enough on the open market to establish standard market values. A sale may set a criterion for that particular deposit but not for the class, since no two mineral deposits are exactly alike. Stock quotations may establish a kind of market value, but these are often vitiated by extraneous considerations, so valuation is a special problem in each case.
Chapter 39
How does the ad valorem method compute present value of a deposit?
The ad valorem or rational method multiplies profit per ton by total estimated tonnage, including known, probable, and sometimes possible reserves, to get total net receipts. Because ore is extracted over years, each annual payment must be discounted to present worth, requiring an estimate of the property's life and rate of depletion. In the chapter's example, $1,000,000 received in ten annual instalments at 8% has a present value of $612,000.
Chapter 39
How is the interest rate chosen in mineral valuation?
The interest rate is a financial matter, but the geologist must consider it because the rate must vary with the degree of hazard and doubt in geologic factors. Where ore reserves are doubtful, a high rate is used to allow for that hazard; a large, well-developed deposit with known geology and established markets justifies a lower rate. In practice rates vary from 6 to 15 or 20 per cent.
Chapter 39

CHAPTER XVI4 cards

What two conflicting considerations underlie mining laws on the public domain?
The chapter says these laws rest on two partly conflicting ideas: that wasting mineral resources accumulated over long geologic periods are peculiarly public property, a heritage for the people; and that discovery and development require a free field for individual initiative, since governments are generally neither greatly interested nor particularly successful in exploration.
Chapter 40
How do US mining laws on public domain compare with South Africa, Australia, South America?
The author states that in the United States the laws give maximum freedom to private initiative and allow easy acquirement of mineral resources from the government. At the other extreme, in South Africa, Australia, and South America, an individual cannot secure title in fee simple; minerals must be developed on a lease or rental basis, with ownership remaining in the government.
Chapter 40
What does the author argue about nationalization of mineral resources?
The author argues that discovery and intelligent management of mineral resources, by their nature and infinite variety, require private initiative, and that government efforts in this field do not promise advantages outweighing the loss of that element. He frames the problem as determining what steps a government can take for public welfare while preserving and fostering private initiative.
Chapter 40
How does private ownership affect the pace of exploration?
The chapter states that where minerals pass into private ownership, exploration becomes a commercial arrangement between explorer and owner, and there is often some lag, especially with large blocks of land. Owners may be unwilling or unable to explore effectively, and terms may be less attractive than on government lands; it cites English coal leases averaging eight years to close.
Chapter 40

CHAPTER XVII. CONSERVATION OF MINERAL RESOURCES 3594 cards

What does Chapter XVII identify as the central problem of mineral conservation?
The chapter frames conservation of mineral resources as a problem involving both private and public efforts, and treats the interest rate as a guide in conservation decisions. It also examines how war produces anti-conservational effects, and uses coal as the main case study before turning to minerals other than coal.
Chapter 41
How does the chapter treat the interest rate in relation to conservation?
The chapter presents the interest rate as a guide in conservation, listing it as a distinct topic alongside the differences between private and public efforts. It does not reduce conservation to a single rule; instead it situates the interest rate within a broader discussion of how conservation decisions are made and who makes them.
Chapter 41
What does the chapter say about war's effect on conservation?
The chapter identifies anti-conservational effects of war as a specific topic in the conservation problem. It treats war as a force working against conservation rather than as neutral background, and places this discussion before the detailed treatment of coal conservation measures.
Chapter 41
What measures does the chapter list for conserving coal?
The chapter lists measures introduced or proposed to conserve coal: mining and preparation of coal, including progress in these methods; improvement of labor and living conditions at the mines; introduction or modification of laws regulating or removing restrictions on the coal industry; distribution and transportation of coal; utilization of coal; and substitutes for coal as a source of power.
Chapter 41

