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By Ana Chiquini, Clayton V. Deutsch

The most common approach used in the mining industry for mineral resources modeling is to estimate the grades using ordinary kriging and report the recoverable resources based on this deterministic estimated model. Mineral resources calculated with kriging are a smooth representation of the actual distribution of grades and do not provide an assessment of uncertainty. Unlike kriging, simulation reproduces the variability of the grades in the mineral deposit and provides an assessment of uncertainty. Reporting mineral resources directly on high-resolution simulation results would assume perfect knowledge of the grade at the time of mining and selectivity at the scale of the data. There will always be uncertainty left at the time of mining, so assuming perfect knowledge of the grade in the future is incorrect. There are two concerns when geostatistical simulation is used for resources modeling: the information and the mining selectivity effects. A new framework for resource estimation is proposed with two separate modules to address those concerns. The information effect is accounted for by anticipating the additional production data that will be available at the time mining to guide the destination for the mined material. The mining selectivity effect is addressed by mimicking the grade control procedure to get mineable dig limits at a chosen selectivity, represented by a minimum mineable unit size. In addition to a prediction of recoverable resources that will be closer to the material mined in the future, the framework proposed provides an assessment of local and global uncertainty for risk management.

May 26, 2020

By C. W. Van Law

WE have just heard a very able presentation, by Mr. J. C. Cameron, on the subject of Recent Trends in Labour Relations, as they exist today in Canada (l). With minor changes, what he said applies equally to the situation in the United States. Direct negotiation between employer and employee on a man-to-man basis, wherein good faith and mutual esteem was at least sometimes a factor, has almost entirely given way to a mass struggle in which each side is represented by highly trained specialists in a new jurisprudence, built up on vote-getting labour laws, decisions in analogous cases by Boards whose members may have had very little personal acquaintance with the specific case, etc., etc. Membership in a labour union has become almost an essential requisite to a job; once in, the individual workman loses his identity and dares not act on his own initiative or even express any idea not handed him by his Union head. An honest workman cannot turn in an honest day's work, because his Union will not allow him. Leadership in the Unions has become so powerful an instrument, both politically and monetarily, that Union policies are drafted primarily to build up that power, and may have little relation to the equities of the individual case. ?While both sides still render lip-service to the doctrine that Capital and Labour can advance best by co-operation to mutual benefit, that doctrine has in effect given way to as bitter and as legalistic a struggle as any in our civil courts. There are many reasons to believe that we are, industrially, in a situation much like the European situation from 1935 to 1939; an impending war to the death with 'appeasement' as the only, unavailing, policy

Jan 1, 1945

The Aluminum Company of America (Alcoa) announced plans to shut down production at the remaining two potlines at its Point Comfort, Texas primary aluminum smelter due to the increased costs of natural gas. Total capacity of the facility, which had been partially closed since 1976, was 185,000 tons per year representing 3.6 percent of current capacity in the United States. There were practically no price movements in March on 99.5 percent aluminum ingot, with producers at 53¢ per pound and dealers, 48¢-48.5¢. BISMUTH The March selling position of U.S. producer metal was held at $3.50 per pound. In contrast, east coast dealers and traders adjusted their quotes from $2.55-$2.60 to a wider range of $2.40-$2.60.

Jan 1, 1978

By R. W. Raymond

On the Manchuria. SOMEWHAT fatigued with excess of enjoyment and strenuous continuity of movement on the trip to and through California, the members and guests of the Institute party embarked Tuesday, Oct. 17, on the Pacific Mail S. S. Manchuria for a further journey to and through Japan. The good ship displayed the flag of the Institute (blue cross-hammers on a white ground), together with the Stars and Stripes and the ensign of the company. Uninterrupted fair weather and smooth water attended the passage to Honolulu. The Manchuria proved herself most commodious, comfortable and clean ("A sweeter steamship never sailed," quoth President Hunt) ; Captain Dixon and his officers were most agreeable, as well as most efficient; the passenger list comprised many congenial people besides ourselves-among them a score of missionary folk, and also Mr. M. H. de Young, Vice-President of the Panama

