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In 2004, a total of 741 nonmetal mining operations reported employment to the Mine Safety and Health Administration (MSHA). These mines (e.g., potash, gypsum, salt) comprised 5.1% of all operations.

Sep 1, 2007

By Khamis Y. Haramy

This Bureau of Mines paper describes the use of the borehole shear tester (BST) In mines. Assembly and procedure sections explain how the equipment is assembled and used properly. Schematics of the BST, limitations, test hole specifications, data recording and calculations are all explained briefly, and an example of the data collecting and calculations is given to assist understanding.

Jan 1, 1981

By J. Douglas Causey

In 1988, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied part of the 12,740-acre Blue Canyon Wilderness Study Area (OR-003-073) in order to evaluate its identified mineral resources. The study area is in Malheur County, OR, about 27 miles northwest of Jordan Valley. The study area is underlain by Tertiary welded tuff, tuff, perlite and tuffaceous sedimentary rocks capped by basalt. Jasper has been mined from several localities. Some mining has been done by hobbyists. However, the area has been covered by mining claims since 1964, with mining done by commercial operators. This region has been a source of "Owyhee picture" and other similar jaspers. More recent exploration has focused on the gold potential of nearby areas such as Quartz Mountain and Red Butte.

Jan 1, 1989

To allow the controlled yielding of mine walls in order to reduce rock-burst hazards and reduce maintenance caused by excessive squeezing forces. Approach Rock bolts that elongate and continue to sustain a load, have been fabricated and tested. This device is an adoption of a concept originally developed in South Africa for use where unusually adverse conditions may warrant the added cost. How It Works A coupling in the rock bolt allows controlled elongation if the load increases beyond the bolt's design strength. (The load can build up either slowly, as during heaving, or rapidly, as before a rock burst.) The elon¬gation of one or more rock bolts surrounding a mine opening, allows the rock to move from its original position to c new position in a controlled manner. This movement relieves the rock stresses, and the mine opening reaches a new state of equilibrium. The elongatible coupling of the rock bolt consists of a

Jan 1, 1977

By J. S. Megahan

This report covers the design, fabrication and testing of the first and second generation mechanical scaling bars for more safely removing loose rack from mine roofs and walls. Included are discussions covering a survey of mine conditions and presently used hand scaling bar types as well as the design, fabrication and testing of the first and second prototype.

Jan 1, 1982

By Danny A. Riley, James R. Sanger, Hani S. Matloub, Michael Agresti, David Rowe, Lin-Ling Zhang, Yuhui Yan, Paula Galaviz, Judith Marchant-Hanson, Ji-Geng Yan

Until now there has been controversy about which tests should be performed to diagnose early Hand-Arm Vibration Syndrome (HAVS). Initial screening questions, especially about tingling and numbness, routinely given to patients prior to examinations proved to be a very important tool in the diagnostic process1, 4. However, standardized tests that are simple, quick, valid and reliable are needed to support a diagnosis of HAVS. Purpose: To find the most valid and reliable tests to diagnose HAVS. Material and Methods Five major tests were performed on Group I and Group II. Group I: Control group of 12 volunteers including students, nurses, secretaries and physicians with no history of using vibrating tools (age 20 to 50y, mean age 38.5y; 5male, 5 female.) Group II: 12 workers (age 17 to 65y, mean age 39y; 9 male, 3 female) were sent by a local trade union with a history of using vibrating power tools on their jobs for varying amounts of time (mean 12.2y, from 0.5 to 35y.) Pre-enrollment survey showed that each had more than 4 complaints commonly associated with use of vibrating tools (including numbness, tingling, weakness, pain, finger color or nail changes, temperature change, and difficulty moving.) 1. Sensory nerve conductive tests: Amplitude and nerve conductive velocity (NCV) were evaluated. 2. Cold Stress-Temperature recovery time tests were done on the index finger of the dominant hand following these steps: Confirm water bath is within 4-5º C. Place the finger temperature probe on pad of the index finger of the dominant hand. Record temperature every 15 seconds. Place subject’s hand in the cold- water bath for exactly five minutes. Record temperature every 15 seconds for ten minutes. 3. Blood test: Venous blood was taken by a 21-gauge needle with the yellow collection tube adapter. S-ICAM, Sera Thrombomodulin, Norepinephrine levels were evaluated by Henderson Research Centre, Canada. 4. Finger Sensory Evaluation: Semmes-Weinstein monofilament test and 2-point discrimination tests were performed on bilateral fingers. 5. Digital blood pressure test: blood pressure was measured in bilateral index fingers. Results 1. Median nerve sensory conductive amplitude from palm to wrist : GI: mean 96 ± 31µm; GII: mean 43± 30µm; for dominant hands. GI vs GII: P<0.001

