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By W. T. Benson

Peacetime production of mercury in the United States is controlled by world mercury prices, with significant lags to be expected between price increases or decreases and resultant increased or decreased production. Twenty-four mercury-bearing mines and prospects in widely separated districts in western and central Nevada and one property on the Nevada-Oregon border were examined and sampled. The purpose of the project was to determine if some of the properties warranted more extensive exploration work to obtain information on possible reserves of commercial-and sub-commercial-grade ores. The investigation of mercury deposits in Nevada was sufficiently widespread and indicated several areas of interest in the State that merit further exploration work.

Jan 1, 1956

By M. O. Serbousek

The load-transfer mechanics of fully grouted roof bolts in coal mines have been investigated in laboratory and analytical studies. The purpose of this Bureau of Mines research is to increase understanding and better interpret data from routine field pull tests and to develop a numerical model of a grouted bolt that can be used in a global computer model of a mine roof. Analytical studies using closed-form solutions and finite-element techniques were compared to experimental results. Laboratory work includes variation of bolt length, hole diameter, and grouL type. Pull tests were pel'fol·med on 4-, 2-, and I-ft bolts in holes of 1-and I-3IB-in diameters. Both polyester resin and inorganic grouts were used as the anchorage medium. Strain gauges were installed on the bolts at several locations to observe the rate of load transfer from the bolt through the grout to the rock mass when a force was applied at the bolt end using standard jack pull testing procedures and equipment. The average anchorage length of 4-and 2-ft bolts was 22 in. Grout type and hole size variations did not produce a significant effect on the rate of load transfer from the bolt to the rock.

Jan 1, 1987

By W. F. Watts

The U.S. Bureau of Mines has conducted research on methods to reduce and to measure diesel particulate matter (DPM) aerosols in underground coal mines. One objective of this report is to present findings from an investigation of the DPM reductions obtained by an engine-mounted integrated control system consisting of a dry system (DS) and a diesel particulate filter (DPF). Another objective is to present results from the usc of a size selective personal sampler to measure DPM concentrations in an underground coal mine. Bureau laboratory tests of the integrated dry system and diesel particulate filter (DS-DPF) have shown that DPM emissions can be reduced up to 97 pet with little change in gaseous emission concentrations. The DS-DPF is undergoing certification tests conducted by the Mine Safety and Health Administration (MSHA). Subsequent to passing all safety requirements, it will be tested in an underground coal mine. A baseline survey of DPM concentrations and aerosol size distributions in a cooperating mine was completed in August 1988. A prototype DPM personal sampler was tested during this survey. Based on results from this test, an improved unit has been developed. This unit is scheduled for extensive field testing by MSHA in 1989.

Jan 1, 1989

By George H. Holmes

This paper is one of a series on mining methods and practices published by the Bureau of Mines. It describes quarrying methods and crushing practices of the U. S. Lime. Products Corp. at its Sloan and Apex quarries. Calcining and milling processes. at the Sloan and Henderson plants also are outlined. The Sloan dolomite and limestone quarries and plant are in secs. 12 and 13, T. 23 5., R. 60 E., and sec. 18, T. 23 S., R. 61 E., M.D.B. &M., Clark County, Nev., about. 17 miles by paved highway southwest of Las Vegas (fig. 1). The Apox limestone quarry, and crushing plant are in sec. 26, T. 18 S., R. 63 E., M.D.B.&M., Clark County, Nov., approximately 18 milos northeast of Las Vegas, adjacent to U. S. Highway 91 (fig. 1). The Henderson calcining plant is Inc., in sec. 13, T. 22 S., R. 62 E., 14 miles southeast of Las Vegas on U. in a reduction unit of Basic Magnesium, M.D.B. &M., Clark County, Nev., about S. Highway 93 (fig. 1).

