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By E. Z. Casassa

There has been a recent revival of interest in concentrated coal/water slurries as a substi¬tute for fuel oil or for coal/oil mixtures, particularly in electric power generation. The idea is not a new one. Coal/water slurries were transported by pipeline in the U.S. in the early nineteen-sixties, and the Black Mesa coal pipeline has been in operation for several years, while in Germany, coal/water slurries were being burnt for power generation in the early nineteen-seventies, as described by Merten and Höner (1972). Since coal is not a pure substance but a carbonaceous mixture, the different chemical and physical behavior of coal/water dispersions from different deposits must be understood in order to optimize the properties of the result¬ing slurry fuels. Since minerals which are minor constituents of coal may also strongly affect slurry properties, coal chemistry may vary considerably even within a single deposit. Thus it is unlikely that there will be a single formula for optimizing the slurry properties of all coals, and even the answer for coal from a single source may change with time.

Jan 1, 1983

By Tapiwa Chenje, Victor Olivas, Peter Radziszewski

"Ore breakage and grinding media wear have always been considered and determined separately in laboratory tests. However the two processes are linked with the ore broken down in any comminution device being responsible for the majority of the steel wear experienced. The Comminution Dynamics Laboratory (CDLab) successfully developed a test methodology that can more accurately predict grinding media wear in tumbling mills than the Bond Abrasion test. This paper looks at the possible application of the abrasive wear methodology to determine breakage parameters of the same ore used in the abrasion test. Results indicate that breakage parameters comparable to t10 can be determined using the Steel Wheel Abrasion Test (SWAT), while using significantly less ore than standard breakage tests.BACKGROUNDThe Rubber Wheel Abrasion Test (RWAT) is an internationally accepted and widely used method for determining the abrasion wear behavior of materials. The abrasion wheel test was developed to primarily utilize a steel wheel (Brinell, 1921). Haworth (1949) criticized using of the steel wheel by arguing that increasing the contact area size in the steel wheel test causes a change in the wear rate with time. He suggested that the use of a rubber wheel instead eliminates this problem, leading to the adoption of the RWAT which was standardized in ASTM G65 (2004).Radziszewski (2002), however, found that the use of the Steel Wheel Abrasion Test (SWAT) was more applicable for wear testing in the mining industry for two critical reasons. Firstly, the major cause of wear in a ball mill, the most frequently used comminution device, is ball-ore-ball contact and also ball-ore-liner which both are metal-ore-metal contact. Therefore, using the steel wheel has the advantage of providing a similar abrasive environment to the one that takes place in a real ball mill. Secondly, the SWAT creates the potential of running experiments at much higher force regimes that are closer to what happens in actual mills, unlike the RWAT which is a low stress test."

Jan 1, 2011

By Rodolfo Espinosa

"Industrias Peñoles, S.A. de C.V. in Mexico, has nine mining operations, six managed by Peñoles (base metal mines) and three managed by Fresnillo plc (precious metal mines). Seven of the operations use flotation and the other two are heap leach operations, one for gold and the other one for copper.This paper gives a brief introduction of Peñoles, shows mine locations and describes the main process characteristics of each concentrator. It also presents four of the new operating practices that were implemented over the last four years to improve the economics of the mining operations. These include (1) the use of centrifugal gravity concentrators to increase the recovery of gravity recoverable gold (GRG) and silver (GRS), (2) the use of expert systems to reduce process variability while increasing grades and recoveries, (3) the application of the Six Sigma methodology to key projects to ensure success and personnel development and (4) the use of water chemistry fundamentals to identify chemistry problems and design adequate solutions for improving grades and recoveries.INTRODUCTIONPeñoles was founded in 1887. It is a mining group with integrated smelting, refining and chemicals producing operations. Peñoles is the world largest producer of refined silver and metallic bismuth, the leading Latin American producer of refined gold and lead. It is amongst the world leading producers of refined zinc and sodium sulfate.Peñoles operates and controls six underground mines in Mexico and is the largest producer of zinc and lead of the country. It also produces copper concentrates and cathodes. Through its 77.1% equity stake in Fresnillo plc (a London Stock Exchange listed company); Peñoles is also a significant producer of gold and silver. Fresnillo plc operates three precious metal mines in Mexico. While Fresnillo is the world largest primary silver mine, Ciénega and Herradura are two leading gold mines of Mexico. Figure 1 shows a map of Mexico indicating the locations of the Peñoles mines. The main process characteristics of each concentrator are listed in Table 1."

