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By W. F. Visser

The growing availability of information and data analysis capabilities provides new opportunities for improving the performance of operations. By using real-time measurements and artificial intelligence, it is possible to respond faster to changing conditions, while accurate and timely information permits the rapid evaluation of changes and fast business improvement decisions. This paper presents a blueprint for system alignment, organizational design and management practices to leverage these developments in performance-driven operations management in mining and mineral processing.

By Angelus S. C. Owili-Eger

The investigation into the hydrologic and hydrogeochemical influence of longwall coal mining in the Appalachian coal basin was under- taken in response to the need to technically address problems of damaged or impaired well yields, and quality deterioration. Prior to this study, issues regarding reduced aquifer yields and degraded water quality had to be handled in a very qualitative manner. Such an approach would, in the long run, claim a heavy toll on the mining industry. The primary objective of this undertaking, therefore, was to provide sufficient and reliable information base for the determination of the local and possibly the regional effects of longwall mining on well yields, and the hydraulic and hydrogeochemical parameters of the immediate surface and subsurface water systems. Specifically, the program was designed to supply definitive data to answer the following series of questions: 1. Does longwall mining affect the quantity and quality of water in local wells above and adjacent to longwall panels and barrier pillars? 2. If the water quality is affected as soon as mining takes place, does it heal? or if it is not affected immediately, does it change over a longer period of time? 3. How do the aquifer water transmitting characteristics respond to induced physical ad hydrologic variations? 4. What is the extent of the various changes in quantity and quality of the water resources? 5. Should and can standard hydrologic evaluation techniques be used to determine the hydraulic properties of highly fractured zones located within a larger and less permeable aquifer?

Jan 1, 1983

By N. Ripepi

"The Langmuir model has been widely used for the coal-methane sorption process via an isothermal test. However, even though the temperature-dependent Langmuir model were recognized theoretically and experimentally, the quantitative relationship between the Langmuir’s constants (a & b) and temperature have not been clarified and confirmed by lab test data. This paper collects 158 methane-coal sorption data under different temperatures, which apply the Langmuir model to consider the relationship between Langmuir’s constants (a & b) and temperature (see APPENDIX I). Even though the Langmuir model cannot be used to show the physical state of methane adsorption on coal, it is widely used because of its simplicity and the reasonable explanation of its parameters (a & b). The results from these published isothermal tests confirm that 1) there is no consistent relationship between Langmuir’s constant-a and temperature; 2) the Langmuir model is a temperature-dependent model, and the temperature-dependent feature is mainly shown by the relationship between Langmuir’s constant-b and temperature; 3) The relationship between Langmuir’s constant-b and temperature can be described by both the exponential and linear relationship with dried coal. This paper provides a database for temperature-dependent Langmuir’s model, which can be used for reservoir simulation of coalbed methane reservoir, coal seam degasification modeling for underground coal mines considering the heating effect induced by geotherm and heat injection (via hot water, hot steam, ultrasonic, etc.). INTRODUCTION The isothermal test for gas sorption on coal is one of the fundamental tests in Coalbed Methane (CBM) recovery fields, such as underground coal mine methane degasification, CBM gas-in-place estimation, and carbon dioxide sequestration in un-minable coal seams. Generally, two methods, volumetric and gravimetric, are employed to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012). Based on these two approaches, a series of commercial and self-assembled instruments are built and several calculation methods are used to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012, Gasparik, K., 2014; Goodman, A. L., et al, 2004; Zhang, L., et al, 2013). In the post-processing stage, many models are provided to analyze isothermal data in order to understand the storage mechanism of gas in coal. Common models include the Langmuir model (and its extended forms), the pore-filling model, multilayer adsorption model (BET), and the Gibbs’ model. Among these models, the Langmuir model is the most widely used for its simplicity and functionality. The Langmuir model is expressed as follows:"

Jan 1, 2016

The effects of additives, sodium hydroxide, sodium carbonate, sodium oleate, oleic acid and polyacrylic acid, on stirred media milling of limestone have been investigated. The results are evaluated in terms of specific surface area, specific energy and energy efficiency as a function of additive dosage, polymer molecular weight, solids concentration and relevant operating variables. Use of additives generally results in changes in specific surface area and energy efficiency, while under certain conditions a more than 100% increase in these parameters can occur. Relevant interfacial properties have been measured and milling mechanisms involved are explored particularly in terms of the effect of additives on the flow patterns at higher solids concentration.