Sep 1, 1949

By D. Harrington

In this period of generally increasing taxes of various kinds, one hears less complaint by mining companies about the high cost of workmen's accident compensation than was the case a few years ago, the reason perhaps being that other and more pressing phases of the tax problem now over shadow the heavy expenditures for compensation premiums which a few years ago were considered a severe burden on the mining industry. Nevertheless, the financial expenditures of the mining industry in higher compensation benefits and hospitalization or in higher premium rates, or both, instead of being less have actually increased in many States in the past year. In the spring of 1937, proposals for increased benefits to injured employees in compensation, hospitalization, or medical aid were actively before legislatures in California, Connecticut, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Massachusetts, Michigan, Minnesota, New Mexico, Oregon, Pennsylvania, South Carolina, Texas, Utah, Washington, Wyoming, and possibly other States. In some cases, the proposed increases in benefits were so much greater than expenditures for similar items in the past that premium rates per $100 of payroll would almost certainly rise sharply. At this same time, occupational-disease-compensation coverage also was under consideration by legislatures in Arkansas, California, Delaware, Idaho, Indiana, Kansas, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Jersey, Ohio, Pennsylvania, Tennessee, Utah, and Washington. Sooner or later (and probably within the next few years) occupational-disease compensation will be accorded practically as wide recognition as accident compensation receives at present, and, unquestionably, mining in all of its branches will be affected more or less drastically. Hence, the present outlook is that the mining industry, in company with practically all other industrial activities, will be confronted by materially higher compensation costs than those of the past or the present, to which rather violent exception has been taken, at least in some States and at some times.

Jan 1, 1938

By George S. Rice, F. B. LANEY, A. J. Lanza, Edwin Higgins

Under its organic act the Federal Bureau of Mines is directed to conduct investigations relating to the improvement of health conditions in the mineral industries. This report describes the lead and zino deposits and the mining methods employed in the sheet-ground area of the Joplin district, Missouri, and discusses the causes and the methods of abating rock dust in the mines, the chemical and physical characteristics of the dust, and the quantities present in mine air. Although the preliminary investigation included a number of the "soft-ground" mines, the writer spent the larger part of his time in the sheet-ground mines, for in them alone was siliceous dust found in appreciable quantities. Some results of the preliminary investigation have been published by the Bureau of Mines in Technical Paper 105.a The territory covered in t~lCpreliminary investigation, during the period between November 7 and December 6, 1914, embraced parts of Jasper, Lawrence, Newton, and Greene Counties, Mo., and outlying districts in Kansas and Oklahoma. The remainder of the field work, to which 84 days during the period from February 9 to July 19, 1915, were devoted, was confined to the sheet-ground mines, the most important of which are situated in the vicinity of Joplin, Webb City, Carterville, and other smaller near-by towns in Jasper County, Mo.

Jan 1, 1917

By Lloyd L. Farnham

This paper is one of a series describing the mineral resources of the Nation, including location, history, production, ownership, geologic setting, and mining methods for most of the known manganese deposits in New Mexico, With few exceptions these descriptions are the result of field examinations by the writer. Of 32 counties, the 12 which occupy the western half of the State contain all the known manganese deposits, These counties are Catron, Dona Ana, Grant, Hidalgo, Luna, Rio Arriba, Sandoval, Santa Fe, Sierra, Socorro, San Juan, and Taos. (See fig. 1.)

Jan 1, 1961

By Bernard Lewis

During the past 10 years the technical investigations conducted by the Explosives Division of the Mine and Explosives Bureau of the Bureau of Mines have been described in a series of summarizing reports prepared by Wilbur I. Huff, consulting explosives chemist of the Bureau. These reports covered the…

Dec 1, 1947

Commodities statistics and other information are available through the following three systems: Internet Access: To access the USBM Gopher server on Internet, connect to: gopher.usbm.gov port 70, using gopher client software. Or contact the Systems Administrator for technical questions: Matt Klevemann, 412-892-6499 (klevemmc@miner.usbm.gov) These USBM materials are available on Internet, with more to come in the future: Publications and other research findings, including this bimonthly publications list, newsletters, tech transfer updates, environmental technology research, health and safety information. USBM software products Media materials and speeches. Mines Data: Computer bulletin board. Log on via modem through 202/501-0373, or call 202/501-0406 for technical assistance. Mines FaxBack Return fax service. 1. Use the touch-tone handset attached to your fax machine's telephone jack. (ISDN [digital] telephones cannot be used with fax machines.) 2. Dial 202/219-3644. 3. Listen to the menu options and punch in the number of your selection, using the touch-tone telephone. 4. After completing your selection, press the start button on your fax machine.