XVII. (part 1)3 cards

How did World War I change international coal trade patterns?
The war stopped Germany's great overseas coal exports and curtailed England's. The United States partly filled the gap, especially to South America, while Europe absorbed most British export coal and also needed American coal. After the war, England gradually resumed exports along old trade lines, but German overseas trade had not been reestablished and could not be for a long time if Germany fulfilled the Peace Treaty terms.
Chapter 42
What did the Peace Treaty require of Germany regarding coal?
The terms of the Peace Treaty lessened the territory of German coal reserves and required considerable additional contributions of coal to be delivered to France, Belgium, Luxemburg, and Italy. Because of slow recovery in German coal output, there was still considerable lag in the supply available for European countries. The chapter notes German overseas export trade has not been reestablished and cannot be for a long time if Germany fulfills the treaty terms.
Chapter 42
Why is coal classification difficult, and what is the fuel ratio?
The author explains classification is a perennial source of difficulty and controversy: coals grade completely from peat through lignite to bituminous and anthracite, many fall near border lines, and coal comprises several substances varying unequally. The earliest and most widely used classification is the fuel ratio—fixed carbon divided by volatile matter—based on proximate analyses. It roughly measures calorific power and discriminates higher-rank coals, but is unsatisfactory for lower ranks due to inert volatile matter and moisture.
Chapter 42

XVII. (part 2)3 cards

Why does following a coal seam require structural geology and stratigraphy?
The author explains that coal-bearing beds differ in thickness and competency, so folding may produce complex convolutions, and shearing between beds can give one seam an intricate outline while adjacent beds stay simple. Following a seam therefore requires structural geology at almost every stage, plus identification and location of sedimentary horizons, which requires stratigraphic principles.
Chapter 43
Which geologic period holds most of the world's high-grade coal?
The author states that high-grade coals of the eastern and central United States occur in Carboniferous rocks, the period whose very name comes from its productive coal beds worldwide. The coal measures of Great Britain, Germany, Belgium, northern France, Russia, and China's largest beds are all Carboniferous. This period includes the bulk of the world's anthracite and high-grade bituminous coal.
Chapter 43
What does the author say about future petroleum production and reserves?
The author argues reserves are rough approximations and further exploration will likely extend them, noting past predictions of exhaustion have failed as exploration increased. He expects shifts toward the Caribbean and Gulf of Mexico, and Persia and Mesopotamia, with Russia possibly becoming the leading producer. He sees the real problems as discovery keeping pace with demand and political control of oil resources.
Chapter 43

XVII. (part 3)4 cards

According to White, what coal fixed-carbon percentage signals poor oil prospects nearby?
White holds that where coal contains more than 65 to 70 per cent fixed carbon, chances of finding oil in the vicinity are not good, though commercial gas pools may still occur. He attributes this to geochemical distillation having gone far enough to volatilize the oils, leaving solid residues in the rock. The principle applies where oil and coal lie in the same geologic series, not where an unconformity separates them.
Chapter 44
How does White relate oil quality to the rank of associated coal?
White finds that the lowest rank oils, with considerable asphalt, occur where coal deposits are least altered, while lighter, higher rank oils occur where coal has reached correspondingly higher ranks. Up to the point of complete elimination of the oil, improvement in oil quality accompanies increased carbonization of the coal. The principle is useful in exploration only where oil and coal belong to the same geologic series.
Chapter 44
What is the inorganic theory of petroleum origin, and how does the author judge it?
The inorganic theory holds that oil comes from magmas and volcanic exhalations. Supporters cite hydrocarbons and carbides in igneous rocks and gases, geographic ties between oil fields and volcanic rocks, and oil domes in Mexico caused by igneous plugs. The author concedes some such theory may be needed to explain oil's ultimate source, but says evidence overwhelmingly shows organic agencies formed the principal known pools.
Chapter 44
What vertical arrangement of gas, oil, and water occurs under an impervious cap, and why?
When the impervious capping is punctured by a drill hole, gas is likely encountered first, then oil, then water, which is usually salty. The arrangement results from the lighter materials rising to the top. Gas pressure is often released with almost explosive violence, which has been suggested as an important cause of underground pressures; artesian flow has also been supposed to contribute.
Chapter 44