Jan 1, 1996

By R. Herrera-Urbina

Measurements of the electrophoretic mobility of bastnaesite in aqueous solutions of sodium nitrate reveal that the isoelectric point (iep) of this cerium fluocarbonate occurs at about pH 9.3. These results also indicate that the pH affects significantly the electrophoretic mobility of bastnaesite, which becomes more positive as the pH decreases and more negative as the pH increases from the iep. Computations of solid-solution equilibria for the bastnaesite-H2O system closed to the atmosphere as a function of pH indicate that cerium fluoride precipitates in acidic solutions, whereas cerium hydroxide precipitates in alkaline solutions. When the initial amount of bastnaesite is fixed at 0.05 wt.% (the solids concentration used for electrokinetic experiments), these computations reveal that bastnaesite is the only solid phase in the pH range from 5.75 to 8.55, it coexists with CeF3(s) between pH 5.22 and pH 5.74, and with Ce(OH)3(s) between pH 8.56 and pH 10.12. Cerium fluoride and cerium hydroxide are the only solid phase below pH 5.2 and above pH 10.2, respectively. According to these computations, the dissolution-precipitation processes that occur when bastnaesite is equilibrated in aqueous solutions at different pH values determine the solid phases present in the system. In turn, these processes must affect the electrokinetic potential at the solid-solution interface, and they must be considered for explaining electrokinetic measurements as a function of pH when bastnaesite is the original solid phase in aqueous suspensions.

By Archie M. Richardson, Carl E. Brechtel, Tom R. Kelly, Frank Feero

Recent work to upgrade the ventilation system for the el Mochito lead/zinc mine in central Honduras is discussed. Network modeling and underground measurements were used to evaluate cost-effective alternatives for achieving satisfactory ventilation in a complex and expanding underground operation. Both interim and long-term solutions were implemented to make mining possible under difficult conditions. INTRODUCTION Mining operations at the el Mochito Mine, located in the central highlands of Honduras, Central America, have been virtually continuous since the opening of the mine in 1948. Initially a high-grade silver mine, the mine has expanded along a westward trend of pipe-like orebodies to a distance of roughly one mile from two centrally located shafts. Production of the relatively large San Juan orebody at the western most extension of the mine (Paddock, 1981) led to the introduction of diesel-powered equipment; however, the ventilation infrastructure was insufficient to meet the needs of mechanized mining. A succession of owners/operators in the 1980s allowed the existing ventilation infrastructure to decay to the point that ventilation in the production areas of the mine was very poor. Environmental conditions in some working areas were not conducive to efficient ore extraction because of high dry bulb temperature, high humidity, and diesel emissions. Upon acquiring the mine in 1990, Breakwater Resources of Tucson, Arizona began an aggressive program to refurbish the mine infrastructure to complete extraction of the San Juan orebody and to allow the extension of the mine another 2500 ft to the west for extraction of the Nacional orebody. The program included increasing the capacity of the main ventilation system. This article presents a case history of the process of upgrading the ventilation system in a mine where extensive old workings cause large air leakage. This process has been one of selecting solutions to difficult technical problems that are compatible with the existing mine infrastructure and economic constraints. The initial ventilation system is described in the background section, along with ventilation projections for the mine expansion. Field characterization of the ventilation system for design verification and fan specification is then discussed. The paper describes a series of interim changes to the system to improve ventilation pending completion of new ventilation boreholes. In addition, the temperature/ heat problems in the mine are described. BACKGROUND Initial Condition of Ventilation System The ventilation system is illustrated in Figure 1, which shows the extent of mining with the main ventilation paths superimposed. Early mining around the two shafts opened up vertical connections (stopes and raises) over the entire 2420 ft (737.6 m) of vertical extent, and mining progressed to the west primarily using compressed air and electric-powered equipment. Since ventilation was not a complex problem in the original mining system, the stopes and interconnecting raises were not sealed. The San Juan orebody was much larger than the silver ore zones mined previously, being primarily zinc and other base metals. Its geometry, size, and grade allowed the use of vertical crater retreat (VCR) stoping with diesel mucking and haulage equipment. Its depth, along with the existence of warm groundwater, resulted in a mine climate problem on the lower levels. To establish a complete ventilation circuit, two vertical boreholes (Bonanza Nos. 1 and 2) had been drilled by previous owners from the surface in the vicinity of the San Juan orebody. The system design called for air to be drawn down the intake shafts, across the lower mine levels to the San Juan workings, then up through the San Juan ramps and ore passes to these two exhaust boreholes (see Figure 1). In practice, however, only the Bonanza No. 1 borehole was drawing air through the desired path. Leakage across the old upper levels from the intake shafts, the Caliche tunnel, and from intervening abandoned stopes and raises supplied most of the air flowing to the base of the Bonanza No. 2 borehole. In effect, there were two ventilation circuits in semi-parallel through the mine, of which only one was delivering appreciable air to the San Juan workings.

