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By R. J. Colony

MINING geology does not lend itself - very readily to a review embracing "improvements in methods," as perhaps do shop practices or laboratory procedures. The "methods" used in mining geology are simply the application of geology to mining; winning the ore, the handling of material, mechanical appliances, all belong strictly to mining proper, and have no place in a review of geology as applied to mining. A comprehensive review would necessarily cover a .very broad field, which could be subdivided into many -parts. Only a few of these can be discussed here. .Those that have been suggested to the chairman indude :

Jan 1, 1930

By H. D. B. Wilson, W C. Brisbin

The Thompson-Moak Lake nickel belt lies along the root of a Precambrian mountain range of the island-arc or alpine type. This range coin-. cides with the boundary between the Superior and Churchill blocks of the Canadian Precambrian shield. The nickeliferous peridotites and nickel ores occur along a negative gravity strip, which also coincides with strong thrust faulting and the axis of greatest deformation of the mountain range. Similar structures and highly nickeliferous peridotites occur in present-day island arcs. Much of the belt is covered by Paleozoic rocks, but a length of 270 miles may be explored by present-day methods. Nickel deposits have been located along 60 miles of the belt. The length of the favorable structure and the size of the known deposits suggest that this will be one of the world's major nickel regions. The regional gravity anomalies, which consist of a branching negative strip bordered by two positive strips, are best explained by major warps of a crust consisting of a granitic and basaltic layer. The ore deposit

Jan 1, 1961

By George F. Kunz

Jan 1, 1902

By D. A. Singer, J. C. Griffiths

"One of the most useful approaches to a complex problem is to model the system which gives rise to the problem and to perform simulations through the model to find appropriate solutions. The Engel Model may be used as such a simulator to investigate the problem of the exploration for natural resources.The Engel Model is based on a two-stage search procedure in which a known area (A) which contains m prizes is subjected to search by n coverings. During the first-stage search the sensor system records signals which may be a response from prizes (that is, true signals) or may be false. Signals tend to cluster around a prize and a cluster size consists of s signals. If a circle of radius R is drawn around each signal some will overlap and the overlap from s signals contains a prize. The cost of a single covering in which each point of the area comes under observation once, is designated E1. Second-stage detailed search is expensive and is confined to areas of overlap of s circles; it leads to the location of prizes. Second-stage search of the whole area costs Ea units. The expected value, V, of a prize is known and its development cost is E3 units.The sensor system characteristics are defined by the circle of radius R around a signal, which should be small compared with the total area A and enters the model as a parameter a x R2/A. The probability of a false signal during a single covering of a circle of radius I is a known constant, A.This model was applied to the search for uranium ore bodies using two different types of occurrence. In the first, the Wyoming Basin type, the area is relatively large (A = 1 496 square miles) and a few (m = 4) large prizes occur (expected value V = $30 million). In the second area, which represents the Ambrosia Lake region of New Mexico, the area is smaller (A = 212 square miles) and contains many (m = 200) smaller prizes (expectedvalue of a prize V,$2 million). The three costs, E1, E2, E3, are adjusted to the different circumstances in the two areas.Simulations were performed using n = 1 to 40 coverings with cluster sizes s = 0 to 19; the radius R was varied from 0.52 to 3 miles (and, therefore, a = 0.002 to 0.133 0, respectively, dependent on the area of interest). The value of A was varied from 0.01 to 0.10.Profitable programs were found over a wide range of the parameters; the two areas required different strategies to achieve maximum profit. In the Ambrosia Lake region a few passes (n = 4 to 6) with small cluster sizes (s = 2 to 6) are more profitable, whereas in the Wyoming Basin region a large number of passes (n = 35 to 40) and cluster sizes of s = 5 to 10 are most profitable.As pointed out by Allais (1957) the larger prizes are the most important in deciding the successful outcomes of exploration programs, and the profit margin in the search for a few large prizes is sufficient to yield success over a wide range of programs. Such programs require very large investments if they are to be successful.To refine the Engel Simulator as a decision-maker in selecting the most profitable exploration programs it is necessary to obtain firm estimates of the sensor system characteristics, that is, of R, a and ? (lambda)."

Jan 1, 2014

By LUIS ALBERTO TORRES-CRUZ

The assessment of liquefaction vulnerability is crucial to understanding the potential consequences of a tailings dam failure. The “Plewes method” is a relatively well-known and simple screening method to assess liquefaction potential based on results of cone penetration testing (CPT) which may be complemented with laboratory testing. The objective of the current work is to emphasise the screening nature of the method and its uncertainties when applied in tailings deposits. Specifically, the paper highlights the difficulties in assessing the intrinsic uncertainty of the method and the additional uncertainty that results from variations of the slope of the critical state line (λ10) along the depth of the CPT sounding. The results of the method are too uncertain for detailed characterisation of tailings even when a relatively low intrinsic uncertainty is assumed. However, the method characterises weaker soils with lower uncertainty (although still too high for detailed characterisation) than stronger soils. The uncertainty of the method is negatively affected by the relatively low λ10 values that are typical of nonplastic tailings. It is suggested that the results of the method should be presented in scatter plots in which the spread of the data is consistent with the uncertainty of the method.