XVII. (part 4)4 cards

What two stages does Arnold divide oil exploration geologic work into?
The author quotes Arnold that exploration work divides into preliminary reconnaissances and detailed surveys. The reconnaissance gathers published and hearsay evidence of oil or gas seepages, makes preliminary surveys to determine source formations and their areal distribution, identifies regions with favorable surface evidence, and determines transportation routes and methods. The second stage covers detailed surveys of the most promising regions and locating test holes at favorable points.
Chapter 45
What does the author say about geologists applying principles from one district to another?
The author argues that each field has its own "habit," determined by the interaction of several geologic factors, which may be learned empirically. He states that geologists have often gone wrong in applying to a new district principles determined elsewhere, without sufficient consideration of the complexity and relative importance of the sundry geologic factors that in the aggregate determine the local habit of oil occurrence.
Chapter 45
How does the Beaumont field of Texas show anticlines are not always essential to trapping?
The author cites the Beaumont field of Texas as an instance where irregular primary deposition of sediments differing in porosity, both vertically and horizontally, allowed oil to migrate upward irregularly along porous beds and parts of beds, and to be trapped between the more impervious portions of the beds. This demonstrates that anticlines are not always essential to make the necessary trapping conditions.
Chapter 45
What are oil shales, and why are they not yet a major oil source?
Oil shales are sedimentary strata containing decomposed products of plants and animals, from which oil can be extracted by distillation; locally they grade into cannel coal. The author states the extraction problem is fairly well advanced technically and has become principally one of cost, requiring operations on approximately the scale of the coal industry. As long as sufficient naturally concentrated oil supplies exist, oil shale is unlikely to furnish a considerable percentage of world requirements.
Chapter 45

CHAPTER XVII (part 1)4 cards

How does Leith define conservation of mineral resources?
Leith defines conservation of mineral resources as an effort to strike a proper balance between the present and the future in the use of mineral raw materials. He notes that the conservational idea has wide sentimental appeal, but formulating and applying specific plans meets many difficulties, making it a live practical problem for mining men, engineers, geologists, economists, and public officials.
Chapter 46
Why did early estimates of mineral supplies prove too low?
Early estimates failed to account for mining to great depths and wide use of low-grade ores made possible by improved methods, and especially failed to emphasize probable new discoveries replacing exhausted supplies. Successive revisions have generally increased available supplies, pushing exhaustion far into the future for most important minerals and minimizing the urge for drastic immediate action.
Chapter 46
What two elements does Leith say the conservation problem involves?
Leith says conservation of raw materials is closely bound up with conservation of human energy. If saving a dollar's worth of raw material costs two dollars' worth of energy, the wisdom is questionable; it might be wiser to waste some raw material to save time and effort. He notes the United States is often called extravagant versus Europe, but output per man in mineral industries is far greater in the United States.
Chapter 46
How does the interest rate guide conservation, and how do governments differ?
Leith says economists emphasize the interest rate as a guiding, if not controlling, consideration: private capital is unlikely to invest in conservation unless capital and adequate interest return later. Governments are less bound—better credit, taxes not so direct, ability to balance losses against gains—and may fund conservation as national insurance without the interest return a private investor requires.
Chapter 46

CHAPTER XVII (part 2)4 cards

How does Chance defend coal left in pillars against claims of waste?
Chance argues coal left in pillars to support the roof is not waste but engineering efficiency of the highest type, because it uses the cheapest and least valuable material available for roof support and saves the whole labor cost of building supports from other materials. He notes an elementary calculation shows it is cheaper to use the coal than other material.
Chapter 47
What reasons does the chapter give for coal legitimately left in abandoned mines?
The chapter states a large portion of supposedly wasted coal is left in mine workings abandoned because the roof is unsafe and continuing would risk injuries or loss of life. Coal left to conserve human lives cannot be classed as avoidable waste. A small part is lost because it is intimately mixed with refuse and recovery costs would exceed its value.
Chapter 47
What difficulties hinder working upper coal beds before lower ones?
The chapter notes seams may be under separate ownership in some localities, creating a conflict of interests. Also, if the better seam lies below and poorer seams above, market conditions may require mining the lower seam regardless of destroying the upper ones. Mining a lower seam has often broken overlying strata, making upper seams unrecoverable.
Chapter 47
What evidence does the chapter give that coal recovery has improved?
Campbell and Parker state a much greater proportion of hoisted product now reaches market in merchantable condition, partly from better handling and saving of small sizes formerly sent to culm banks. Past mining loss averaged 50 percent; now 70 to 90 percent extraction may be expected. Anthracite recovery averages 65 percent versus 40 percent twenty years earlier.
Chapter 47