Jan 1, 1995

By Donald W. Mitchell

Certification tests for urethane-foam systems and techniques for apply-ing foam safely in mines are described. Fire hazard from foam exists if flame propagates beyond the ignition source or penetrates the foam. Foam that passes the certification tests can be applied on stoppings, continuous sections of ribs of relatively wide passageways (with no foam on the roof), short sections of roof such as overcasts, roof cavities, and intersections (with no foam on the ribs), and between buntons on one wall of a shaft. Foam on the ribs and adjoining roof presents a fire hazard. Stoppings covered with foam passing the certification tests are resistant to penetration of heat, flame, and smoke than similar stopping without foam. Flame propagation can be arrested by water sprays. Spontaneous ignition of foam can be prevented.

Jan 1, 1966

By Paul T. Allsman

The Salt River range vanadium deposits are situated 3 to 6 miles east and southeast of Afton, Lincoln County, Wyo. The vanadium occurs in a continuous bedded shale zone of the Phosphoria formation extending from the vicinity of Afton into southeastern Idaho. The Bureau of Mines explored several of these vanadiferous-shale deposits between December 1942 and December 1943 and conducted metallurgical tests on the ores. The areas investigated were west Swift Creek, the Dry Creek, and the Cottonwood Creek. The vanadiferous-shale beds have been folded sharply into a series of tightly compressed, eroded anticlines and synclines, which form the Salt River range. The vanadium occurs in a series of narrow shale or mudstone beds contained within the phosphatic-shale member of the Phosphoria formation. Exploration by the Bureau of Mines consisted of surface trenching and underground work over 18 miles of outcrop of vanadiferous shale with an average assay value of 0.866 percent V2O5.

Jan 1, 1949

This report provides concepts for two automated longwall mining systems; one for operation in a 42 to 57-inch thick section of the Lower Kittanning coal seam, the other in a 57 to 72-inch thick section of the Pittsburgh seam. The Lower Kittanning concept uses a single-drum bidirectional shearer and 500-ton capacity 4-leg chocks and the Pittsburgh concept uses a double-drum shearer with 500-ton shields. Each concept is designed to produce in excess of 2,500 tons of clean coal per shift with a 6-man face crew. The automated longwalls consist of off-the-shelf control system hardware attached to standard longwall equipment. Control hardware includes a control and display console; prime and backup mini-computers; multiplex data transmission, power, and control lines; several remote terminals which serve as interface junctions; and various sensors and actuators located on the longwall equipment. The system can be operated either fully automatically, remotely or manually.

Jan 1, 1976

By Andrew Allan

During recent years underground production for the Pennsylvania anthracite region has reached the lowest output per man per day figure of the last decade and a half. This fact, combined with increased unit costs for labor and material, has forced the market price of anthracite ever higher. Over the years the mines have become deeper, and haulage distances have increased, thus adding to the mining costs. The industry now recognizes the need for new mining techniques to offset increasing costs. The Federal Bureau of Mines, through its Anthracite Research Laboratory, is engaged in a program of underground-mining research in cooperation with anthracite-producing companies to aid in reestablishing the economy of the region by introducing methods and/ or machines that will reduce underground-mining costs and, at the same time, enhance the safety of the workmen.

Jan 1, 1953

By R. D. Leitch

[The accepted theory of acid formation in coal mines with the subsequent appearance of the acid in coal-mine drainage, is oxidation of iron pyrite and subsequent solution and hydrolysis of the iron sulphate formed. It has also been found that 5 gobbed sections and worked-out areas, where there is usually an abundance of iron pyrite-bearing, materials in contact with air, are the sections that make the most important contribution to the quantity of acid drainage. It would thus seem obvious that if oxygen can be kept out of contact with tae acid-forming materials in tie- sections mentioned the amount of acid in coal-mine drainage could be reduced markedly and corrosion problems with mine pumping equipment and general stream pollution mitigated thereby. Although the efficiency of the suggested remedy as been borne out by laboratory experiments6, it has appeared desirable to substantiate the laboratory work by field observations in so far as pertinent data are available. It has been difficult to learn of mines or sections of mines about to be sealed, whereby an actual comparison of the drainage before and after sealing can be made. In view of that difficulty it has been necessary to devote attention to a comparison of the character of the water from areas already sealed with that from open but otherwise comparable sections of the sane mine. Previous cork has shown that the acidity of drainage in different parts of the same mine may vary, but if it can be shown also that the water from sealed areas is with but fen exceptions less acid than the otherwise similar open sections of tae same mine, the laboratory finding will be supported in a practical gray. This report presents some of the evidence that has been obtained.]

