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By LefTvre Y

In May 1991, AZSA commissioned a new conventional Cell House. This paper focuses on the major improvements introduced in the design and the construction of the equipment, machinery and control. An effective control system together with good reporting and routine operation has resulted in quality control of the Cell House at the highest possible level. Consequently the monthly current efficiency consistently averages above 93 per cent with a total energy usage of 3000 AC kWh/t of cathode zinc. The new concept for the year 2000 and beyond is introduced.

Jan 1, 1993

By E. G. Gaylord

THE material improvements which have been made in the practice of exploiting oil and gas reservoirs in the United States during recent years may be attributed largely to: (1) The necessity for drilling deeper wells at costs not much greater than was formerly expended on shallower wells. (2) The necessity for producing oil at a lower cost per barrel. (3) A growing recognition of the importance of the nature of production practice upon ultimate yield of oil and gas. The first two of these factors result, to a large extent, from the fact that a greater proportion of new development has been deeper development, and these wells have been drilled in the face of progressively lower per well allowables. In California, for instance, maximum allowables have declined from 400 barrels per day in March, 1938, to 156 barrels per day in September, 1940, and during this same period some 125 wells were drilled to the deeper 10,000-foot producing horizons discovered during this time. The third item listed above results from our increasing knowledge of the basic factors which influence the amount of recovery we may expect from reservoirs. In addition to the longer-range planning now being undertaken by the more prudent operators, State proration and conservation laws have focused attention upon the importance of methods conducive to obtaining progressively greater quantities of the hydrocarbons in place. In a paper of this length it will be possible to discuss only a few of the recent advances. An effort has been made to select the more important of these and to indicate, where possible, the factors which have made these advances possible.

Jan 1, 1941

By K. C. Dean

A semiquantitative test for the presence and identification of cesium and rubidium in rocks, clays, and mineral waters has been developed by the Bureau of Mines. The test can be used in the field, as a guide for the prospector, geologist, or mining engineer engaged in location or development [w]ork. It comprises two simple spot tests of a solution prepared from the [m]ineral sample. Phosphomolybdic acid, added to a drop of the test solution, [d]etects cesium, rubidium, and potassium in quantities as low as 60 parts per [m]illion. Silicomolybdic acid, added to a second drop of test solution, enables the operator to distinguish between cesium and/or rubidium and potassium. Test procedures, equipment requirements, and limitations of the method are described in this report. Cesium and rubidium were discovered in 1860 and 1861 by Bunsen and Kirchhoff with a spectroscope. The elements usually occur together, particularly in granite and granitic pegmatites. Rubidium does not occur as an essential constituent of any known mineral, yet it is found as a minor element in so many minerals that rubidium is 16th in abundance in the earth's crust. Cesium, which ranks as the 37th most abundant element, is the principal component of pollucite and a minor element in a wide variety of minerals.

Jan 1, 1960

By A. J. Monhemius

This paper reviews the history of modern iron-control processes in hydrometallurgy. Attention is paid to processes developed in the electrolytic zinc industry for removal of iron from zinc sulfate leach liquors and the problems faced by the industry in the safe disposal of the iron residues produced by these processes. Past lessons learned are projected onto current efforts to develop hydrometallurgical processes for treatment of copper sulfide concentrates. It is argued that any attempt to create a \u201chydrometallurgical copper smelter\u201d will fail, unless methods are developed that can recover iron in a form that can be directly used by the steel or pigment industries.