Jan 1, 2011

By D. V. Gaffney

This report presents the results of a three-phase investigation of the feasibility of using cemented coal waste in active underground coal mines to prevent mine subsidence. Coal caste was broadly defines to include waste from both coal preparation plants and coal-fired power plants. Underground systems with potential for cemented backfill are determined through identification of current mining methods and available technologies for cemented backfilling and consideration of materials and systems constraints upon mining and backfilling integration technical concerns including operation, health and safety, materials utilization, environmental impact, applicability and techni¬cal status are assessed for six (6) systems which were identified as potentially feasible. Two (2) of these systems are conceptualized in a hypothetical case history and developed to further assess their operational and economic feasibility. Comparisons of costs among both systems and with costs of surface disposal are presented. Also presented are the conclusions reached concerning the present feasibility of using cemented backfill in active coal mines and potential avenues for further research. Appendices contain further consideration for design of cemented mixtures to be used in backfilling, the results of laboratory testing of mixtures rich varying concentrations c: waste products and cementing agents, and an annealed bibliography

Jan 1, 1981

By C. M. Harrer

Reconnaissance investigations were made of 129 iron occurrences in Arizona to determine their extent, attitude, and potential; character samples were analyzed to determine their quality and impurities; and pioneer metallurgical investigations were made on character samples to present their metallurgical problems. Some factors influencing past and potential western iron markets are discussed. The location, features, qualities, extent, and potential of iron occurrences and some associative resources--limestone and dolomite, coal, petroleum and natural gas, power, and water are discussed. The most abundant iron minerals are magnetite and hematite. The higher grade deposits are extensive contact-metamorphic or pyrometasomatic replacements of calcareous Paleozoic to Proterozoic rocks associated with intrusives. Large low-grade deposits of great potential are present as Precambrian taconite, semitaconite-, and jaspilite-like iron formations of magnetite-hematite. Iron occurs also as low-grade concentrations of magnetite in extensive alluvial deposits. Nonferrous metallurgical slags, nearly 100 million tons, are considered a potential source of iron. Various accessory elements are associated with the iron minerals and these pose metallurgical and economic problems.

Jan 1, 1964

By C. M. Harrer

Reconnaissance investigations were made of 129 iron occurrences in Arizona to determine their extent, attitude, and potential; character samples were analyzed to determine their quality and impurities; and pioneer metallurgical investigations were made on character samples to present their metallurgical problems. Some factors influencing past and potential western iron markets are discussed. The location, features, qualities, extent, and potential of iron occurrences and some associative resources--limestone and dolomite, coal, petroleum and natural gas, power, and water are discussed. The most abundant iron minerals are magnetite and hematite. The higher grade deposits are extensive contact-metamorphic or pyrometasomatic replacements of calcareous Paleozoic to Proterozoic rocks associated with intrusives. Large low-grade deposits of great potential are present as Precambrian taconite, semitaconite-, and jaspilite-like iron formations of magnetite-hematite. Iron occurs also as low-grade concentrations of magnetite in extensive alluvial deposits. Nonferrous metallurgical slags, nearly 100 million tons, are considered a potential source of iron. Various accessory elements are associated with the iron minerals and these pose metallurgical and economic problems.

Jan 1, 1964

By Jr. Boyle

This report analyzes the availability of chromium in the form of ferroalloy products (high-carbon and low-carbon ferrochromium and ferrochromium-silicon) and chromite products (metallurgical, chemical, refractory, and foundry sands) in market economy countries (MEC's). A total of 873.5 Mmt of in situ material, containing 202.5 Mmt of chromium, in 10 MEC countries was analyzed for availability as of the January 1989 study date. Extraction and beneficiation of this in situ material would result in 475.4 Mmt of marketable chromite products. As analyzed, 288.5 Mmt of these chromite products would be available for export or for internal chemical and refractory use and 186.9 Mmt would be smelted in-country to produce 74.3 Mmt of high-carbon ferrochromium, 3.9 Mmt of low-carbon ferrochromium, and 2.0 Mmt of ferrochromium-silicon, all available for export. A network flow model, which includes centrally planned economy countries (CPEC's), was also constructed to analyze world chromium supply and demand interactions for the period 1986 through 1994 and to address a hypothetical North American embargo on direct imports of all South African chromium products beginning in mid-1990. The model shows capacity constraints developing in the MEC high-carbon ferro chromium industry in 1987 and a possible subsequent overreaction by the industry in terms of new capacity additions. The results suggest that sufficient chromium is available to North America should an embargo on direct imports from South Africa be imposed by its governments. However, the effect on export revenues in South Africa is relatively small, and timely increases to world ferrochromium, chemical chromite, and foundry sand chromite capacities would be required.

Jan 1, 1993

A compilation of papers presented at The Second WVU Conference on Coal Mine E1ectrotechnology in Morgantown, West Virginia on June 12 -14, 1974. Papers cover areas of electric power, electronic communications, detection and location of trapped miners, and electronic sensors and monitoring systems.