CHAPTER XVII (part 3)4 cards

Why can water power never largely replace mineral fuels, according to the chapter?
The author argues water power has limits: total commercially developable power is closely limited, and it is geographically mismatched with industry—over 70 percent of U.S. water-power resources lie west of the Mississippi while over 70 percent of installed horsepower is east. Electricity cannot be economically transmitted more than a few hundred miles, and hydro-electric power cannot substitute for coal in metallurgical and chemical processes or as ship fuel.
Chapter 48
What measures does the chapter suggest to extend water power use in the immediate future?
The chapter lists three: more complete utilization of existing water powers through more efficient machinery and methods; some redistribution of industries so power-intensive ones locate where water power is cheap and abundant; and interconnection of hydro-electric plants so full capacity is used. Some developed powers go underused because plants are not connected to distribution systems large enough to consume all the power.
Chapter 48
Which conservation measures does the chapter place beyond private interests and requiring government power?
The author argues private initiative has driven most advances—better mining, preparation, utilization, substitutes, larger control groups, labor conditions. Beyond private power lie elimination of resource or royalty costs, control of over-capitalization, removal of restrictions on concentration, permission for cooperation among competitors, regulation of selling-price minimums, and control of distribution. The interest rate is the limiting factor for private action.
Chapter 48
What is the most obviously helpful immediate step the government could take for coal conservation?
The author argues the government should permit cooperative arrangements under private ownership: common selling agencies to cut selling costs, division of territory to avoid excessive cross freights, and allotment of output in proportion to demand from various territories, eliminating excessive competition and over-production. These could work without public detriment if properly regulated, and the savings would allow conservational methods at mines without raising public cost.
Chapter 48

CHAPTER XVIII (part 1)4 cards

What share of annual world mineral production is used domestically versus shipped abroad?
About two-thirds of the annual world production of minerals is used within the countries where they are produced, and one-third is shipped to other countries. The chapter treats domestic consumption as a matter of national rather than international concern, and focuses on the portion that moves between countries.
Chapter 49
How concentrated is the world movement of individual minerals, according to the chapter?
The chapter states that the movement of most minerals shows remarkable concentration: manganese moves from three principal sources to four or five consuming centers, chromite and tungsten each from two principal sources, and coal is controlled by England, the United States, and Germany. Most individual minerals follow two or three salient lines of movement, reflecting limited sources with favorable location, grade, transport, and cost.
Chapter 49
What war changes does the chapter cite in mineral supply and trade?
The chapter says the war changed demand, cut off customary sources, and disrupted finance and shipping. Examples: manganese from India and Russia stopped, so Brazil was developed; Spanish pyrite was replaced by domestic supplies; German potash was cut off; Chilean nitrates were diverted to powder; US mineral imports fell by 1,200,000 tons. Inter-Allied committees allocated nitrate, tin, tungsten, and platinum.
Chapter 49
What post-war tendencies toward government involvement and international cooperation does the author describe?
The author argues the mineral industry has not reverted to pre-war conditions: shipping is disturbed, German control abroad is weakened, and the Reparations Committee holds great power over German minerals. An international coal commission distributes coal in Europe. The author notes governments outside England and the US have extended eminent domain, and that all governments except the US now take active roles in mineral trade, closing parts of the world to private initiative.
Chapter 49

CHAPTER XVIII (part 2)4 cards

What does the author argue about total world mineral supplies as a reason for international cooperation?
The author argues this argument has been much exaggerated. Except for certain wartime periods, adequate supplies of all mineral commodities have generally been available worldwide, developed as rapidly as needed—sometimes more rapidly. Geological conditions suggest this will continue through national and individual effort. The main problem, he contends, is not total supply but effective and equitable distribution, with more danger of over-development than shortage.
Chapter 50
Why does the author call artificial barriers to mineral distribution anti-conservational?
Mineral supplies are concentrated in few localities and no nation has all varieties, so tariffs or restrictions impose unnecessary handicaps. If ferro-alloy-rich countries restricted distribution, the steel industry and civilization would bear large costs. If the U.S. imposed high tariffs to become fully self-supporting, low-grade domestic deposits would exhaust earlier and domestic steel costs would rise—cost representing human energy times raw material.
Chapter 50
Which minerals must the United States depend on almost entirely from other countries?
The chapter lists four: cobalt, nickel, platinum and metals of the platinum group, and tin. These fall in the class where the U.S. must depend almost entirely on foreign sources. This is distinct from a larger class—including antimony, chromite, manganese, potash, tungsten, and petroleum—for which the U.S. will depend on foreign sources for a considerable fraction of supply.
Chapter 50
What does the author say about the United States' stake in international mineral control?
The U.S. is more nearly self-sustaining in minerals than any other country, with a potential export surplus about twice that of all the rest of the world combined. The author argues this gives the U.S. the heaviest stake in any international control scheme and perhaps the most to lose by restriction, justifying a broad, liberal view of importing needed minerals rather than extreme wartime self-sufficiency.
Chapter 50