Jan 6, 2006

By Harvey Patashnick

Current state-of-the-art microweighing technology represented by the Tapered Element Oscillating Microbalance (TEOM) is utilized as the basis for a new generation of Personal Dust Exposure Monitors (PDEM&apos;s). Two design configurations are presented. The first is an end-of-shift analysis system which uses small TEOM-PDEM cannisters that replace the filter cartridges in the current PDEM system. All other components carried by the miner (cyclone preseparator and pump) are the same. After the shift the TEOM cannister is plugged into an interface box which enables a minicomputer to automatically identify the unit, determine the dust mass increase during the shift, compute the shift average dust mass concentration, and print out and/or store the data. The second design is a real-time TEOM-PDEM system which is capable of operation over a 10-hour shift and on demand display real-time dust concentration level, time weighted average, and shift average concentration. As a result of the design study, a prototype end-of-shift analysis system was fabricated and delivered to the Bureau of Mines. A description of this system which consists of six TEOM cannisters, interface electronics and minicomputer is given. The system represents a significant advance in the dust monitoring program in terms or accuracy and automation.

Jan 1, 1983

By Philip Thompson

The Bureau of Mines investigated a selective flocculation-flotation technique to remove insoluble slimes from low-grade potash ore in a continous 45-kilogram-per-hour (100-pound-per-hour) process investigation unit (PIU). This research is part of the Bureau&apos;s program to improve resource recovery from low-grade ores. Results showed that 84 percent of the insoluble slimes were removed from an ore containing 5.5 percent water-insolubles and 14 percent K20 using a Bureau-developed, cationic flocculant-glycol ester-diesel oil reagent. Subsequent potash flotation recovered 75 percent of the potash in a cleaner concentrate assaying 56 percent K20. Concentrate leaching upgraded the product to market specifications of 60 percent K2O. An economic evaluation by the Bureau suggested that the rate of return on investment, after taxes, should be about 20 percent for such an enterprise.

Jan 1, 1980

By Radford B. Langston, John A. Marjerison, Graham C. Howell, Hendrik A. D. Kirsten

Probabilistic design is gaining wider acceptance in the rock engineering community since it allows more rigorous determination of risk relating to ground fall or excavation instability. Risk analysis can be conducted by various means, but the basis is formed by either objectively or subjectively determining probability of occurrence of an event. In the case of rock engineering, this event is either instability or excavation failure. Rock mass classification systems provide objective analysis of data collected on a typically subjective basis that also relate closely to excavation stability. A probabilistic analysis technique is presented that uses statistical distributions of rock mass and material properties, ground support fixture specifications, stress conditions, opening geometry, and ground support installation quality to more rigorously determine probability of failure for an underground opening and the subsequent risk to personnel.

Jan 5, 2007

By Winton Gale, David Oyler, Jinsheng Chen, Christopher Mark

The National Institute for Occupational Safety and Health’s (NIOSH) Pittsburgh Research Laboratory (PRL), RAG Pennsylvania and Strata Control Technologies of Australia have collaborated to conduct an extensive study of roof bolt strata interaction at the Emerald mine in Southwestern Pennsylvania. The primary goal of the project was to obtain detailed data on the interaction between the mine roof and the support elements for use in modeling studies. The study site was a longwall tailgate subjected to high horizontal stress. Three arrays of instruments were installed at the site, one in the tailgate entry and two in an adjacent crosscut. Pumpable concrete cribs were present in the tailgate array, and cable bolts were installed in one of the crosscut arrays. The instruments included mechanical and sonic extensometers for measuring roof movement, instrumented roof bolts, and three-dimensional roof stress cells. The study was ultimately successful in determining the magnitude of the horizontal stress concentration, the height of roof failure and the roof failure sequence, and the loading history of the primary roof supports.