Jan 1, 2017

By Allen V. Heyl

This old district is a major zinc and lead source and minor copper and barite source. Ores are chiefly in the Galena Dolomite and in limestones and dolomites of the Decorah and Platteville Formations, all of Middle Ordovician age. Locally, deposits have been mined from Lower Ordovician dolomites and Upper Cambrian sandstones. Small deposits of lead, zinc, and iron sulfides have been found in Upper Ordovician Maquoketa Shale and in Lower and Middle Silurian Edgewood, Kankakee, and Hopkinton Formations. No post-Precambrian igneous rocks are known in the region, and the granitic and metasedimentary Precambrian basement rocks unconformably underlie the district at depths of 1500 to 2000 feet. The strata are gently flexed and faulted, probably largely the result of gentle compressive and rotational adjustments in the underlying crystalline basement, especially along lineaments between basement blocks. Folds of three orders ·of magnitude are recognized, and many related reverse, strike-slip, and normal faults of small to moderate displacements are present. Zinc-lead deposits are commonly linear, arcuate, or elliptical in plan. Most ore occurs as vein fillings in fractures and as breccia fillings and lining vugs, but some is in bedded replacements and impregnations of wall rocks. The ore is in shears, small reverse and bedding- plant faults, joints, and solution-slump structures related to intermediate and small folds. The main primary minerals in their general sequence of deposition are quartz, illite, dolomite, pyrite, marcasite, cobaltite(?), sphalerite, galena, chalcopyrite, millerite, barite, and calcite. Wall-rock alterations include solution of the carbonate rocks, silicification, dolomitization, clay alteration, and sanded dolomite. Oxygenisotope, trace-element, lead-isotope, and sphalerite- stratigraphy studies are in progress. Fluid inclusions in sulfide and gangue minerals are filled with concentrated brines at 120° to 40°C. Sulfides are directly replaced by supergene minerals above the water table at 50 to 100 feet in depth. In this relatively cool climate and limestone environment, smithsonite is in pseudomorphs after sphalerite; solution transport and redeposition of supergene minerals are rare. Ore genesis is postulated by rising hot-water solutions-a mixture of heated connate, magmatic, and meteoric waters.

Jan 1, 1968

By Matthew T. Mowry

As the mining industry continues to hire young professionals to supplant the growing number of retirees, a well-developed engineering curriculum, coupled with practical, real-world training, can prepare mining engineering graduates to make meaningful contributions in the industry. Successful companies can be measured not only by their reserve base and annual production but also by their retention of mining engineering graduates with zero to five years of operational experience. My personal experience in the industry during the last five years has been varied and rewarding. The knowledge and experience I have gained have taught me valuable lessons that prepared me for my current role.

Nov 1, 2013

By F. Elgersma

Hydrometallurgical zinc winning processes ?are frequently based on iron containing concentrates which yield a goethite, jarosite or hematite residue. Jarosite or goethite are mostly stored in waste ponds which ,are lined with foil. Water percolating through the pond is withdrawn from the deposit ,and decontaminated before discharge. Despite these measures, more and more pressure is put upon zinc companies to treat their (historical) residues and to produce environmentally acceptable residues. The criterion which determines this acceptability is the potentiality of leaching out hazardous elements by natural processes. This paper provides the comparison of five different process designs for integrated jarosite treatment in a hydrometallurgical zinc winning plant leading to environmentally acceptable residues. The processes are esigned for producing 200 ktons/yr zinc and for treating 80 ktonslyr historical jarosite. Mass and energy balances are used to determme parameters such as: the energy use per ton waste treated and the amount and composition of final residues. The conclusion of the work is that. pyrometallurgical jarosite treatment integrated in hydrometallurgical zinc winning is preferable to hydrometallurgical jarosite treatment. Integrated pyrometallurgical processes lead to a ?smaller quantity of remaining hazardous residues and require less energy.