Jan 1, 1930

By J. D. Dixon

This Bureau of Mines report describes the results of an investigation for developing and applying procedures for stabilizing excavations openings in highly yielding ground. The approach developed in this report involves nonlinear modeling of the progressive relaxation of the zones of rock mass around the excavations opening where Coulomb criterion of failure is exceeded. Stresses are calculated by using a computer code; Coulomb-failure condition is examined for both intact rock and joints (using strength parameters [~] and c). The rock mass in the failed zones is relaxed by reducing the Young's modulus of the rock based on an empirical formulation that is a function of the shape of the opening and the extent of the failed zone. In addition, the material in the failed zone is assigned reduced strength paramters 0' and c'. The limiting (or convergent) relaxed zone is obtained through an iterative process by manually changing the rock modulus and the strength parameters between iterations. Support pressures are computed by applying forces normal to the excavation surface. The approach is applied to the analysis of stability and support requirements for an entry in a longwall coal mine.

Jan 1, 1985

By Thomas Brunsing

The program was carried out to develop deep kerfing and core breaking techniques to be incorporated into the design of a field prototype hard rock mining machine. The field machine is designed to mine non-abrasive bedded deposits up to 20,000 psi in uniaxial compressive strength. The mining technique involves cutting approximately 2 ft deep parallel kerfs spaced 2 ft apart in either a horizontal or vertical direction and subsequently breaking out the cores so defined. The prototype machine is intended for demonstration of the technique in a quarry or equivalent field environment. The program was aimed at minimizing the required kerf width, obtaining reliable breaking within that kerf width and determining cutter blade requirements necessary to achieve a mining rate of 20 ft3/min. Full scale breaking experiments and 1/2 scale kerfing experiments were employed to evaluate the system. High strength concrete test specimens were used to simulate the rock being cut and broken. The test results indicate the kerf/break technique can achieve the desired mining rate by utilizing two 7 ft diam blades to cut 2 in. wide by 24 in. deep kerfs. A lateral load applied at the base of the kerf (base shear) was selected at the core breaking technique to be employed by the full-scale prototype machine.

Jan 1, 1983

By J. S. Webb

This is one of a series of papers dealing with mining methods, practice, and costs be¬ing published by the United States Bureau of Mires. In this paper a description of the mining practice in vogue at the Braden unit of the Kennecott Copper Corporation is undertaken. PRODUCTION At present (1931) the entire production of ore is being obtained from the Teniente mine. The miring method in use is an adaptation of block undercutting which has been a development of the stoping and pillar caving experience obtained at this property. Improvements in mining practice are constantly being made.

Jan 1, 1932

By Chas. F. Jackson

The annual reports of the supervising engineers of the nine sections comprising the Mining Division are assembled here and constitute the annual report of the division. In planning activities the aim is to adapt them to changes in conditions, in the needs of the mining industries, and in the public interest; those that contribute most to solving the present problems are emphasized, investigations of less immediate importance being recessed if necessary. The strategic minerals investigations of the bureau afford an example of this change in emphasis to problems of immediate and urgent interest, and during 1941 they comprised, upon the basis of appropriations and expenditures, more than 90 percent of the work of the division.

Jan 1, 1941

By A. Oyler

The U.S. Bureau of Mines has compiled data on the major causes of fatal and nonfatal electrical accidents related to mining, and their associated costs, for the 1980-85 period. Specific electrical problem areas were identified, allowing future research to be focused on reducing the frequency of these occurrences. Recommendations for reducing the number of electrical accidents and injuries are provided. The four mining sectors for which data were gathered and compiled are (1) underground coal mines, (2) surface at underground coal mines, (3) underground metal-nonmetal mines, and (4) surface at underground metal-nonmetal mines. Nine categories of information pertaining to specific aspects of the accident are used in this report: activity engaged in when the accident occurred, source of injury, job title, mining method, location, machine, nature of injury, accident type, and part of body affected. The number of years of experience at the specific job the employee was performing when the accident occurred, time of accident, and in the case of nonfatal accidents, the total days lost per year, are also summarized.

Jan 1, 1990

By L. G. Marshall

This report presents a cross section of the sand and gravel operations in the Minneapolis-St. Paul area. The study covers individual operations, economic problems peculiar to the industry, glacial geology of the area and its effect upon the grades and types of products, and past, present, and future trends of the expanding population and its effect upon the industry.

Jan 1, 1963