CHAPTER XVIII (part 3)4 cards

Which sources does the chapter recommend for fuller discussion of international mineral resources?
The chapter refers readers to U.S. Geological Survey reports, especially the World Atlas of Commercial Geology (1921), and U.S. Bureau of Mines reports. It also lists Political and Commercial Geology, edited by J. E. Spurr (1920); Strategy of Minerals, edited by George Otis Smith (1919); Coal, Iron and War by E. C. Eckel (1920); and works by Brooks and LaCroix on the Lorraine iron field.
Chapter 51
What does the chapter's footnote say about the word 'control'?
Footnote 59 states that 'control' is used in a very general sense, covering activities ranging from regulation to management and ownership. The context will usually indicate that the word means regulation when governmental relationships are being discussed.
Chapter 51
Which two authors wrote on the Lorraine iron field and the war?
Alfred H. Brooks and Morris F. LaCroix co-authored The Iron and Associated Industries of Lorraine, the Sarre District, Luxemburg, and Belgium, published as Bulletin 703 of the U.S. Geological Survey in 1920. Brooks also wrote The Lorraine Iron Field and the War in Engineering and Mining Journal, volume 109, 1920, pages 1065-1069.
Chapter 51
What does footnote 58 cite Umpleby's work as?
Footnote 58 cites Joseph B. Umpleby's Strategy of Minerals--The Position of the United States Among the Nations, published by D. Appleton and Co., New York, 1919, page 286. This is the chapter's citation for Umpleby's contribution to the discussion of mineral strategy.
Chapter 51

CHAPTER XIX4 cards

What did wartime mineral self-sufficiency studies reveal about market requirements?
The author states that the war-time breakdown in international commercial exchange led nations to appraise mineral reserves more intensively for self-sufficiency. This required studying mineral uses, international mineral movements, and the link between domestic and foreign production. The domestic mineral industries learned that market requirements are based on ascertainable factors and do not just happen.
Chapter 52
What permanent advance in mineral products came from wartime standardization efforts?
The author argues that increased attention to better sampling and standardization of mineral products was a permanent advance, aiding competition with standardized foreign products. The Southern Graphite Association, for example, guaranteed more uniform supplies and thereby a broader, more stable market. Such movements allow use of heterogeneous mineral supplies in a distinctly conservational manner, regarding both mineral reserves and human energy.
Chapter 52
What did German geologic maps of the front represent for officers?
The author reports that perhaps 150 German geologists prepared and interpreted front maps for officers. Features included topography; rock kinds and distribution; usefulness as road and cement materials; adaptability for trench digging and trench shapes; weathering of thrown-out material; ground-water conditions and water-table depth by season and rock; drinking water supplies; rock behavior under explosives and shell-penetration resistance; underground conditions for tunnelling and mines; and electrical conductivity of rocks.
Chapter 52
How did the American Expeditionary Force's geologic service develop and what did it cover?
The author notes the AEF was slow to use geology, but a service began in September 1917 under Lieutenant-Colonel Alfred H. Brooks. For ten months it had only two officers and one clerk; in the last two months before the armistice there averaged four geologic officers on the General Staff, plus geologists with engineering units. Work covered field works, water supply, and road material, with water reports covering nearly 15,000 square kilometers.
Chapter 52

