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By Wm. F. Netzeband

"The mode of ore occurrence and the methods and costs of mining at one of the zinc-lead mines in the Tri-State zinc and lead district, Oklahoma, are presented in this paper for the information of mine operators in other districts.No. 2 mine property was acquired by lease in 1918 after some 30 holes had been drilled and a shaft had been sunk to the 305-foot level by the first lessees. After acquisition of the lease, the present operating company drilled a rich ore body on the 260-foot level and in 1920 started sinking two shafts. Production was begun late in 1921, and the mine has been operated more or less continuously to the present time.The mill has a capacity of 400 tons in 10 hours, the usual length of the mill shift in the district.The geology of Mine No. 2 is very similar to that of Mine No. 13 except that the Cherokee shale is thicker, ranging from 80 to 160 feet, and all the formations are correspondingly deeper, the Short Creek oolite horizon here being at a depth of about 300 feet. The oolite has not been found on this property, but the lime comes in at about the level at which the oolite should appear.The ore deposits of Mine No. 2 occur in the brecciated and bowlder ground above the Short Creek oolite. The main or 260-foot level is about 40 feet above the oolite horizon, and the lower or 300-foot level is immediately above it.The ore deposition is controlled by a zone of shearing and fracturing, and the mineable areas are divided into two distinct runs which have a northwest trend with a lean or practically barren area dividing them. This characteristic has controlled the mining to a large extent, for it enables the mine superintendent to locate the large pillars in lean ore and leave only small pillars in the richer ore. Figure 1 shows the outlines of the ore body and the pillars.The ore on the main level occurs disseminated throughout the jasperoid breccia as patches or lenses in the jasperoid, or cementing massive bowlders of jasperoid breccia and chert. The ore of the lower level is more of the bowlder type than that on the main level and occurs chiefly cementing the bowlders but also with some disseminated ore in the jasperoid breccia.The gangue minerals are jasperoid breccia, chert, and dolomite. Calcite is found in minor quantities. Sphalerite is the principal ore mineral; galena is found only in minor quantities around the edges of the ore body. When galena is encountered in this ore body, the limit of the ore can be expected.The exploration and estimation of ore reserves at Mine No. 2 are similar in many respects to the methods used at Mine No. 1.4After the mine was opened up and the general character of the ore deposit had been determined, drilling operations were concentrated along the trend of the shear zone. Later drilling has proved what appears to be a parallel shear zone or an offset of the zone now being mined."

May 1, 1929

By J. C. Kerkering, S. M. Miller, P. C. McWilliams

Researchers at the U.S. Bureau of Mines investigated the use of close-range photogrammetry and subsequent stereo digitizing to obtain data from rock fracture roughness profiles. The photogrammetric process yielded results that were acceptable but somewhat inferior to those obtained by a mechanical profilometer. On the basis of this study, further pursuit of photogrammetry as a data collection method in mining is proposed. Fractal geometry was investigated as a means of measuring the roughness of rock fracture profiles. Four fractal algorithms were used: divider method, modified divider method, box method, and spectral method. A comparison of the methods gave ambiguous results. Brown's modified divider method provided the best means of obtaining the fractal dimension. Shear strength estimates were obtained using the parameters of the modified divider method and Myers' Z, measure. Because of differences in results when comparing the different ways of obtaining the fractal dimension, future users of fractals in studies of rock fractures are advised to cross-check their results carefully.

Jan 1, 1993

By Mark K. Larson

A constitutive model for rock interfaces based on the principles of static fatigue is proposed. The model is applicable to weak rock or joints with cohesion. Friction and dilation are decreased as plastic work increases. At equilibrium, the creep time increases by one time-step interval, and interface cohesion at each node decreases according to a power function. A constant-load, direct-shear simulation showed that the model is cap- able of mimicking constant-rate and tertiary creep and predicting failure. Tests on core from a coal mine showed constant-rate and, sometimes, tertiary creep, but also weak transitory creep. The cohesion deterioration function may need modification to simulate primary-phase creep. If model parameters are known for a site, the model can predict the onset of tertiary creep and failure. Such predictions can help engineers make better entry design and support decisions, which will reduce the likelihood of roof falls and increase safety for underground miners.