Jan 1, 1993

By Thomas E. Ban

D-LM at Mobile The qualified success of iron ore pelletizing processes has influenced considerations for production of highly beneficiated fur¬nace charges. Such beneficiation would necessarily involve some forms of chemical and perhaps thermal conversion for production of prereduced pellets, preheated pellets, precalcined pellets, and perhaps pellets which contain all of the above features as preheated, prereduced, precalcined products. This type of furnace burden will be adapted within a new ironmaking process to be activated commer¬cially during the latter part of 196$ in Mobile, Alabama. This process will integrate a new pelletizing system with an electric smelting furnace and the pellets will be comprised of a composite charge blended from metallurgical proportions of iron ore, coal, and limestone. The plant as designed and constructed by McDowell¬-Wellman Engineering Company will feature the D-LM process and will be owned by McWane Cast Iron Pipe Company. It is significant to

Jan 1, 1968

By Sheldon P. Wimpfen

Back in 1970 Congress passed the National Mining and Minerals policy Act, which had as one of its basic tenets to rely on a strong and stable private minerals industry for the development and production of our mineral resources. Since then, a substantial amount of legislation has been introduced that impacts on the minerals industry. Although most of the bills proposed are not passed into law, each bill affecting minerals and mining is given careful review by the Bureau of Mines. Comment is forwarded with the object of being helpful to legislators by providing our assessment of the probable impact of each bill proposed along with suggestions to improve them. Actually few bills introduced become law. For example, in the 93rd Congress 4,260 bills were introduced in the Senate and 17,690 in the House. In the final accounting there were passed 123 private laws and 649 public, 3 percent of the bills introduced. There would be little merit here in attempting to analyze each mineral-related bill that was proposed. Many are similar and aim at making a certain aspect of our minerals activity fit needs. So, to simplify the task the many bills have been grouped by subjects. Slide 1 shows the principal topics and the number of related bills introduced. Putting it altogether, there are 26 principal subjects and almost 200 bills. And these numbers are probably off somewhat, as this accounting was made early in December.

Jan 1, 1976

By L. M. Cenegy

The formation of scale is common in gold ore processing plants. A working definition of scale, applicable to the various scaling conditions found in gold ore processing plants, would be: "a hard, tightly adhering deposit formed in place by the precipitation of calcium-bearing mineral compounds from water". The most common scale found in gold processing plants is calcium carbonate (CaCO3) although calcium sulfate (CaSO4) is occasionally a problem.