CHAPTER XX3 cards

What geologic factors must be studied before building a large modern dam?
Before dam construction, analysis must cover the rocks' supporting strength relative to the dam's weight, whether water will leak around or beneath the dam, and whether zones of weakness could allow shearing of foundations under the combined weight and ponded-water pressure. It must also be determined whether the valley is rock or partly filled with debris, the debris depth, and its behavior under load when saturated.
Chapter 53
Why do modern heavy structures require more careful foundation study than lighter ones?
The author argues that foundations of modern structures such as heavy buildings, especially in untried localities, demand much more careful consideration of the substrata than lighter structures required. Planners must know the kinds of rocks to be excavated, their supporting strength, their structures, difficulties likely from water, and other geologic features. Failure to attend to these factors has led to some disastrous results.
Chapter 53
Which physiographic factors matter in planning bridge foundations and abutments?
Bridge foundation and abutment planning requires geologic knowledge similar to that for heavy buildings. In addition, certain physiographic factors must be considered, specifically those affecting the nature and variation of stream flow and the migration of shore lines.
Chapter 53

CHAPTER XXI. THE TRAINING, OPPORTUNITIES AND4 cards

What distinction does the chapter draw between pure and applied science?
The chapter treats pure and applied science as distinct pursuits, with the economic geologist working in the applied realm. It frames the training and opportunities of the economic geologist around this division, presenting applied work as its own professional field rather than a lesser branch of pure research.
Chapter 54
What course of study does the chapter suggest for aspiring economic geologists?
The chapter outlines a suggested course of study that includes field work and specialization in studies, culminating in a degree of Economic Geology. Field work is given its own heading, indicating the author considers practical outdoor training essential alongside specialized academic coursework rather than an optional supplement.
Chapter 54
What opportunities does the chapter attribute to the economic geologist?
The chapter devotes a section to the opportunities of the economic geologist, presenting the profession as offering meaningful career prospects. It treats these opportunities as a distinct topic worth separate treatment, following the discussion of training and preceding the treatment of professional ethics.
Chapter 54
What does the chapter say about the ethics of the economic geologist?
The chapter closes with a section on the ethics of the economic geologist, treating professional conduct as a subject requiring explicit discussion. It places ethics after training and opportunities, suggesting the author views ethical standards as integral to the profession rather than incidental to technical competence.
Chapter 54

CHAPTER XXI (part 1)4 cards

What does the author say about standardizing a course of study for economic geology?
The author states that economic geology is an established profession but there is nothing approaching a standardized course of study leading to a degree in it. Training varies as widely as the institutions teaching geology, and even within one institution no two persons take exactly the same groups of studies. This allows wide latitude to meet changing requirements but is undesirable in other respects.
Chapter 55
What does the author argue about the pure versus applied science debate in geology?
The author argues that yielding wholly to pressure for applied courses would crowd out essential basic studies, yet refusing applied geology because pure science alone is scientific is equally objectionable. He says economic applications do not necessarily mean non-scientific work; the lag of science, not absence of possibility, explains unorganized fields. He calls the academic tendency to view applied work as less worthy extremely unfortunate.
Chapter 55
What course of study does the author recommend for a student preparing for economic geology?
The author recommends emphasizing fundamental branches first: general geology, stratigraphy, paleontology, physiography, sedimentation, mineralogy, petrology, structural and metamorphic geology, physics, chemistry, mathematics, and biology. Only after these should economic applications get as much time as permits. He advises that experience supplies deficiencies in applied knowledge but will not make up for lack of basic principles, and that there is no royal road to success.
Chapter 55
Why does the author value field work and quantitative training for geologists?
The author says field work is essential, should be taken at every opportunity, and no summer should pass without geologic practice; he favors roughly equal division between indoor and outdoor study as a corrective to clear thinking. He also emphasizes the quantitative approach—training in mathematics and laboratory practice—because geology is passing from descriptive and qualitative stages to a more precise basis.
Chapter 55