Provide an unobstructive means of measuring small changes in distance from roof to floor or from rib to rib of a mine opening and the rate of closure in order to help operators of under-ground mines detect hazardous ground conditions. Approach A small ultrasonic measurement system was developed to detect g round movement and define closure rates. How the System Works The system contains two parts: a transducer and a readout device. The small ultrasonic transducer, similar to an audio speaker diaphram, is plucked with an ultrasonic frequency every six seconds. This frequency wave is sent through the air and reflected back to the transducer off any surface at which the transducer is pointed. The amount of time needed by the ultrasonic wave to make this round trip is accurately measured using a precise oscillator / timer and is converted into a measure of distance. The accurate 6-second time interval is used to convert any subsequent changes in the reading to a rate of change in feet per minute. Two readings are then displayed alternately on the readout instrument.

Jan 1, 1984

Mining and the related extractive and processing industries are chiefly responsible for America's high standard of living. Enormous quantities of sand and gravel, limestone, copper, iron and a myriad of other mineral commodities are required to sustain our growing nation. However, the mineral deposits, both domestic and foreign, are becoming increasingly difficult to find. Adding substantially to the problem, is the fact that the conditions are worldwide. Foreign politics are increasingly affecting mineral commodity availability. Figure 1, taken from Bureau of Mines, "Status of the Mineral industries 1976" illustrates our dependency (in some cases total) on foreign sources for vital mineral commodities. While few nations are capable of exerting an OPEC-like influence on any one mineral commodity, the threat of cartel arrangements and related control strategies is evident. Nationalization of entire industries, once they become self-sufficient, is also exerting a disruptive influence on a large portion of the mineral industries.

Jan 1, 1977

By E. E. Buban

A self-contained breathing apparatus has been developed to provide complete respiratory protection for a miner in an irrespirable atmosphere. The apparatus has the desired features of comfort, reliability, maintainability, and quick-donning capability. The apparatus is packaged in a moistureproof envelope and is protected in a shock absorbing, fiberglass resin carrying case. The apparatus is a small, lightweight, one-time-use device that can be readily worn on a miner's belt, requires no maintenance and is designed to have a shelf life of five years and a carrying life of three years. It is deployed to the use position in a period of 15 to 30 seconds. Man tests conducted in-house and at the National Institute of Occupational Safety and Health (NIOSH) testing laboratories established that this unit meets all performance requirements listed in the Code of Federal Regulations, Title 30, Part 11, Subchapter B, Subpart H (CFR 30, Part 11) for respiratory protective devices. The unit, which has received joint approval (TC-13F-37) on a prototype basis from the Mining Enforcement and Safety Administration (MESA) and NIOSH has: (1) Ten-minute service life under escape conditions. (2) Thirty-minute service life when the wearer is at rest. (3) Peak-to-peak breathing resistance of less than our inches water column height. (4) Inspired gas temperature of less than 135°F. (5) Breathing gas contents greater than 19.5 volume per cent of oxygen and less than 2.5 per cent carbon dioxin. (6) A weight (complete in carrying case) of 2.75 lbs. (7) A carrying case size of 6-1/2"x 5-1/8"x 3-1/8".

Jan 1, 1974

By David J. Kusler

This study is an appraisal of the feasibility of recovery and the possible chemical and physical uses of the limestone from the Greenbrier Formation in western West Virginia. Data on minability, occurrence, quality, and markets were obtained from published and unpublished sources and by a limited mail survey combined with personal contacts. The estimated costs of recovery by deep mining techniques are considerably higher than competitive surface and shallow subsurface operations. Compositional in formation available for this study was limited but indicated the suitability of the limestone for most physical uses and some chemical process uses in appraisal of the uses and demand reveals that immediate markets may be difficult to establish, but for some uses long-term prospects may be encouraging, especially if the quality of limestone would be suitable for lime manufacture or use as metallurgical fluxstone.