Jan 1, 1912

A unity of viewpoint emerged from the workshop. The concept that transmission is via characteristic modes was a common theme in many of the presentations. Also, the confusion an the meaning of monofilar and bifilar to describe these dominant modes was cleared up. But, there was still a healthy divergence of opinion on what constitutes an optimum system. It was generally agreed that further analytical and experimental work is definitely needed. In particular, it was stressed that independent measurements of the constitutive properties of the electromagnetic environment are needed. Also, there was considerable concern that laboratory measurements of rock samples could lead to misleading results for the effective conductivities. Also, there was a general recognition that over simplified propagation theory should not be used to interpret field data. From a theoratical and practical point of view, it was realized that mode coupling plays a vital role in the transmission channel. One must not only understand which and how many propagation modes are excited by the transmitting antenna, but the conversion of energy from one mode type to another must be accounted for. This conversion can either be done intentionally (by fixed mode convertors) or non intentionally (by random wall roughness). In fact, mode conversion can be quite complicated when various propagation paths exist such as when insulated cables, leaky feeders, grounded rails, coal seams, etc. all convey portions of the electromagnetic energy. However, this state of affairs should be regared as an. opportunity for extended communication coverage in mines rather than a limitation of a desig. procedure based on preconceived notions of the dominant propagation mechanism.

Jan 1, 1978

According to reports in August, Botswana RST's copper- nickel-cobalt smelter at Selebi-Pikwe produced 7 percent above the rated capacity of about 3,500 metric tons of matte per month. This record production occurred after 2 years of plant production difficulties and was brought about by a new management team. A shutdown for furnace maintenance had been planned for this year, but was postponed because of the improvements in production and operations. However, the mining operation continued to face problems relating to higher costs and some outstanding claims. COPPER: Effective December 1, ASARCO, Inc. and Phelps Dodge Corp. reduced their domestic copper prices by 54 per pound. Within a period of 3 days, a11 other producers (Kennecott Copper Corp., Newmont Mining Corp., Cities Service Co. , Copper Range Co. , Duval Corp., and Inspiration Consolidated Copper Go. ) had either lowered or discounted their market postings by 5¢ to 65.625¢ per pound on electrolytic wirebar and 65$ on cathode plate. Between November 29 and December 3, New York merchants decreased wirebar quotations by 1.8¢-2¢ to within a range of 57.8¢-58¢ per pound. New York Commodity Exchange (COMEX) spot-contracted copper in the week was priced at 57. 1¢ on Monday, 56.7¢ on Wednesday and Thursday, and 57.4¢ on Friday, resulting in a 5-day average of 56.9¢, London Metal Exchange (LME) cash (prompt) wirebar averaged 56.3¢ last week, opening Monday at 56.6¢, falling from Tuesday?s high of 57.2¢ to Wednesday?s low of 55.6¢ and closing Friday at 56.1¢. Foreign producers, guided by LME market transactions, lowered wirebar quotes to 56¢ per pound. Copper stocks as of December 3 totaled 187,702 short tons at COMEX warehouses and 654,573 tons at LME depositories, compared to 97,413 and 537,481 tons, respectively, for the corresponding 1975 period.

Jan 1, 1976

Electric power curtailments resulting from the coal strike, required Noranda Aluminum, Inc. to shut down its 140,000 ton-per-year (tpy) primary aluminum smelter at New Madrid, Mo., and layoff 308 workers. Other primary aluminum production facilities affected by the coal strike included the Aluminum Company of America plant at Evansville, Ind. which shut down half of one potline; the Eastalco Aluminum Co., smelter at Frederick, Md., which cut production by 7 percent; and the National-Southwire Aluminum Co. plant at Hawesville, Ky. which cut production by 6 percent. Alumax, Inc. announced that construction had started on a 91,000 tpy potline at the Eastalco primary aluminum smelter. The new potline will be owned 65 percent by Alumax and 35 percent by Mitsui & Co. Ltd. Howmet Aluminum Corp., which currently owns 50 percent of the existing 176,000 tpy facility, has the option of becoming a 50 percent owner of the third potline in 1982. Construction of the new line was scheduled to be completed in 1980.