Jan 1, 1992

By John Mullen

Impingers TWO types of midget impinger apparatus are used at Climax. The Mine Safety Appliances Company's midget impinger (MSA) and the Climax Molybdenum Company's midget impinger (CMC) (Fig. I). The Leiman Brother's No. 25, positive displacement pump is used in the CMC impinger instead of the four-cylinder radial pump that is used in the MSA impinger. With the MSA apparatus it is possible to obtain the proper vacuum by adjusting the needle valve on the vacuum chamber, while with the CMC impinger the proper vacuum is obtained by varying the rate at which the pump is cranked. The Leiman Brother's No. 25 pump is built to displace 0.1 cu. ft. of air per min. when operated at 145 r.p.m. In the CMC impinger this pump is so geared that the required crank speed is approximately 59 r.p.m. Both types of impinger apparatus are equipped with a water gauge mounted on top of the case and they are calibrated and operated in reference to the gauge. The MSA impinger flasks and nozzles are used with both types. Calibrating Impingers A calibrated precision Sargent wet-test meter (Fig. 2) is used in calibrating the impinger apparatus. The apparatus is set up as for taking a sample in the field, except that the hose from the outlet side of the meter is attached to the impinger nozzle. One revolution of the large hand of the meter indicates 0.1 cu. ft. of air displaced. The impinger pump is cranked for one minute, therefore, at a rate that will cause the large hand of the meter to make one revolution. The gauge reading is noted, then the impinger is cranked at this rate for 10 min. and is checked for error. If the meter indicates that more or less than I cu. ft. of air has been displaced, the impinger must be cranked—ither slower or faster according to the error—for another 10 min. and again checked for error. This operation is repeated until the proper gauge reading for a sampling rate of 0.1 cu. ft. per min. has been determined. This gauge reading is used in all sampling operations until the impinger is again calibrated. An impinger is calibrated at least twice each week. MlCROPROJECTOR A Bausch and Lomb model B micro-projector is used (Fig. 3). It consists of a substantial metal base supporting the light source and a microscope. Illumination is provided by a Bausch and Lomb 4.5-amp. arc lamp with mechanical feed. A glass water cell filled with a heat-absorbing and color-filter solution is placed between the arc lamp and the microscope. Two types of solution have been found satisfactory— a 2 per cent solution of copper sulphate or a 2 per cent solution of picric acid and distilled water. This percentage may be varied to give the desired color to the light reflected upon the screen. Any standard microscope may be used. A Bausch and Lomb microscope with

Jan 1, 1946

The following procedure was used to determine cut-off grades: define the orebody profile; plan the stope layout and quantify the work involved; formulate equipment-performance norms; calculate unit costs; input process recoveries and metal prices; and calculate the cut-off grade. Use of the method is illustrated using data from a copper mining complex in India. Results from the study led to the following conclusions for underground mines in general. Cut-off dependent costs vary significantly with the stoping method employed, orebody thickness, the degree of mechanisation and the working efficiencies of the workforce and equipment. This applies even within the same deposit. Sub-level stoping and its variants can be operated at a lower cut-off grade than cut-and-fill and its variants. Thinner orebodies affect cut-off grades adversely, but with thinner orebodies very little further reduction in cut-off grade can be achieved once a certain minimum width has been exceeded. For the same stoping method and in the same mine the cut-off grade varies with the degree of mechanisation. Labour-intensive methods require higher cut-off grades. An allowance for working efficiency should be made when calculating cut-off grades. Higher process recoveries allow a significant lowering of cut-off grades

Jul 1, 1996

By W. O. Crosby

WASHINGTON CAMP, in Santa Cruz county, Arizona, is a small and little known mining district situated on the lower, eastern slope of the Patagonia mountains, about 20 miles east of Nogales and a like distance south of Patagonia Station on the Sonora railroad, which connects it Benson, 83 miles from Nogales, with the main line of the Southern Pacific. This district is also about 4 miles north of the international boundary, 35 miles west of Bisbee and 40 miles north of Cananea, in Sonora. The topography of the district, which lies at a general elevation of 5,500 ft. above the sea, is only very moderately rugged, and presents no obstacles to mining operations. Although some of the claims of the camp, including the Pride of the West, Belmont and Holland, were extensively worked for silver 25 years ago, they passed, at moderate depths, as in so many other districts, out of the argentiferous lead carbonate and sulphide into zinc, copper and iron sulphides; and for two decades the camp was abandoned and almost forgotten. In recent years, however, its apparent possi¬bilities as a copper producer have led to a revival of mining activity; but not, as yet, with conspicuous success. Although economically relatively unimportant, the deposits of Washington Camp are, mineralogically and structurally, nevertheless, typical examples of ore-bodies developed in connection with the garnet ledge now recognized as a normal feature of granite-limestone contacts; and, in the opinion of the writer, this is an instance where a minor example is yet essentially normal and capable of throwing important light upon the origin and genetic relations of the type.

Nov 1, 1905

By Charles D. Litton

An overview of state-of-the-art technology in fire detectors is presented by the Bureau of Mines regarding their use in the mining industry. Detectors are categorized according to the characteristics of a fire to which they respond. Operating principles of the various detectors, their application, and the advantages and disadvantages of each are discussed.