Jan 1, 1968

By John P. Borovsky

A 3-year study was conducted to evaluate the problems and benefits of using vegetation to stabilize tailing from a potential Minnesota copper-nickel milling operation. The project consisted of three separate investigations: a waste characterization study, a greenhouse study and a field study. With few exceptions, the physical and chemical characteristics of the tai ling were found to lie within the range of properties of Minnesota soils. The tailing lacks organic matter; is deficient in nitrogen, phosphorus and potassium; and may contain elevated levels of soluble salts and heavy metals, particularly copper and nickel. Numerous grasses, forbs and woody plants will tolerate the tailing as a rooting medium. Peat incorporation and topsoil dressing provided few benefits to the revegetation process which were not provided by a fertilizer application. With fertilization, grass/legume production in the tailing was comparable to local agricultural yields. Concentration of heavy metals in grasses grown in the tailing were generally below suggested tolerance limits for plants and animal forage. Legumes tended to accumulate higher concentrations of copper and nickel, and metal uptake of most plants was positively correlated with rate of fertilization. Tailing drainage water contained elevated levels of heavy metals, and establishment of vegetation had little effect on the quantity and quality of tailing drainage water. However, topsoil dressing significantly increased drainage water volume when compared to unvegetated control plots. Copper-nickel tailing revegetation recommendations were developed.

Jan 1, 1983

By Paul G. Swanson

This investigation was conducted to identify the principle causes of spoil instability problems in the Eastern Coal Province. The study was also conducted to develop a matrix to predict the strength and groundwater parameters necessary to conduct stability analyses on a proposed reclamation scheme. Suggestive methods to reduce spoil instability potential are also included. Numerous physical property, strength, compressibility, chemical and mineralogical tests were conducted on mine spoil samples obtained from 11 different surface mine sites. Site characteristics that influence the position of the post reclamation groundwater table were identified. Distinct regions within the Eastern Coal Province with high incidences of surface mine slides or high landslide susceptibility were identified. The application of the predictive matrices developed in this study is for surface mine sites mined and reclaimed in general accordance with the Surface Mine Reclamation Control Act of 1977. A review of current mining practices and the relative effect on spoil stability is included.

Jan 1, 1983

By Oliver Bowles

"Simple systematic accounting that adequately records all transactions has long been regarded as essential to the welfare of any business enterprise. Some of the defects that detract from the prosperity of the slate industry are attributable to a lack of effectiveness in cost keeping. This condition has prompted the United States Bureau of Mines to make a detailed study of accounting methods for the slate industry, and to present for consideration a system of accounts, which it is believed would enable the industry to attain more economical management and operation if accepted by a fair proportion of its important units.The method of accounting presented herein has been worked out with the assistance of leading slate producers and the recommendation are tentative and are submitted in this form as a means of developing constructive criticism. Believing that cooperative effort in this, as in many other problems, will bring the most enduring benefits to the industry as a whole, the writer urges that the most earnest consideration be given to this vital problem now facing the slate industry.Grateful acknowledgment is made of the helpful assistance rendered by R. E. Eckert of the accounting firm of Eckert, Degan, and Palmer of Easton, Pa., in compiling the charts and the explanatory text. He has brought to this work a wide knowledge of accountancy, supplemented by a background of direct contact with the slate industry, and his presence at the various conferences has been of great advantage in clearing up difficulties. The National Slate Association sponsored the cost study and chiefly through the efforts of President W. H. Smith and Secretary W. S. Hays, has aided greatly in conducting it. Acknowledgment is also made of assistance rendered by William F. Marsh of the United States Bureau of Mines."