Jan 28, 2021

The first metal-mine accident-prevention course was prepared and published in 1942--45 as a series of seven miners' circulars (Nos. 51-57). The scope of the course has been broadened, revised, and brought up to date, and it is being published as a similar series of seven miners' Circulars (Nos. 51-57, revised) on accident prevention in metal and nonmetallic mines. These circulars are: Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1957

By FREDERICW K. BRADLE

I HAVE been puzzled by two lines of thought'; one emanating from Washington, D. C., to the effect that we must all cheer up, that in a very short time, measured in terms of months, prices would begin to recover, business would become normal, and prosperity would continue on its way just as before the interruption of a year ago; and a second, coming from certain industrialists and economists, expressing fears that all commodity prices were in for a long downward trend, which would cause much unemployment, eventually drag down wages and so restrict purchasing power as to further aggravate the situation. One basis for the fear of a downward trend in commodity prices' is that ifter great wars a depression could last for something like 40 years-the downward trend to such a depression after our recent World War having been postponed for some reason or other; and the basis for another fear was that the production of gold was becoming less. I had 'also been trying for some time past to refresh my recollection as to how my ow11 particular lead interest climbed out of the depression of 1893; and as all the metals have had, and still have. relative values and prices, I can best express what I have in mind by talking principally about lead.

Jan 1, 1930

Geophysical Abstracts 1 - 86 wore issued in mimeographed form by the Bureau of Mines; Abstracts 87 - 111 were published in bulletins of the Geological Survey; Abstracts 112 - 119 were issued in mimeographed form by the Bureau of Mines as Information it ion Circulars 7256, 7257, 7267, 7273, 7285, 7292, 7303, and 7310. 1. GRAVITATIONAL METHODS 7786. Barton, D. C.3/ Case Histories and Quantitative Calculations in Gravimotric Prospecting. Am. Inst. Min. and Meat. Eng., New York, Tech. Pub. 1760, 1944, 49 pp.

Jan 1, 1945

By J. R. Campbell

THE need for standardizing methods of arriving at definite conclusions regarding the cleanability of a given coal, and for measuring the performance of coal-cleaning equipment, is constantly increasing. Earlier notes by the author on this subject are amplified in this paper, because he believes that better preparation of bituminous coal is a partial solution of the coal operators' troubles. WASHABILITY STUDIES The term "washability" of coal was coined when washing was the universal method of separating coal from its impurities by utilizing their difference in specific gravity. This and analogous terms are still used in their broad sense although pneumatic or air separation is now used to clean coal. These terms are so used in this paper. Too much time or money, can hardly be spent on "feed surveys" to get a "picture" of the coal that is to be cleaned. There have been too many "rule of thumb" methods used. Screen analyses and "sink-and-float" tests on the raw coal enable the coal operator and washery man to predict within reasonable limits the results that may be expected from any efficient cleaning apparatus.

Jan 1, 1928

By J. N. Van der Merwe, D. P. Roberts

The two components of pillar design formula being used in South Africa are pillar strength and pillar load. While considerable effort has been directed to the determination of pillar strength, the other half of the safety factor equation, the load, has not received the same amount of attention. The load acting on pillars has always been calculated using the Tributary Area Theory (TAT). This paper summarises the recent studies on coal pillar loading using various numerical models. It concludes that although there are meaningful differences under certain circumstances, there is still a compelling argument to use the TAT in coal pillar design. Les deux parties composantes de la formule de conception de pilier généralement utilisée en Afrique du Sud sont la résistance de pilier et la charge de pilier. Tandis que des efforts considérables on été dirigés vers la détermination de la résistance de pilier, l’autre moitié du facteur de sécurité n’a pas reçu la même attention. La charge agissant sur les piliers a toujours été calculée avec la Théorie d’Aire Tributaire (TAT). L’étude présente résume les études récentes sur la charge de pilier de charbon utilisant des modèles numériques variés. La conclusion est que bien qu’il y ait des différences significatives selon les circonstances, il y a toujours un argument puissant pour utiliser le TAT dans la conception de pilier de charbon. Die in Südafrika für die Auslegung von Pfeilern verwendeten zwei Formelkomponenten sind Pfeilerstärke und Pfeilerbelastung. Während beträchtlicher Aufwand zur Bestimmung der Pfeilerstärke gemacht wurde, wurde der anderen Hälfte der Sicherheitsfaktorsgleichung nicht die gleiche Aufmerksamkeit gewidmet. Die auf die Pfeiler wirkende Last wurde immer unter Verwendung der Tributary Area Theory (TAT) berechnet. Diese Arbeit fast neuere Studien betreffend der Belastung von Kohlepfeilern unter Verwendung verschiedener numerischer Modelle zusammen. Die Schlussfolderung ist, daß obwohl unter bestimmten Vorraussetzungen bedeutende Unterschiede existieren, nach wie vor ein bezwingendes Argument besteht TAT in der Kohlepfeilerauslegung zu verwenden.