Jan 1, 1979

By A. L. Hornbaker

Colorado has recorded more than 100 years of industrial mineral production. Much of the state's history, culture, and economy is based in mining, but the industrial minerals and construction materials comprising the nonmetallics sector of the industry very often are overlooked or overshadowed by mineral fuels and the metals. Indeed, many of these materials find use in seemingly unimportant industrial applications essential to our economy and life style and yet are not so recognized by the consumer. Unlike many other mineral resources, the numerous industrial minerals occur in many different and often exotic geologic environments, some of which are characteristic only of the western states. In Colorado only a few of these minerals have continued production through the years; many saw only "boom" periods or other critical times of need, such as the world wars. The changing needs and demands of our society in the 1980s will stimulate yet another era of intensive activity in our industrial minerals storehouse. Researchers are finding new uses and applications for these materials in dealing with the energy crisis and fuel shortages, the need to develop domestic mineral reserves of all kinds, and the goals of reuse and recycling. Some of Colorado's little-used and unused industrial minerals hold extraordinary promise in solving some of these problems on the regional and national levels. In this paper we will look at the history of development of Colorado's more prominent nonmetallics and especially at current research on and future potential of several other commodities among which Colorado contains the largest known reserves.

Jan 1, 1980

By R. S. Dean

This report, the second of a series of annual reports of the Metallurgical Division to be released in this form covers the fiscal year July 1, 1935, to June 30, 1936. The technological work of the division is performed by sections. Thus, an efficient organization is provided to prosecute the various problems under investigation, and a logical system is set up for presenting the material contained in this report.

Jan 1, 1937

By MINE SAFETY BOARD

RECOMMENDATIONS OF THE UNITED STATES BUREAU OF MINES ON CERTAIN QUESTIONS OF SAFETY AS OF FEBRUARY 3 , 1933

Jul 1, 1933

By L. M. Scovell

The Internet and its related technologies will radically change the way that mines manage and control their maintenance, repair, and operating supply chains. The Internet is creating new distribution channels and offers new technology platforms with significant advantages over more traditional methods. Mines will have to re-evaluate both the strategies and the tactics employed in these areas. Mines will use e-commerce to integrate their maintenance, repair, and operating supply chains. The integration will extend beyond traditional trading partners to a worldwide network of communities with similar interests and goals. The changes will transform the way mines operate, lower mining costs, and thereby increase their chances of success in an increasingly competitive environment.

Jan 1, 2000

By Fred N. Kissell

This U.S. Bureau of Mines report is a guide for the control of air contaminants during tunnel construction. Topics discussed are calculating air quantity requirements, types of ventilation systems, planning ventilation systems, control of methane gas, control of dust, control of diesel emission, ventilation to remove blasting fumes, measuring airflow, and measuring gases. This report does not provide detailed design information, but seeks to answer practical questions on air contamination issues.

Jan 1, 1995

By Constantine C. Popoff

This report reviews and analyzes, by a simple analytical and logical reasoning, the conventional methods of reserve computations of mineral deposits described in various domestic and foreign publications. It brings together, formulates, and evaluates the principles underlying interpretation of exploration data; and ties such principles to the proposed classification of methods. The material is discussed in sufficient detail to allow general application.