Nov 1, 1929

By A. T. Iannacchione

Underground limestone mines typically use the room-and-pillar method of mining in the generally flat-lying limestone formations. In some cases the dip may exceed 5° which can result in unique roof instability problems. Stability may be further exacerbated by the presence of horizontal tectonic stresses. Field studies and numerical model analyses are combined to assess the affect of the dip in various stress conditions. The results showed that where the horizontal tectonic stresses are sufficient to cause intact rock failure, increasing dip results in increased failure potential. The effect of the dip is greater when the maximum horizontal stress is parallel to the dip. Two case studies are presented and evaluated against the findings of stress analysis results. The study showed that the empirical rules of orienting headings parallel to the maximum stress are generally applicable to dipping excavations, except when mining in the up-dip direction. The importance of accurately determining the orientation of the maximum horizontal stress is emphasized because the window of favorable orientations relative to the stress is small.

By Curtis H. Elder

In studies conducted by the Bureau of Mines, two test areas were hydraulically stimulated and exposed by mining: One in the Pittsburgh coalbed at the Vesta No. 5 mine, Washington County, Pa.; and one in the Illinois No. 6 coalbed at the Inland mine, Jefferson County, Ill. Induced fractures were contained totally within the coalbed with no adverse effect on the stability of associated rock strata. Induced fractures were vertical and were propagated normal to the direction of least residual tectonic stress. Gas production was increased fivefold to twentyfold by hydraulic stimulation.

Jan 1, 1977

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag composition. Liquidus and solidus temperatures and solid solubilities were determined for the BaF2-Y203 system, and the information is presented as the phase diagram. The phase diagram was constructed from data obtained by ceramography, X-ray diffraction, and thermal analysis of specimens encapsulated in small molybdenum ampoules. The data indicate a simple eutectic system with maximum terminal solid solubilities of less than 1 mole pct. The eutectic temperature is 1,343° C, and the composition of the eutectic is less than 1 mole pct Y203.

Jan 1, 1970

Improve the Bureau-developed system for locating and communicating with miners trapped underground following a mine disaster. Approach Include in the wireless system a portable second-generation transceiver that is more reliable, compact, easier to deploy and operate, and ruggedized to withstand a mine environment. How It Works In an emergency, the new transceiver is snapped onto a caplamp battery for power. (Normally the 1 1/2-pound transceiver is either carried by the miner or is strategically located in the mine.) Its antenna wire, coiled inside the transceiver container, is removed and deployed in a roughly square configuration around a coal pillar or on the mine floor. The antenna consists of 300 feet of lightweight wire, which provides a large magnetic moment while remaining intrinsically safe, The photograph shows the

Jan 1, 1981

By Robert L. Lappi

Eight interburden handling concepts are developed for multiple seam area mine stripping operations in central and western United States. They are based on data gathered and analyzed during field surveys, literature reviews and visits to state requlatory agencies in five states. It is concluded that improvement of reclamation practices through selective interburden handling techniques is possible at lower operating costs than currently incurred. Specific multiple seam mining systems are discussed in this report.

Jan 1, 1980

By James A. Wasson

Because of the danger to life and property in a coal mine if an oil or natural gas well should be accidentally intersected during mining operations, certain precautionary measures should be carried out prior to entering previously unmined areas. The locations of all wells both at the surface and at the depth of the coalbed should be accurately determined. The condition of the well should be learned from surface observations, and more importantly, from subsurface examination by geophysical logging devices where possible. It is also desirable to learn the physical properties of the hydrocarbon-bearing rock formation and the hydrocarbon fluids. The major hazard presented by oil or natural gas wells to mining operations is that of explosion and fire due to the rapid release of gas into the mine atmosphere. Wellbore pressure, the principal index of danger, should be determined by one or more of the methods described and by a service company such as those listed in the appendix. Because of high pressures involved and the consequent hazard, much emphasis has been placed on underground storage of natural gas in areas containing minable coalbeds. Maps are shown of the principal coal producing areas and the locations of currently active gas storage reservoirs. A checklist has been included of factors to be considered when mining coal in an area where oil or gas wells exist.