Jan 1, 1974

By Michael Radnor

The purpose of the study was to 1) examine the social and economic impacts of surface mine blasting in relation to variations in conditions of terrain and geology, population density and type, levels of ground motion and air blast; 2) consider technical, legal and government policy issues; and 3) examine the potential, nature and extent of surface mine blasting impacts and its regulations upon both communities and surface mining companies. Phase One designed the empirical research and technical analyses of Phase Two, focused upon surface coal mining and quarrying in the Eastern U.S. Several broad conclusions are evident: 1) blasting is not the major issue for communities or surface mine companies; 2) while the number of instances of severe cracking or annoyance are relatively small, the impact can be severe for individuals immediately involved; 3) blasting/drilling cost curves tend to rise significantly at intervals below 1.0 particle velocity, in/sec, dependent upon the size of a permit area and the size of a mine; and 4) the legal, complaint, cost and density analyses do not suggest the need for a general lowering of present regulations.

Jan 1, 1981

By Lyman Moore

This Bureau of Mines report describes 2nd evaluates iron ore resources in California and Nevada and analyzes the California and Japanese iron ore markets in which these resources will be used. The competitive position of California-Nevada ores, in these markets, was estimated by comparing regional iron ore prices, production costs, and transportation costs with those of foreign suppliers. Resources were determined to be sufficient to produce the equivalent of 585 million tons of 64-percent iron pellets at a price of less than $15 per ton delivered at California ports. Much higher tonnage could be produced at higher prices. Iron ore requirement of the California iron and steel industry will increase to an estimated 15.9 million tons by the year 2000. A study of the iron ore production potential of California-Nevada deposits and of out-of- State sources indicated that this ore requirement can be supplied most economically by California-Nevada ores. Iron ore import requirements of the Japanese iron and steel industry will increase to an estimated 150.0 million tons by the year 2000. A study of price trends in this market indicated that very little California-Nevada iron ore will be sold in Japan after 1973 when existing sales contracts expire. Iron ore-exports might be economically possible if ore could be transported from California to Japan at ballast rates as backhaul on existing petroleum shipping.

Jan 1, 1971

By WL Wagner

This report presents a quality control approach to the derivation of strategies for monitoring a work environment; specifically, the environment in underground mines where diesel-powered equipment and blasting agents are used. The approach is presented as a series of 22 steps called the Monitoring Strategy Development Scheme. The scheme is an orderly method for selecting from a number of options a strategy or tactics to cost effectively meet the requirements of a chosen objective related to the monitoring of breathing zone air quality. The scheme provides a format to quantify many of the factors that influence the selection of on strategy or tactic over another, and to ensure that important considerations are not neglected. The premise that breathing zone air in work environment can be considered to be manufactured product and that, therefore, conventional quality control approaches are applicable, is introduced. Typical approaches to the quality control of manufactured products and how these approaches can be applied to the selection of monitoring strategies are discussed.

Jan 1, 1983

By Wm. O. Vanderburg

This report on the mining and milling of tungsten ores is the second part of a general study of the domestic tungsten industry. The first part, comprising general information on tungsten, has been printed as Bureau of Mines Information Circular 6821. The purpose of these papers is to increase efficiency in the mining, preparation, and utilization of the tungsten resources of the United States. The tungsten industry forms so small a part of the vast mining and metallurgical operations of the illation that private metallurgists have not had enough inducement to give special attention to the recovery of tungsten minerals from the ores, and many of the small companies are financially unable to undertake research work. A study of the milling of tungsten ores reveals that further improvement is possible, especially in the treatment of slimes. Recent experimental work by the Bureau shows that the flotation process is applicable to certain tungsten ores. The future of the tungsten industry it the United States depends to a great extent on utilization of the low-grade deposits of the contact-metamorphic type.

Jan 1, 1935

By W. A. Grosh

Records show that much of the lead produced in the Upper Mississippi Valley lead-zinc field was taken from natural openings along crevice systems at shallow horizons or at the surface. During the early history of the district, the shallow deposits were worked intensively; but in recent years the production of lead, except as a byproduct of deeper mining for zinc ores, has not been significant. Considering the methods of early mining, the character of mineralization, and the fact that galena can still be found on the surface of the old digging areas, it was reasoned that enough mineralization might remain on and above bedrock to permit, through the use of modern equipment and methods, economical re-treatment of surface material in the digging areas.

Jan 1, 1960

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 Otto Ruhl

The zinc-lead ore reserves of the Tri-State district of Kansas, Missouri, and Oklahoma, as of December 31, 1947, are estimated at a total of 66,100,000 tons of crude ore containing 2.18 percent metallic zinc and 0.38 percent metallic lead. The Bureau of Mines began estimating the reserves in October 1945 and completed the' work December 31, 1947. A total of 38,900 acres of land representing approximately 5 percent of the area of the district is covered in this report. The work was confined for the most part to properties developed or partly developed by drilling and underground workings, and to acreage sufficiently drilled out to indicate ore of enough tonnage to make a commercial undertaking. The acreage in which ore reserves exist is widely distributed in all three States. A map of the Tri-State area is shown in figure 1. The remaining 95 percent of the area is not necessarily nonproductive but represents, possibilities for future exploration and development of additional mineral resources when and if economic conditions or national necessity encourage such work. Of the total reserves, 41 percent are in Missouri, 38 percent in Kansas, and 21 percent in Oklahoma.