By Edward L. McHugh, Stanley M. Miller, Jeffrey K. Whyatt

The point estimation method can be applied to the safety factor (SF) equation for any specified rock slope failure mode (such as plane shear, step path, or wedge) to obtain reliable estimates of the mean and standard deviation of the SF probability distribution. A gamma probability density function is recommended for modeling this probability distribution, because it allows only for positive values and is flexible enough to provide symmetrical shapes and right-skewed, exponential-type shapes for the SF distribution. The mean and standard deviation define this distribution, which then can be integrated numerically from 0 to 1 to obtain the probability of sliding, PS (portion of the SF distribution where SF < 1.0). The overall probability of failure, PF, for the potential slope failure mass is the joint probability that the rock discontinuities are long enough to allow kinematic failure (PL) and that sliding occurs along the rock discontinuities (PS); that is, PF = PSPL. This method for estimating the probability of sliding is extremely efficient computationally, and thus, expedites slope stability simulation routines used by NIOSH software to stochastically describe rock slope behavior and assist the engineer in designing catch benches for large rock slopes. Enhanced bench design translates into increased operational efficiency and safer working conditions in open pit mines and quarries.

By J. W. Town

This report summarizes the results of laboratory investigations made by the Bureau c! Mines on the recovery of mercury from caustic sulfide solutions by aluminum precipitation and by electrodeposition. Statistical methods were used to design the experiments and evaluate the resulting data. Precipitation studies demonstrated tint metallic mercury could be recovered from mercury sulfide-sodium sulfide solutions with aluminum. Other metals and their salts and aluminum, salts precipitated only black mercury sulfide. Over 95 percent of the mercury was precipitated from solutions prepared with reagent-grade chemicals and from cinnabar leach solutions. Two equivalents of aluminum were required to obtain 95 percent precipitation of the mercury. Under optimum conditions 1 gram of aluminum precipitated from 4 to 7 grams of mercury; the excess Aluminum was recovered for reuse. The effects of time and temperature on the precipitation of mercury were minor when compared with the effects of mercury concentration and aluminum equivalents. The particle size of aluminum had no significant effect over the ranges studied. When aluminum was used as a precipitant, the mercury concentration in solution was reduced to below 1.0 grams per liter. Adding arsenic and antimony sulfides to the mercury solution resulted in their coprecipitation with the mercury when the aluminum was added From 95 to 99 percent of both the arsenic and antimony were precipitated as metal, which amalgamated with the mercury.

Jan 1, 1962

By A. L. Foote

This is the final report of work accomplished during 1973-75 under U. S. Bureau of Mines Contract No. H0242015, "System for Handling Underground Mine Supplies and Materials." The purpose of the contract was to develop a mechanical device which could safely perform handling tasks that are normally done manually in underground bituminous coal mines. The report discusses studies leading to construct-ion of a battery-operated, three-wheel vehicle with a six-degree-of-freedom manipulator. Supportive design studies included collection and analysis of production, manual functions, and injury data on the underground bituminous coal mining industry. Transfer tasks in section storage and working places were the prime candidates for mechanical handling. Functional specifications were developed for two handling devices (one to handle existing unit loads and one to handle repackaged unit loads) and for a vehicle to mount the handling device. Design concepts for nine different handling devices were developed and a cost/benefit evaluation made for each. Detail design, capital and operating costs, and method improvement savings data were developed for two battery-operated vehicles and for two different manipulators. The three-wheel vehicle with anthropomorphic manipulator was chosen for development.

Jan 1, 1978

By Robert Stefanko

The following tables contain the average, maximum and minimum power parameter levels for several mining machines. Power factor is listed only for defined transducer output regions. The reasons for the undefined areas are provided in the Instrumentation Chapter. Several maximum voltage drops are included, and are computed from the no load line-to-line voltage: Again, the drops are from measurements at the low side of the load center. The machines are: Continuous Miners; F6A Alpine 76AM Jeffrey (d-c) 8CM Joy 8CM (10CM) Joy 9CM-2AH Joy loam Joy CU-43-2H Joy 2 each CM26H Lee-Norse CM28E Lee-Norse Shuttle Cars; 18SC Joy 48S Torkar (a-c) 2 - 10SC Joys input to rectifier 2 - 16SC Joys input to rectifier

Jan 1, 1973

By R. A. Vik

The influence of thermal treatments on the grindability of low-grade hematitic iron ores from Michigan and Minnesota was examined in bench-scale tests. Treatment factors were roasting temperature, roasting atmosphere, and ore cooling conditions. Bond ball mill grindability and work indices were used as response indicators in evaluating the condition of the ore. Of the three treatment factors evaluated, roasting atmosphere, which brought about the con version of iron oxides to magnetite, had the most significant effect; roasting temperature had the next most important effect; and cooling condition had the least effect. Optimum grindability was obtained with reduced-quenched products of both ores at 650° C, near the alpha-beta phase transformation of quartz.