CHAPTER XXI (part 2)4 cards

What does the author say about financial rewards in geology careers?
The author argues that large financial rewards are perhaps more likely to be gained through perfected training and experience in state and national surveys and educational institutions than through early concentration in the commercial field. He adds that the financial side will take care of itself once sufficient knowledge and proficiency are attained in any branch of the science.
Chapter 56
How does geology serve as training for administrative and public careers?
The chapter states that geology has proved its value as training for administrative and other public careers, and the profession contributes its full share of men to these activities. Because the practice of geology deals with a wide variety of factors and requires constant judgment in balancing, correlating, and integrating them, this objective treatment of complex situations is valuable training for handling human affairs.
Chapter 56
What position does the author take on geologists avoiding commercial work?
The author argues against the view that the geologist should hold himself aloof from business or applied phases of his profession. He says this argument would apply equally to the engineer, and carrying it to its logical conclusion would mean withdrawing scientific aid from industry. Instead, the economic geologist should help raise ethical standards in his part of the field.
Chapter 56
How should an economic geologist handle ethical questions in practice?
The author argues that no special ethical code can be comprehensive, detailed, and elastic enough to cover all contingencies, nor would it improve on the spirit of the Golden Rule. The geologist should carefully appraise all conditions of a problem, understand fully how his report will be used, and refuse to act where questionable ethical standards are apparent or suspected.
Chapter 56

CHAPTER XXI (part 3)4 cards

What does the chapter say about the relation of ground-water to military operations?
The chapter lists ground-water among geologic factors bearing on military operations, citing pages 78-79 and 408, 410-411. It also notes ground-water's relation to rock slides at pages 78 and 416-417. Ground-water is treated as a practical concern for engineering and military planning, not merely a theoretical topic.
Chapter 57
What does the chapter say about the origin of ore deposits by hot waters?
The chapter cites evidence of ore formation by hot waters at pages 37-41, and links hot springs to ore deposits at pages 40 and 258-259. It also treats magmatic waters as evidence for ore formation by hot waters. These references support the view that hot waters play a role in depositing ores.
Chapter 57
What does the chapter note about the Long-wall system of coal mining?
The chapter describes the Long-wall system's conservational aspect at page 368, and notes that it causes subsidence of overlying ground, leading to litigation, at pages 357 and 417. So the method is presented both as a conservation question and as a source of legal disputes over surface damage.
Chapter 57
What does the chapter say about the anti-conservational effect of war on iron ores?
The chapter states that war has an anti-conservational effect on iron ores, citing page 365. This appears in the context of conservation of mineral resources. The point is that wartime demand works against conservation of iron ore reserves, not that war depletes them in some other way.
Chapter 57

CHAPTER XXI (part 4)4 cards

What does the chapter's index indicate about the Sudbury, Ontario district's mineral ores?
The index lists Sudbury, Ontario, as a source of cobalt (page 255), nickel ores (pages 34-35, 180-182, 308, 312, 318), and platinum (pages 238, 239). This shows the district is associated with multiple mineral resources rather than a single ore, and the entries point readers to the specific pages where each is discussed.
Chapter 58
According to the index, what anti-conservational effects are attributed to tariffs and duties?
The index entry on tariffs and duties states their anti-conservational effect, citing pages 362-363, 366, 375, 376, and 393-394. It also lists proposed tariffs on mineral resources at pages 175-176, 179, 184, 192, 248, and 257-258. The chapter thus links tariff policy to conservation outcomes, treating duties as potentially working against conservation rather than for it.
Chapter 58
What wartime applications of geology does the index list, and which agencies are named?
The index lists war's anti-conservational effects (pages 365-366), application of geology to war (pages 405-412), and war's effect on ad valorem valuations (page 335). Named agencies include the War Industries Board, War Minerals Committee, and War Trade Board (pages 356, 406), plus the U.S. Bureau of Mines and Geological Survey's wartime activities (pages 406-407).
Chapter 58
What does the index say about the relation of structural geology to economic geology and exploration?
The index lists structural geology's relation to economic geology at page 5, and the use of structural principles in exploration for mineral deposits at pages 319-320. It also notes rock structures' relation to earth stresses (page 5) and to topography (page 7). Structural geology thus appears as both a foundational and a practical exploration tool.
Chapter 58

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All questions and answers

What did the author say is required for professional preparation in economic geology?

What is the erosion cycle, and what stages does it pass through?

How does physiography aid in reading underground structure?

Why are stratigraphy and paleontology vital to economic geology?

What does the chapter say economic geology includes, in terms of man and environment?

How does the chapter illustrate that new materials enter economic geology over time?

What does the author say about the statistics and figures used in this volume?

Why does the author draw illustrative cases mainly from the Lake Superior region?

What are the two main chemical types of igneous rock and their estimated proportions?

How do sedimentary rock mineral proportions differ from igneous, and why?