Jan 1, 1973

By H. E. Peterson

Rhenium occurs in very small quantities (12).4 In order for the Federal Bureau of Mines to conduct an investigation of rhenium sources and methods of extraction, it was necessary to devise improved techniques for detecting and measuring minute quantities of the metal. A modification of the procedure of Malouf and White (46) was developed which can be used to detect rhenium in concentrations as small as 0.1 part per million and can be used to measure quantities of 1.0 part per million. It can be used for the analysis of siliceous and calcareous ores, of molybdenite concentrates, of fumes, of flue dusts, and of other metallurgical products. Development of the method involved devising an amine extraction procedure for separating rhenium from all interfering elements except tungsten and a selective distillation procedure for separating rhenium from tungsten. Adoption of these separation procedures permits use of large samples and precise determination of rhenium by colorimetric analysis of the thiocyanate complex of rhenium by means of a spectrophotometer.

Jan 1, 1961

By H. Miller

In recognition of the need for a portable low-profile hard rock crusher, the Bureau of Mines sponsored the development of such a unit capable of moving up as the face advances. By allowing primary ore reduction at or near the mine face, the advantages of conveyor haulage From the face as demonstrated in soft ore and coal mines, could be realized for hard rock Brines as well. This report presents the results of a development and testing program for such a portable low-profile crusher, designed by Eagle Crusher Company and called the M44. The unit has an extremely low vertical profile considering its size and capacity. The crushing jaws, which form the crushing lumber, are inclined, with the lower jaw mounted for eccentric movement relative to the stationary upper jaw. This provides efficient crushing while also forcing material through the crushing chamber. As a result, the inlet feeder can be disposed horizontally. To facilitate correct processing of different materials, the size of the discharge opening and the action of the movable crushing jaw are variable. The unit also incorporates a feeder hopper and discharge conveyor that provides for efficient ore handling through the machine. Tests demonstrated the M44 Crusher's high capacity, efficiency and reliability. During testing, it crushed over 120,000 tons of materials of up to 32,000 psi compressive strength at production rates in the 200-350 tons/hour range. The unit operated smoothly under simulated low-headroom conditions, and Proved readily transportable.

Jan 1, 1983

By H. H. Fields

The Bureau of Mines is in the process of degasifying a virgin area in northern West Virginia from the base of an 839-foot-deep vertical borehole¬. An in situ gas pressure hole 199 feet long, and seven degasification holes ranging in depth from 500 to 850 feet (average 618 feet) were drilled in an 8-foot-thick virgin Pittsburgh coalbed from the enlarged (14-foot-diameter) bottom of this borehole. The in situ pressure at the back end of the hole and the range of gas and water flows from degasification holes as they were completed and closed off were 203 psi, 79,000 to 257,000 cfd (average 160,000 cfd), and 5 to 8 gpm per hole (average 6.8 gpm), respectively. Twenty-four hours after the seven holes were connected through individual water traps to a common collector for natural venting of the gas through pipes to the atmos¬phere, the total gas and water flows and the in situ pressure dropped, respec¬tively, to 971,000 cfd, 1.3 gpm, and 18 psi. Eighty days later the correspond¬ing values dropped to 529,000 cfd, 0.50 gpm, and 13 psi. After 180 days of degasification, 91 million cubic feet of gas had been removed from the affected virgin area. This represents 60 to 70 percent of the gas calculated to be contained in the area of coal affected by the holes.

Jan 1, 1973

By J. C. Gerdeen

It is of upmost importance to keep the size of the program to a minimum for the computer being used. One way is to reduce the size of the data bank by adjusting the large common array A in the main program (page, line 32) and the statement following the assignment of A. The current value of A is 35001 and is optimized for the UNIVAC computer with 5,000 words of useable storage. Another way to reduce the required storage is to overlay the program. That is, to have in the computer only the subroutines which are being used. In large finite element codes, overlays or segmentation of the program is a necessity. The code presented here has three levels of segments and are presented graphically in the tree in Figure D-1.

Jan 1, 1976