Jan 1, 1990

By Z. R. Llanos

The petroleum refining industry makes extensive use of catalysts for the conversion of crude oils into more usable products such as gasoline, fuel oil and gas, aromatics, and others. Catalysts used for hydraprocessing contain cobalt-molybdenum or nickel -molybdenum, although there are catalysts that also contain tungsten. During hydroprocessing, nickel and vanadium are deposited on the catalysts, eventually rendering them inactive. The refiners are then confronted with the problem of disposing the spent catalysts. In the past, landfilling was a common method of disposal and it is still practiced in some countries. Other refiners prefer to stockpile the spent catalysts at the refineries until the price of metals warrants their sale to metal reclaimers. This practice, however, poses environmental problems to the refineries for storage and disposal of spent catalysts. Other types of catalysts are amenable to regeneration. The purpose of this paper is to focus attention on the recovery of nickel, cobalt, molybdenum, vanadium, and alumina from spent hydroprocessing catalysts by Gulf Chemical and Metallurgical Corporation and to review the use of sodium hydroxide and sodium carbonate for pressure leaching of spent catalysts.

Jan 1, 1986

By J. R. Montgomery, T. A. Phillips, F. Blackham, D. J. Adams

Underground water, whether it is a mine seep, in situ leach solu­tion, or a pollution plume, is difficult to track and monitor. Monitoring wells are costly to drill and may be placed in the wrong spot. This report describes a test of an electromagnetic technique to track acid water draining from the Midnite Mine near Spokane WA. The tests successfully mapped the path of acid mine drainage being collected at the mine from two seeps. Several small side branches flowing to smaller seeps and a mix­ing zone where relatively clean water mixed with the acidic water, were also mapped. The study has changed previous opin­ions on the flow of water through the site and will be used as a basis for future site remediation planning.

Jan 1, 1996

By D. C. McLean

One of the few innovations in hydrometallurgy in recent years has been the utilization of the chemistry of basic iron sulfates called jarosites. These have been used to make iron-zinc separations in the processing of zinc concentrates and are a very important factor in both the Duval and Cymet copper chloride processes as a means of preventing iron build-up in the closed leaching circuits. Copper oxychlorides are kindred compounds in that they are insoluble basic salts that form at low pH (1.5 to 3) and precipitate selectively from many base metal solutions. They have been reported in the chemical literature as far back as 1860, and a few of them are known in their mineralogical forms (particularly atacamite) usually as nuisance minerals because of their chloride content. Several patents describe their synthesis and use as fungicides and insecticides, and papers have discussed their formation as corrosion pro¬ducts on copper and brass piping (14).

Jan 1, 1979

The surface properties of eight coal samples were studied by measuring contact angles, coal oxidation, equilibrium moisture and film flotation. The penetration tests were carried out with do de cane, while dodecane and MIBC were utilized in batch flotation tests and in the simplified release analysis. Coal floatability results from the properties of coal organic matter and coal liberation. While the wetting of coal by water seems to be determined by the surface properties of coal organic matter, wetting by hydrocarbons correlates very well with the content of coal mineral matter.

Jan 1, 1992

By H. G. Kok

The concept of mobile crushers is not new. Since their introduction about twenty-five years ago, mobile crushers have continued to gain widespread attention. Mobile crushers reduce minerals in the open pit mine to sizes which can be transported by belt conveyors thereby reducing or eliminating the need for truck haulage. Truck haulage is costly, often representing as much as 50% of the total mining cost. More than 80% of the cost of truck haulage is for fuel and lubricants, tire replacements, and operators' wages, and it can be anticipated that the cost of these items will continue to increase at a steady pace. Compared to truck haulage, transportation by belt conveyor is more energy-efficient, less labor-intensive, and less subject to inflation. Therefore, mobile crushers, used in conjunction with belt conveyor systems, offer one of the most effective available methods of reducing energy consumption and mining costs,