Jan 1, 1971

By David A. Benjamin

At the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied prospects, claims, and mineralized sites in a 43,053-acre portion of the 51,262-acre Desatoya Mountains Wilderness Study Area (NV-030-l10) in 1985. The study area, located 50 miles east of Fallon, NV, is underlain by alluvial deposits of Quaternary age and volcanic and volcanic-derived sedimentary rock of Tertiary age. No mines or recent exploration activity were identified within the area studied. The Gold Basin area, located 1/2 mile to the south has produced 982 ounces of gold and 10,086 ounces of silver. The Cold Springs area, located 1/2 mile to the west, has recently been explored for gold-silver. Mineralization at these two areas apparently did not extend into the study area, but future mining at these areas would likely impact it.

Jan 1, 1986

By Jose P. T. Agapito

Several underground coal mines currently operating in the Beckley District of West Virginia are experiencing serious roof and floor problems. A significant portion of the estimated two billion tons of coal resources may be lost as a result of these ground control problems. Preliminary studies by the Bureau of Mines indicated that these problems are due in part to a high horizontal stress field. During this contract study, a field program was conducted to quantify the horizontal in situ stress. A total of 14 overcoring sites (using the Bureau of Mines strain-relief overcoring technique) in five mines were drilled producing 53 data sets. Analysis of the data was done to provide in situ horizontal stresses for each of the five mine, and for the district as a whole. Stress data indicate horizontal stresses far in excess of that predicted by theory and in some cases, up to six times the estimated vertical stress. In addition to the field testing, a detailed computer modeling study was conducted using finite element and boundary integral (displacement discontinuity) methods. Verification of in situ stresses was obtained by the models and analysis of various development geometries, mining methods and remedial techniques were conducted. Recommendations for reducing ground control problems and future studies are presented.

Jan 1, 1980

By G. L. Gates

The waters used to waterflood the Wilmington oilfield were studied by the Bureau of Mines, in cooperation with the city of Long Beach, Calif. Increases in the pressure of the injection wells indicated that they were being plugged by materials suspended in the waters. This study was made to identify the suspended materials, determine their origin, and find methods of preventing their formation. The suspended oil-coated materials were iron sulfide, barium sulfate, calcium carbonate, clay, and sand (or silica). Results indicated that the sulfide, which was as high as 90 milligrams per liter, was the product of sulfate-reducing bacteria. The injection of ocean water increased the sulfate content of the waters in the petroleum reservoirs from 3 to 250 milligrams per liter, thereby furnishing sulfate for growth of the bacteria. The waters were supersaturated with barium sulfate. Laboratory tests showed that sulfide could be removed from the waters by adding iron at a cost of 1 to 2 mills per barrel. The solubility of iron sulfide and calcium orthophosphate in the injection waters was also determined.

Jan 1, 1975

By E. R. Maize

This report is the third of a series on convergence of roof and floor in coal mines and subsidence of surface that accompanies it. The first papery dealt with extraction in a mechanized mine (Montour 10) having relatively short rib lines that retreat rapidly. The second 6/ dealt with extraction in a mine (Crucible) in which coal was loaded by hand and in which the rib lines were long and slow-moving. The present report deals with a mine (Gibson) in which conditions approximated those in the Crucible mine, except that the distance between room centers was considerably less and the pillars were narrower in consequence. Moreover, the average cover was less and the studies were made under the steep hillside of a stream valley compared with a gently rolling surface over the portions of the second mine studied. Gibson mine lies in the east-central part of Washington County, Pa., approximately midway between the Montour 10 and Crucible mines on a north-south line. A cooperative agreement covering the work was made with the Hillman Coal & Coke Co. through W. L. Affelder, vice president. This paper describes the methods used in the investigation, gives excerpts from the data obtained, and offers such generalisations as appear to be justified.

Jan 1, 1940

By Harold L. Rhodes

The Bureau of Mines has developed a method for determining the H2S content in natural gas samples. A gas chromatograph with a flame photometric detector was used to analyze samples with H2S concentrations ranging from 5,000 ppm to a minimum detectable limit of 0.01 ppm. A mass spectrometer was used to analyze samples containing H2S in amounts greater than 5,000 ppm. Methods are presented for preparing containers for H2S samples and for preparing standards using partial pressure and weighed standard methods, Sample collection techniques are discussed, as are analytical results which illustrate the loss of H2S while in the sample container and provide a basis for evaluating containers used for sampling and standard preparation.

Jan 1, 1979