Jan 1, 1978

By L. BENEDICT

COMMENTING on the report of the latest Royal Commission for India, the September, 1926, issue of the National City Bank's monthly letter states, among other things, that "The decision of the Royal Commission is against the proposal for a gold coinage, but in favor of placing the silver coins and paper currency now redeemable in silver on a gold basis." Also, it quotes the following from the Royal Commission's report: The essence of the proposal * * * * * is that the ordinary medium of circulation in India should remain as at present the currency note and the silver rupee, and that the stability of the currency in terms of gold should be secured by making the currency directly convertible into gold for all purposes, but the gold should not circulate as money. It must not circulate at first, and it need not circulate ever. In this connection it may be stated that during the last one hundred and fifty years or so unsuccessful attempts have been made by the governments of different nations of the world to devise a plan or plans by which gold and silver could be used concurrently for money purposes and, particularly, as standard money; such, for example, as bimetallism, which, of course, is impracticable. But, since none of such plans has been adopted generally it is logical to conclude that their proponents did not shape them so as to conform to the basic principle of standard money, or else political issues were deemed to be dominant, or, perhaps, it was partly due to each.

Jan 1, 1926

By Charles W. Merrill

AN ADEQUATE, dependable, and continuing supply of raw materials is indispensable to tile the United States and its industries in meeting the needs of an expanding Population, a rising standard of living, and the national security. The primary responsibility for appraising the status of the country's mineral supply and for making appropriate recommendations within the executive branch and to the Congress has been pinned in the U.S. Department of the Interior. In fulfilling its role of governmental responsibility for raw-material supplies and their efficient utilization, the Bureau of Mines has analyzed the factors in current and future mineral supplies and demands and has developed 87 statements for specific commodities that assess the national position and problems for these metals, minerals, and mineral fuels. These statements, which constitute the chapters of this volume, are based on lire assumption that nearly till production and consumption of materials in the United States are to be by private individuals and organizations, in accordance with the Nation's devotion to a private-enterprise economy.

Jan 1, 1960

By Wendell L. Reich

Percussion drilling dates back to the hand operated star drill and hammer. Eventually steam and compressed air were substituted for muscle power and the mechanical percussion drill was born. From the hand held jack hammers, driving a forged steel bit into the rock, there evolved the jack leg, the rubber tired and crawler mounted drill carrier with automatic feed, increasing power and reducing man?s muscle requirements. Because the reaction of a blow on one end of a piece of steel has to be transmitted to the other end there is a limit to the depth or length of drill steel that can economically be used in out of the hole percussion devices. During the late 1800?s there is evidence that designers were attempting to put the percussion tool at the bottom of the hole, directly on the bit, in order to avoid the long drill steel which absorbed much of the blow, leaving little to be applied to the bit and the rock being drilled.

Jan 1, 1972

By Paul T. Allsman, William H. King

This paper describes the mineral deposits and discusses mining and milling methods and related operating conditions in an important gold , silver , lead , and zinc producing area in Ouray , San Juan , and San Miguel Counties , Colo . , embracing 250 square miles . The area is extremely rigged , ranging in altitude from 8,000 to 14,000 feet . White men first penetrated the area in 1860 , when a group known as "Baker's party " reached the Animas River at the present site of Silverton . Difficulty with the Ute Indians and severe winter conditions forced the group to leave and discouraged prospecting until 1870 when a second party reached the area and succeeded in producing 27 tons of ore yielding $ 150 a ton in gold . In 1874 , a treaty with the Indians opened the way for settlement , and mining was established . The total production of recovered gold , silver , copper , lead , and zinc from 1873 to 1947 in the three counties is valued at $347,057,047 . The greatest amount of the total production of metals has come from quartz veins in a series of volcanic flows and tuffs covering the area and comprising a blanket 4,000 to 6,000 feet thick . The igneous rocks were laid down upon an old , erosion surface and are underlain by Paleozoic and Mesozoic sedimentary rocks and pre - Cambrian metamorphic rocks . The entire series has been intruded in late Tertiary time by volcanic dikes and larger intrusive masses . Because of the great differences in relief generally , mining is con-" ducted through long adits to a depth of nearly 3,000 feet below surface in places . Walls of the veins generally stand well , and shrinkage stoping is the most common method of mining . As virtually all of the ore is sulfide below the zone of oxidation , flotation is the common method of milling . Generally , where gold is important , provision is made for its removal by jigs . Bulk concentration of the sulfides is practiced at smaller mills , but the larger operations make a selective lead and zinc concentrate or a lead , zinc , and copper . concentrate . ·

Mar 1, 1950

By J. J. Forbes

Problems connected with the incidence, effects, determination, and control of dusts are still much before the public, although more information is available to the layman than when Bulletin 400, of which this publication is a revision,5 was issued in 1937. Bulletin 400 attempted to assemble information in convenient form on various phases of the dust problem, largely in the mining and allied industries. This revision includes data that have accumulated since 1937 and some that appeared previous thereto but were not available to the authors at that time. The literature on this subject is so voluminous that no attempt has been made to include all published material or all types of dust diseases, but only to assemble some of the more outstanding data on several aspects of the subject.