Jan 1, 1980

By T. Kontos

Rogers Group, Inc., is the nation's largest privately held aggregates producer (primarily producing crushed limestone and secondarily sand & gravel) and a major regional asphalt paving construction contractor. The company also has interests in building supplies and coal. Facilities are concentrated in five states in the central U.S. (Ohio, Indiana, Kentucky, Tennessee, and Alabama), with an additional location in Southwestern Virginia. At the request of its then CEO and with support from the company's ownership, Rogers embarked on a strategic planning program in late 1986 by retaining an outside management consulting firm. The ultimate goal of this program was to develop a self-sustaining strategic planning process to inject a strategic dimension into every manager's business thinking and to improve company performance. Since then, Rogers has internalized the outside consultants' strategic planning framework --initially, using it wholesale, and later, greatly streamlining and tailoring both the planning process and product to meet the specific needs of the company. Implementation of strategies developed from strategic planning has resulted in significant improvements throughout the organization. The latest product of the strategic planning effort is a company-wide (or, "corporate") strategic plan that carries the theme of "Market Leadership through Excellence". This paper provides a case study of successful corporate strategic planning by examining the evolution of strategic planning at Rogers and by summarizing the key elements of a sound planning process and product.

Jan 1, 1994

A brief description of the mining method and ventilation system of the San Manuel Mine?s first presented; this is necessary to an understanding of the heat problem and cooling system. The problem of heat at San Manuel is discussed. Charts and graphs showing the relationships between ambient surface air and underground temperature conditions are given. A history of attempts to cool air at San Manuel is presented, starting with the first refrigeration type air coolers which were used in development headings, and followed by the underground water chillers that were used in conjunction with cooling coils. Goals for design of a centralized cooling system with ultimate heat rejection through surface cooling towers are presented. The problems found with using the centralized system in main cooling coils are discussed. Plans for modification of the centralized system as utilized is the summer of 1987 are given, along with results obtained and problems with the system. Plans for subsequent modifications are presented.

Jan 1, 1988

By W. D. Hausel

Archean supracrustal rocks of the South Pass greenstone belt of western Wyoming have been the State's most prolific source of gold and iron ore. Actual gold production statistics are incomplete, but as much as 400 to 500 thousand ounces may have been mined with some silver and tungsten as a by-product. Iron ore was also mined from the greenstone belt for 22 years, and production totaled more than 90 million tons. Immediately south of the exposed greenstone belt in the Oregon Buttes area, Tertiary boulder conglomerate, which has been eroded from the granite-greenstone terrain, may contain a gold resource of 28.5 million ounces (Love and others, 1978). The amount of gold placered from stream alluvium derived from these Tertiary conglomerates is unknown.

Jan 1, 1986

By C. E. Golson

Modern concrete technology emphasizes the basic qualities required of an acceptable aggregate: it must be clean, sound, homogeneous, and of a size gradation resulting in a concrete of the desired physical qualities at a minimum cost. In the case of coarse aggregates, crushing, scrubbing, and screening will usually provide the required material, although beneficiation is often necessary in order to eliminate unsound or deleterious fractions. Beneficiation is also applicable to fine aggregates,( but the processes most often employed are washing, classification, and dewatering.

Jan 1, 1959

By Rollien R. Wells

The Bureau of Mines was created in 1910 by an act of Congress and subsequently directed to: "...conduct inquiries and scientific and technologic investigations concerning mining, and the preparation, treatment, and utilization of mineral substances with a view to improving health conditions, and increasing safety, efficiency, economic development, and conserving resources through the prevention of waste ..." Under this broad charter, the Bureau's responsibilities have changed and grown from an almost exclusive concern with coal and coal mine safety to the present emphasis on a full spectrum of mineral producing and consuming problems. In the past 30 years, the domestic consumption of coal, oil, gas, metals, and industrial minerals has more than quadrupled, in parallel with the rapid and enormous growth in industrial production. Of the scores of metals and nonmetals essential to the Nation's progress and security, many are scarce and difficult to wrest from domestic sources. Reserves of some ores are dwindling. Available ore resources are becoming leaner and more difficult to treat. In recognition of this many faceted problem, the Bureau has engaged in a continuing quest for new and improved technology to enable economic exploitation of marginal minerals and fuels, to find substitutes for minerals in short supply, and to create better materials to meet the expanding and diverse requirements of the growing economy. The current central concern of the Bureau is focused on meeting projected fuel, metal, and mineral demands at the lowest real cost by recovery from available resources by new and improved technology that minimizes waste, hazards, and social and environmental problems.