Jan 1, 1949

By T. W. Quayle

This paper describing mining practices at the United Verde copper mine, Jerome, Ariz., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts f the United States. At present mining operations are being conducted both underground and by electric shovels in an open pit. The open-pit work has been described by E. M. J. Alenius in a previous publication of the Bureau of Minos;3 the present paper will be confined to a description of the underground mine. The underground methods comprise horizontal cut-and-fill, shrinkage with delayed filling, horizontal square-set, inclined square-set, and top slice. The normal daily production of the underground mine is 3,000 tons of copper ore per day, requiring the employment of 900 men underground.

Jan 1, 1931

By Andrew P. Gize

The analytical approaches used to solve a specific problem are dependent upon the information required, coupled with limitations imposed by available facilities, costs, and time. The organic matter associated with ore deposits has the potential to yield information for two problems. Information can be obtained to provide guidelines for prospecting, and, secondly, to solve genetic problems. A major potential of organic matter in providing prospecting guides lies in the high thermal sensitivity of organic matter in sediments which are metamorphosed at grades lower than greenschist facies. The organic matter can then be used to map thermal anomalies potentially associated with mineralization. The analytical approach is to determine the thermal maturity of the total organic matter, or of specific fractions, using techniques which are relatively quick and inexpensive. Consideration of genetic models (for example, reduction, complexing, involvement of oil field brines) generally requires more specific information than the overall thermal maturity of the organic matter, necessitating infor¬mation on molecular composition and structure. The facilities, time, and cost of this information are greater than for mapping thermal anomalies. The analytical techniques discussed include elemental analyses, spectroscopy (infra-red, visible and ultra-violet), Fourier Transform infra-red, nuclear magnetic resonance, extraction, pyrolysis techniques, chromatography and mass spectrometry.

Jan 1, 2013

By C. H. Riggs

This report of a petroleum-engineering study of the Flat Rock oil field, Osage County, Okla., describes the geology, reviews the production history, and estimates remaining oil reserves. The Flat Rock field in the southeastern corner of Osage County approximately 6 miles northwest of Tulsa. Okla., was discovered in November 1904. The field was one of the first of many Bartlesville-sand fields developed in eastern Osage County during the early part of the 20th century. Although substantial oil reserves remain in the pressure depleted sands in some parts of the field, their economic recovery by water flooding will require careful consideration of the many factors involved.

Jan 1, 1954

By Russell R. McLellan

Under the Heavy Metals Program, investigations were conducted at the old Badger dill placer mini in Nevada County California to collect data and information regarding drilling and sampling methods and deposit characteristics. The studies contributed to a team effort by five Bureau of Mines research groups to develop new or improved placer mining technology in the Tertiary gold-bearing channel gravel of northern California. This report describes the techniques used and the results obtained in the sampling and drilling stage of deposit delineation studies that were conducted by the Denver Mine Systems Engineering Group. Sampling included the collection and processing of 400 tons of largo and small volume samples from drill holes, underground workings, surface pits, and blast hole rounds. A total of 355 samples averaging 2,296 pounds per sample provided reasonably accurate data for analysis of the gold distribution. These studies indicate that the bulk of the gold is within 40 foot of bedrock in stacked, lenticular zones of cemented gravel that are largely confined to the relatively narrow, meandering course of the deepest portion of the bedrock channel. Drilling studies involved the testing of three types of truck-mounted drills including rotary, bucket and vibratory, none of which proved to be a completely versatile tool for sampling quickly and reliably both consolidated and unconsolidated gravel.

Jan 1, 2012

By J. R. Thoenen

This paper outlines briefly results of seismic measurements recorded in the vicinity of quarry blasting under practical operating conditions. The data cover field work done from January to the middle of August 1930, during which time records were made of 61 blasts in 19 quarries. Of the tests made, one was in biotite-gneiss, two in dolomite, two in a flintlike volcanic complex, three in gabbrodiorite, five in trap rock, and six in limestone. One quarry was in Alabama, two were in South Carolina, two in New York, four in Kentucky, five in Connecticut, and five in Massachusetts. Explosive charges ranged from 0.30 pound to 41,900 pounds, and the method of shooting varied from mud caps through hammer and wagon drill holes to churn drill holes and coyote tunnel shots.

Jan 1, 1937