Jan 1, 1950

During the period January 1, 1977 through July 31, 1977, 5 percent (264,000 tons) of U.S. capacity was closed due to power curtailments in the Pacific Northwest because of the shortage of water. During July, one plant in Tennessee cut production by 50,000 tons annually due to a power reduction by the Tennessee Valley Authority. Full capacity production was resumed at a West Virginia smelter during September. If demand for aluminum is strong it seems likely that aluminum supply during the remainder of 1977 and in 1978 will be tight. The price was increased 3¢ per pound to 51¢ per pound effective March 28, 1977, and by an additional 2¢ per pound to 53¢ per pound, effective July 5, 1977. New projects and expansion of existing facilities are planned by Australian aluminum companies over the next 2 to 3 years. The companies listed have committed themselves to spending approximately A$801 million: Alcoa of Australia Ltd. -New alumina plant at Wagerup, south of Perth. Darling Ranges bauxite is located near the proposed project. A$650 million. Coma 1 co Industries Pty. Ltd. -Increase bauxite mining capacity and upgrade or replace other facilities at its Weipa mines on Cape York Peninsula region of Northern Queensland. A$81 million. Alcan Australia Ltd. -Expansion program that will increase capacity of the Kurri Kurri aluminum smelter north of Sydney about 50 percent, and improvement of other facilities at the plant. A$70 million.

Jan 1, 1977

The revised estimate of coal production in January 1977, is 39 million tons -- down 12 mi 11 ion tons compared with production in January of last year, largely as a consequence of the snow storms and cold. The major coal-hauling railroads operating in Eastern and Midwestern States reported to the Bureau of Mines that they loaded approximately the same number of cars for the week ended February 5, as in the preceding week. The Bureau of Mines estimates that U.S. coal production for the week ending February 5, 1977, was approximately 8.5 million tons, or nearly 3.5 million tons less than production for the corresponding week in 1976. Coal production from January 1 - February 5, 1977, was approximately 47.8 mi 11 ion tons compared with production of 63.5 million tons for the corresponding period in 1976. As of the first week in February, river and truck shipments of coal in the Eastern U.S. were about one-half of the normal traffic. Despite the freezing weather and ice and snow conditions of rivers and highways and reduced rail shipments, there was reportedly little or no shortage in coal supply to consumers. Inventories at electric utility plants and steel company coke plants at the beginning of the severe weather were sufficient in most cases for at least 30 days" operations. There have been no reports of coal shortages at other industrial plants.

Jan 1, 1977

By David J. Hoadley

This report describes the development and limited testing of a semi-automatic, raise climber, Compact Service Hoist System designed for stope access in underground metal and nonmetal mines. Demonstrated capabilities of the system include a 1,000-lb payload capacity, control from the traveling cage and from up to three remote stations, operating in vertical or inclined raises 3 ft in diameter and up to 300 ft in length and a travel speed of 50 ft/min. The system has the capability of operating in crooked raises because the conveyance climbs two stationary wire ropes suspended down the raise. The drive unit is electrically powered with power and control signals supplied to the drive unit through an umbilical 'cable also suspended down the raise. The system has been designed for portability, ease of installation and minimum raise development. The hoist has been demonstrated successfully in an above ground test tower. This report provides a detailed description of the hoist design and its demonstrated performance to date.

Jan 1, 1985

By R. T. C. Rasmussen

"INTRODUCTION The primary purpose of the Bureau of Mines electrolytic manganese pilot plant at Boulder City, Nev., is to improve the Bureau-invented electrowinning process and to determine the applicability of the process to the extensive domestic low-grade manganese ores with a view to making the United States dependent upon foreign sources of manganese. 3/4/ Incidental to accomplishing this purpose, the pilot plant has produced a substantive quantity of electrorytic manganese since the start of operations late in 1941; present cabacity about 1 ton a day of manganese metal. A second important purpose of the pilot plant is the supplying of electrolytic manganese for full-scale tests in cooperation with industrial users of manganese.The Rustless Iron& Steel Corp., Baltimore, Md., was the first steel company to cooperate with the Bureau of Mines in large-scale testing of electrolytic manganese. Arrangements were made with C. E. Tuttle, then president of the corporation, whereby the Bureau would supply electrolytic manganese to make a sufficient number of full-scale stainless-steel heats to demonstrate thoroughly its merits as a replacement for low-carbon ferro-manganese in the corporation's stainless-steel practice. The corporation's purpose in the investigation was to determine the possible advantages of electrolytic manganese resulting from its almost complete lack of phosphorus and caroon that might offset its then considerably higher cost per unit of manganese than low-carbon ferromanganese. The data presented herein are based upon reports of A. L. Field, technical director, and L. Weitzenkern, research engineer of Rustless Iron & Steel Corp.; they are supplemented by observation of the author who visited the plant during the tests."