Jan 1, 1970

By H. H. Richards, Ray L. Tobie, L. A. Thomas

GENERAL DESCRIPTION Since the beginning of operations, with the exception of a small tonnage mined by slushing, ore extraction has been by full gravity caving. Formerly, a checkerboard sequence of block undercutting was followed with the even-numbered blocks in one panel and the odd¬numbered blocks in the adjacent panel being mined. As these blocks were depleted, the intermediate or pillar blocks were mined (Fig. 1). Following this checker¬board, the mining sequence went through a number of changes, finally evolving into diagonal retreat panel cav¬ing by blocks (Fig. 2). The numbers in Fig. 2 indicate the sequence in which blocks were undercut. Gaps in the numbering sequence indicate undercutting on the level outside the illustrated area. Geology The ore body is a low-grade deposit of chalcopyrite mineralization disseminated throughout structurally weak, highly fractured, strongly altered granitic host rocks. It takes the shape of a gently dipping elliptical cylinder consisting of an ore shell of variable thickness surrounding an interior waste core. Major and minor axes of the mineralized cylinder are 1524 m (5000 ft) and 762 m (2500 ft), respectively, and length approximates 2438 m (8000 ft). Ore is sufficiently fractured to break readily into medium-coarse size. The igneous rock complex containing the ore body is covered by a wedge-shaped blanket of Tertiary con¬glomerate which was brought into place by faulting along the major regional structure of the San Manuel fault. Thickness of the conglomerate cap varies from only 9 m (30 ft) at the east end of the ore body to more than 610 m (2000 ft) at the west. Structurally, the con¬glomerate is much more competent than the igneous host rocks and, when caving, it breaks into massive chunks. Conglomerate boulders seen in drawpoints underground are very coarse. The total rock column over the initial mining area of the 1415 grizzly level was 354 m (1160 ft) of which 122 m (400 ft) was ore, 79 m (260 ft) was leached igneous capping, and 152 m (500 ft) was conglomerate above the San Manuel fault. Diamond Drilling: From 4572 to 7620 m (15,000 to 25,000 ft) are drilled annually from underground workings to delineate the ore body. MINE DEVELOPMENT Haulage Level In the south or main ore body (see Figs. 3-6), with the exception of the draw and transfer raises, all the extraction openings are concreted (Seaney and Tobie, 1965). The haulage panel drifts, which are 18 m (60 ft) below the grizzly drifts, are first driven with pre¬concrete ground support. The drift, which has an arched section, then is concreted using mobile collapsible steel tunnel forms. The haulage drifts leading from the pan¬els to the hoisting shafts are not concreted. After the panel drifts have been concreted, the raise stations from which transfer raises will be driven are constructed and the raise-station ore-drawing chute is installed. The chute is prefabricated of A-36 steel with undercut guillo¬tine gates made of abrasion-resistant 2.5-cm (1-in.) steel plate powered by 20-cm (8-in.) air cylinder installed on each side of the raise station. Transfer Raises The transfer raises are lined with 15 x 20-cm (6 x 8-in.) cribbing and are 1.22 m (4 ft) in the clear. Each cribbing is protected from wear by a high carbon steel angle which is nailed onto the cribbing. The transfer raises are driven from each side of the raise station on an angle of 1.1 rad (63°). Each raise con¬sists of a main and a backover branch. The transfer¬raise driving crew consists of two men working one shift only. Grizzly Drifts After the transfer raise reaches the grizzly level, the grizzly drift can be driven. The grizzly drifts are spaced at 10.6-m (35-ft) centers and are driven parallel to the long axis of the ore body (see Fig. 2). This drift is driven by a two-man crew working on one or more drifts at a time using feed-leg machines. The eight grizzlies in the 42.7-m (140-ft) long drift are spaced at 5.3-m

Jan 1, 1982