In what proportions must shale, sandstone, and limestone form to match parent igneous rock?

Why do commercially important minerals barely appear in abundance tables?

How does Leith classify mineral deposits formed directly from cooling magmas?

What evidence does Leith cite for an igneous source of ore deposits?

What is the zonal arrangement of minerals related to igneous rocks?

How does Leith define anamorphism of mineral deposits?

Why does the economic geologist emphasize the origin of mineral deposits?

Why are the terms primary and secondary problematic in economic geology?

How does Ransome define hypogene, supergene, and protore?

What features suggest the Sudbury nickel ores segregated within the norite magma?

What evidence suggests ore solutions were hot and from deep magmatic sources?

How does the author explain the possible role of meteoric waters in these deposits?

What is the zonal arrangement of ores around igneous rocks, and what exceptions exist?

How are deposits classified by depth of formation, and what characterizes each zone?

What is the zone of secondary sulphide enrichment and how does it form?

Why does the author question the importance of secondary sulphide enrichment?

What are residual mineral deposits formed by weathering of igneous rocks in place?

Why does the author say published descriptions of enrichment processes are often misleading?

How does anamorphism affect iron ore versus coal, per the chapter?

What three principal ways does the chapter say produce the main mineral values?

What does the chapter say about why only some igneous rocks carry valuable minerals?

What share of world annual mineral production does coal represent by tonnage and by value?

Why is mineral production concentrated around the North Atlantic basin, according to the author?

How does water compare with other mineral resources in tonnage and value?

What does the author conclude about world mineral reserves, and which commodities are exceptions?

Why is water considered a mineral resource from a geological viewpoint?

What is the zone of saturation and its upper boundary called?

What essential conditions produce an artesian well?

Why does the author say geology matters in tunnel planning and bidding?

What did Chamberlin and Salisbury calculate about the strength of rock masses?

What causes slides, and what factors may disturb equilibrium?

What did the Panama Canal experience reveal about drainage and soft rock?

What are the principal commercial factors determining availability of common rocks?

What does the commercial term 'granite' include, and what are its main uses?

How does chalk differ from limestone in source and use in the US?

What are the principal uses of clay, and how did war affect imported clays?

What three nutrients may soils lack, and what does cropping remove?

What is the origin commonly believed for the Chilean nitrate beds?

How is phosphate rock made available to plants, and what does that require?

How did war expose the world's dependence on Chilean nitrates?

What are the main uses of coal worldwide, and in what proportions?

Which countries lead world coal production, and in what shares?

How are the world's coal reserves distributed by continent?

What does the author argue about coal reserves and future industrial development?

What did Hoover's statistical study of metal mines find about depth and profit?

How was the Swedish iron coefficient calculated and applied to estimate continental resources?

Why does the author argue that understanding ore origin is the geologist's most effective exploration tool?

What percentage factors did Leith give for ore in the Mesabi and rest of Lake Superior iron formations?

What technical and commercial factors determine which iron ore materials are used?

How does the chapter classify iron ores by geologic origin?

What does the chapter say about world reserves and future iron ore production?

What determines whether an iron ore is commercially usable beyond its iron percentage?

How do steelmaking processes differ in the phosphorus content they allow?

Why does iron ore tend to move to coal regions rather than the reverse?

How self-sufficient is the United States in iron ore and ferro-alloy minerals?

According to the chapter, what determines the availability of iron ore?

How were the Lake Superior iron ores formed, according to the chapter?

What share of world iron ore production comes from sedimentary rocks?

Why does the chapter say silica's solubility is often questioned?

What are Cuban iron ores, in terms of their origin and relation to laterites?

What share of manganese consumption goes to steel, and how much manganese does a ton of US steel require?

How do low-grade and high-grade manganese ores differ in grade and in the alloys they make?

What happened to the US manganese industry when war shipping was released and foreign ore returned?

How does the garnierite (lateritic) type of nickel ore form, as at New Caledonia?

What are tungsten's main uses and typical ore grades before and after concentration?

What geologic types host tungsten ores, and how important is secondary concentration?

Where does vanadium come from and what are the origins of the Colorado-Utah deposits?

What two types of magnesite deposits does the chapter describe, and how do they differ?

What purity standards must fluorspar meet for steel-making versus chemical and enameling uses?