Oct 1, 1945

By Enzo Palumbo, Joël P. T. Kapusta, François Larouche

In light of the rapid deployment of bottom blowing smelting in China over the last ten years, one has to wonder why it has taken the copper industry so long to adopt ultra-high oxygen enrichment via Savard-Lee type injectors. As early as 1976, Kellogg and Henderson suggested, in their landmark paper on energy usage in the copper industry, that ‘maximum use of oxygen enrichment of process air’ was one of seven ‘energy saving features’ for copper matte smelting and converting. Yet today, shrouded injection and high oxygen enrichment has not been implemented in copper bath smelting outside China and Vietnam. In this paper, the authors explore the reasons why bath smelting processes such as the Noranda Reactor and the Teniente Converter still operate around 40% oxygen enrichment, while the bottom blowing SKS/BBS process typically runs at 65 to 75% oxygen, with all three processes producing white metal. Are there fundamental metallurgical explanations for this striking difference beyond the long-standing skepticism towards high oxygen shrouded injection and its perceived high implementation cost?

Jan 1, 2015

This report describes Phase I of the project --Development of a Mechanized Scaler --performed by Battelle, Pacific Northwest Laboratories for the U.S. Bureau of Mines. The objectives of Phase I were to 1) assess the needs of the industry as related to mechanized scaling; 2) conceive, evaluate and select mechanized scaler concepts; and 3) prepare preliminary designs of the selected machine concepts. To assess the scaling needs of the industry, we reviewed both U.S. and foreign literature, evaluated U.S. scaling accident statistics, reviewed existing mechanized scaling equipment, performed a series of mine visits and telephone interviews with mine operators, and assessed the applicability of a loose-rock detection system. The literature review identified over 25 scaler-related articles. However, little of the information could be used directly in the conceptualization and design portions of the project. Three articles did supply information on a number of machines used in Europe, along with statistics describing their effect on mine safety. For example, the French reported a 50% reduction in the total number of scaling-related accidents and a full 80% reduction in the number of lost-time injuries in the Lorraine mining district.

Jan 1, 1981

By Keith L. Harris

Real2 gross national product (GNP) grew at a seasonally adjusted annual rate of 1.3% in the fourth quarter and at 2.5% for all of 1986, according to the most recent Department of Commerce estimates table 1). The 1986 GNP growth was the lowest since the recession in 1982, and was slightly below the estimate published in the last issue of Minerals and Materials. Barriers to greater economic growth in 1986 included the Federal budget deficit, the trade deficit, reduced energy-sector investment because of low oil prices, and uncertainty over changes in the Federal tax code.3 Major sectors of the economy responsible for the fourth-quarter growth included real Government purchases of goods and services, up $19.9 billion from the third-quarter level; real net exports, up $12.2 billion; real residential investment, up $3.0 billion; and nonresidential fixed investment, up $1.5 billion. The increase in Government purchases of goods and services was attributed to the S25.1 billion rise in net purchases of farm products by the Commodity Credit Corp-oration. Real personal consumption expenditures and inventory investment declined, however. Personal consumption expenditures declined primarily because of reduced motor vehicle purchases. Despite only modest growth during the fourth quarter, the economy improved significantly because of the narrowing of the trade deficit and growing employment (table 2) while maintaining low unemployment and inflation rates. Business sounded an optimistic note, with planned increases in current-dollar capital spending of 0.9% for 1987 compared with a 1.7% decrease in 1986. While it is primarily the nonmanufacturing industries that expect to increase investment from 1986 levels, some manufacturing industries are increasing investment by significant percentages as well, notably the steelmaking and nonferrous metals industries (table 3).

Jan 1, 1987

By Charles D. Walcott

Jan 1, 1901