Jan 1, 1966

By K. T. Brashear, N. Ripepi

"Over recent years, specifically following the MINER Act of 2006, an increasing number of manufacturers of underground mine seals in the United States have begun using a form of pumpable cement or shotcrete to create barriers separating the working and abandoned sections of underground coal mines. This seal material, while generally considered to be homogenous and solid, contains a network of microcracks, voids, and delaminations. Generally, it has been assumed that methane (CF4) leakage around these seals is a result of movement around the boundary interface between the seal and surrounding strata. Using a perfluorinated tracer compound, perfluoromethyl-cyclohexane (PMCH), the movement of gases can be monitored through seal material to observe how gases move though the material, both intact and with faulting in the material. This paper documents two large experiments where the movement of PMCH was monitored in the field, along with modeling confirmation using 3D visualization software. INTRODUCTION According to a report in 2007, there were over 14,000 active mine seals in underground U.S. coal mines alone (Zipf, Sapko, & Brune, 2007). These seals are used for both ventilation and safety purposes, to direct the flow of air away from the abandoned area of the mine and to help eliminate the propagation of explosions that can occur on the outby side of the mine seal. The atmosphere on the outby side of these seals typical consists of low levels of methane that have the potential of producing leakage along the face of the seal on the inby side. Methane leakage around mine seals has historically been attributed to the permeability between the seal and mine interface (McPherson, 1993). According to the United States Bureau of Labor Statistics (BLS) between 2003 and 2012 an average of 17 deaths occurred annually in underground bituminous coals mines. The only time during the ten-year period where the fatalities were higher than the average was in 2006 and 2010, years which had three major explosions occurring in underground coal mines in West Virginia and Kentucky. Two of the explosions were propagated through the mine by seal failure or methane leakage around newly poured seals (Light, et al., 2007) (Gates, et al., 2006). These recent events, and new regulations regarding seal strength (MINER Act), have created a need to monitor the condition of underground mine seals. BACKGROUND Measuring the permeability of solid materials, such as concrete or seal materials, can be a valuable tool in the field of non-destructible testing (NDT). By using an inert gas, such as nitrogen, injecting the gas into a solid structure, and measuring the resultant flow rate and pressure differential, this can provide valuable information about the structure. Studies have shown permeability can be affected by the stresses applied to the structure, as well as temperature and moisture (Choinska, Khelidj, Chatzigeorgious, & Pijaudier-Cabot, 2007) (Abbas, Carcasses, & Olliver, 1999)."

Jan 1, 2015

By A Bird

Gravity gold circuits have an important part in reducing operating costs and maximising recovery in modern gold plants where coarse gold is present in the ore body. The design and selection of equipment has a vital part in the overall effectiveness of the gravity gold circuit. There are a number of associated factors that need to be taken into consideration when selecting the most suitable equipment for gravity gold circuits including occupational health and safety, security and labour requirements. This paper is a case study that outlines the validation behind the design, selection of equipment and subsequent benefits of the recent upgrade of the gravity circuit at the Marvel Loch gold mine with the main component to the upgrade being the installation of a Consep Acacia Reactor. Since the upgrade there has been a significant increase in gravity recovery, which has reduced the amount of gold reporting to the leaching circuit therefore reducing reagent consumption and overall operating costs. There has been an increase in overall gold recovery and therefore increased gold production. The benefits to occupational health and safety include the removal of toxic gases being released in the gold room during the previous practice of gold concentrate calcination and the removal of the arsenic and nickel from the gold doré, which poses a risk during refining. Manual handling and security has improved as there is no physical contact with gold concentrates during the automated process using the Acacia reactor. The total time for gold room personnel working in the gold room has also reduced from around six hours per day to less than one hour per day.With the continuing development of low grade gold deposits, there will be an increase in demand for low capital, high recovery gravity gold circuits that can significantly increase overall production while reducing operating costs.

Aug 8, 2011

By E. J. Gleim

In April 1932, the Bureau of Mines published Information Circular 6595, entitled "Data in Reference to Installation of Cables in Shafts and Boreholes", in which were described methods followed in various sections of the United States when electrical circuits are taken into mines by means of cables suspended in shafts and boreholes. In view of the present tendency to extend high-tension cables along entries and passageways from the bottom of the shaft, borehole, or other point of entrance to coal mines rather than over the surface, it is deemed that the various methods of installing such cables deserve careful consideration, particularly in mines in which gas and coal dust contribute to explosion hazards. This is especially true of localities where there is an inclination to restrict the extension of 2,300- and 4,000-volt circuits into the mines. Probably it is feared that accidental contact with the cables of such circuits may result in more serious shock than with lower voltages; also, it is possible that new circuits are regarded merely as explosion hazards additional to those already existing, regardless of the manner in which the new circuits may be installed. It is the firm belief of some engineers that the circuits can be installed so that they will not be damaged by wrecks or roof falls, thereby eliminating the hazard of explosion from this source while at the same time making the chance of accidental contact remote if not impossible. Moreover, some believe that fire hazards from direct-current systems can be reduced by keeping motor-generator sets close to load centers. Thus, although the alternating-current circuits would be lengthened, the size and extent of direct-current circuits would be kept to a minimum.

Jan 1, 1939