Jan 1, 2003

By TSUYEE PEI

I FEEL greatly honored and appreciate this opportunity to be able to say a few words about that rather perplexing subject, silver. The constant decline in the price of this metal has now reached the stage where it is of much concern and the cause of serious discussion among the leading financiers, economists, and statesmen of the world. Further- more, it is significant that this subject is so important that almost every day one can read articles pertaining to it in the newspapers and trade publications. Being essentially a banker, and not an economist, I do not claim to be an authority on the silver question. These remarks are merely some of my observations in, regard to the many puzzles which-I came across in my recent studies of this very important question.

Jan 1, 1931

By AIME AIME

THE American Engineering Council, which is the working body of The Federated American Engineering Societies, held its first meeting in Washington, Nov. 18 and 19, 1920. The Federated American Engineering Societies was formed in Washington in June and is composed of engineering and technical societies, national, state, local and regional. These Member Societies elect delegates to the American Engineering Council, which is the administrative body of the Federated. The meeting was called to order by Richard L. Humphrey, Chairman of the Joint Conference Com¬mittee, and the program (which is printed below) was carried out without substantial change by E. S. Carman, who was elected temporary chairman. Under the Constitution, the Council appoints an Executive Board, the members of which are chosen according to the proportional membership of the vari¬ous Member Societies in their respective districts. Under this plan, with the present membership, 'the national societies will have 14 members and the local societies 6 members on the Executive Board.

Jan 1, 1920

Dry weather since the third week in January has set back any prospects for an early increase in hydroelectric power in the Pacific Northwest, according to The Bonneville Power Administration. The 25% cutback made in July probably will not be restored in March or April. Noranda Aluminum, Inc., increased its price for 99.5% aluminum ingot from 66 cents to 70 cents per pound effective March 1, 1980. Revere Copper & Brass, Inc., also -increased its price for primary aluminum from 66.0 cents to 70.0 cents per pound effective February 1. Kaiser Aluminum & Chemical Corp. raised its international price for 99.5% primary aluminum from 72.6 cents to 82.6 cents per pound, c. i. f., effective February 26 on new orders and on shipments from March 15.

Jan 1, 1980

By E. H. Boyle

The Bureau of Mines has evaluated the potential availability of silver from 436 mines and deposits in 41 market economy countries (MEC?s) comprising five major economic categories of deposits: predominantly silver deposits and predominantly zinc, lead, copper, and gold deposits. This study evaluated the long-term cost and availability of primary silver production from 53 producing and 13 nonproducing predominantly silver properties in 11 MEC's and estimated the total recoverable silver from 370 properties as a coproduct or byproduct of zinc, lead, copper, or gold production. This study resulted in estimates of a demonstrated resource of 5.99 billion tr oz of recoverable silver as of January 1984. Of this total, 23.5 pet is in the 66 mines and deposits classified as predominantly silver properties. The largest quantity of recoverable silver, 43.9 pct, lies in the 121 properties classified as predominantly zinc, with 26.5 pct in 120 properties classified as predominantly copper, 4.1 pet in 21 predominantly lead properties, and 2.0 pct in 108 predominantly gold properties. At current silver prices, the economics of silver production favor silver that is a byproduct or coproduct of zinc, lead, copper, or gold, and much of the silver production in the United States from the predominantly silver mines is at an economic disadvantage in comparison with silver production in other countries.

Jan 1, 1986

By H. C. Meister

THE zinc-smelting industry of the United States has grown very rapidly in recent years and bids fair to outrival that of all other countries in the future. On account of the geographical situation of the chief ore-supplies, the industry may be divided into two main groups, the eastern and the western. The eastern and older group includes the works of Pennsylvania, New Jersey and Virginia, which practically control their own ore-supply. The western group includes the works of Illinois, Missouri, Kansas, Wisconsin and Indiana, which do not control their own ore-supply, but are compelled to buy the ore in the open market. It is for this reason that the western zinc-smelting industry has been undergoing continual changes since its inception 40 years ago. During the early discoveries of lead- and zinc-ore in the lead- and zinc-districts of Wisconsin and northern Illinois, the zinc-ore (sinithsonite or " bone " as the miner calls it) had no value and was considered waste; but later, when this ore was found in large quantities, it attracted the attention of metallurgists, which finally resulted, during the early sixties, in the building of the Matthiessen & Hegeler Zinc Works at LaSalle, Ill., the pioneer zinc-works of the West. A few years later, zinc-ore was discovered associated with the lead-ore in Jefferson county, southeastern Missouri, which started the industry at Carondelet or South St. Louis. Still later, the discoveries of zinc-ore in the lead-ore region, first' at Granby and then around Joplin, lead to the introduction of the industry in the southwest Missouri and Kansas districts. At first the development of the industry was slow, but it progressed steadily and it is now one of the leading metallurgical industries of the middle West.

Jan 1, 1905

By E. D. Gardner

This paper discusses small-scale lade gold mining and milling. It is abstracted from a bulletin being prepared by the United States Bureau of Mines entitled "Equipping, Developing, and Operating Small Gold Mines." Gold is widely distributed in the mountainous regions of the United States; relatively few deposits, however, can be profitably worked on a large scale. Because of the high intrinsic value of gold, ores containing this metal may be very rich; hence it is possible to mine profitably smaller bodies of gold ore than of the more common metals.

Jan 1, 1934

By Corwin L. Cooper

This vapor, which describes mining and milling methods and costs at the Knob Hill gold mine, is one of a series being prepared by the Bureau of Mines on gold mining and milling practices in the United States. The mining properties owned or controlled by Knob Hill Mines, Inc., are situated in the Eureka mining district on a country road 2 miles up Eureka Gulch from the town of Republic, county seat of Ferry County, Wash. The district is about 140 miles northwest of Spokane by road and 35 miles south of the international boundary line. The altitude at the mine office is 2,700 feet.

Jan 1, 1940

By Michael L. Wayman

Archaeological and ethnographic work during the last century has shown clearly that metals have played a small but important role in prehistoric Arctic cultures. For at least the past several millenia both iron and copper have been used in the North, primarily for blades, projectile points, knives, awls, engraving tools, fishhooks, scrapers and axes. In addition they were used for joining purposes as staples and rivets. It is of great interest to enquire into the origins of these metals. In this connection one begins with the observation that to date there has been no clear evidence for the smelting or melting of metals in the Arctic prior to the arrival of Europeans. This can be explained partly by the absence of traditional pyrotechnologies such as the high-temperature firing of ceramics and the heat treatment of bone and wood. Another factor which surely inhibited the development of smelting/ melting operations is the relative absence of wood in the region. The production of charcoal for smelting requires large quantities of wood, to the extent that the desertification of a number of areas in the Old World is believed by some to have been at least partly caused by charcoal production. In the North this was obviously not possible. Thus the Arctic peoples were restricted to using native (naturally occurring) metals and metals obtained by various direct and indirect forms of contact with areas of the world where smelting was practiced. Both of these sources were important in the case of iron; we know that meteoritic iron, telluric (native) iron and smelted wrought iron were all used in the Arctic. These three types of iron will be considered in tum.

Jan 1, 1999

By Yun-Jie Wei

Seismic areas were in the eastern margin of the Qinghai-Tibet plain, whose structures were complicated, mainly composed of Maowen fault, Yingxiu fault and Pengxian-guanxian fault. The rapid rise of the Qinghai-Tibet plain led the crustal material of the eastern edge to move to the southeast along the faults on a large scale since the late Cenozoic; Minshan block structure and Long Men Mountain tectonic zone represented the strong nappe thrust movement as the east boundary of Chuanqing slip block; the stress was accumulating when squeezed, which to a certain extent resulted in breakdown of the crust, and earthquakes. The shock speed, high-energy accumulation, and the reversed dextrorotation of the earthquake fault characteristics et al. happened, which caused the development of secondary geological disastersts. According to on-site investigation, the typical geological disasters had thrust rock collapse, the instability deposit, the revival of potential debris flow et al. whose genetic model had been analysed.

May 1, 2009

By James R. Wait

An attempt is made here to collect together various reports and publications that are based on research supported all or in part by Contract No. H0155008 for the past two years. The subject matter deals primarily with the excitation, transmission, and reception of electromagnetic waves in mine environments. This contract from the U.S. Bureau of Mines with the Office of Telecommunications supports the efforts of James R. Wait (Principal Investigator and Consultant to OT), David A. Hill (Co-Investigator), and various associates within the Boulder scientific community. The contributions of Samir F. Mahmoud were supported, in part, by the contract while he was a Visiting Fellow with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado. Administrative assistance in CIRES has been provided by Mrs. Lana R. Hope.

Jan 1, 1976