Search Documents

By Steven J. Schatzel, William P. Diamond

Coalbed gas content measurements are commonly used in mine safety as well as coalbed methane resource assessment and recovery applications. Gas content determination techniques generally fall into two categories: (1) direct methods which actually measure the volume of gas released from a coal sample sealed into a desorption canister and (2) indirect methods based on empirical correlations, or laboratory derived sorption isotherm gas storage capacity data. Direct gas content determination techniques may be further. subdivided into quick-crushing and extended desorption methods. The quick-crushing methods are primarily used in mine safety applications outside the United States, but have also been used for resource recovery applications. Quick-crushing methods rely on crushing the coal sample soon after collection to release all the desorbable gas, thus significantly shortening the amount of time required for desorption measurements. However, some data useful for resource recovery applications are lost. Extended desorption techniques are most commonly used for resource assessment and recovery applications where information on desorption rates is useful for reservoir modeling, and for fundamental coalbed methane research. Extended desorption methods allow the gases in the coal sample to desorb under controlled laboratory conditions until a defined low desorption rate cutoff point is reached. The sample may then be crushed to measure the amount of gas remaining within the sample. Direct method techniques for gas content measurement are the focus of this paper.

By Jr. Flynn

"The Bureau of Mines receives and answers many requests for information on the qualities and properties of American coals, and also publishes many papers that deal with coal characteristics. Compilations of chemical analyses of coal from specific locations are contained in a series of technical papers,2/ by States, whereas typical analyses of coal seams, by States and counties, are given in data books, volumes 1 to 7,2/ by producing districts, as defined in the Bituminous Coal Act of 1937. Bulletin 446, ""Typical Analyses of Coals of the United States,"" condenses and supplements these data books, which do not apply to the Western States. Other coal properties are described in numerous publications listed in the Bureau of Mines Bibliography of Publications. However, no recent publication lists average B.t.u. values by rank on a Statewide and national scale. Averages have been estimated in the past, and some of them are included in this paper for comparison.The average and the ranges of as-received B.t.u. values of American coals on a Nation-wide basis, as found by the statistical method described in this paper, are given in table 2 and on a State-wide basis in table 3. The following is abstracted from table 2:In deriving average B.t.u. values for coals, the results depend on the type of data available and the methods of calculation. The data, or analyses, may represent any of three types of samples - mine, tipple, or delivered. In mine sampling, a channel cut is made of a vertical face of the coal bed, carefully excluding most of the impurities, and the material retained is the sample. It is readily seen that mine samples are selected samples and do not strictly represent the unmined coal bed, unless the coal contains no major impurities. Mine samples generally represent the best-quality coal that could be produced. In contrast to mine samples, tipple and delivered samples represent coal that actually has been mined, and their analyses may show either lower or higher values than mine samples of the same coal, depending on treatment and preparation after mining.Of the thousands of analyses accumulated by the Bureau of Mines, most are of either tipple or delivered samples and represent the coal after it has been mined. Any average calculated from this aggregate of data will, consequently, reflect coal that has been produced, and not unmined coal in situ.The method of calculating an average from the basic data also will have considerable influence. If there are three seams of coal in a county, the average analysis for the county is not necessarily the arithmetic mean of analyses of the three individual seams. For a probable average of unmined coal, the B.t.u. values of each seam should be weighted in proportion to the unmined reserves of each seam. In similar manner, an average for past pro¬duction should be weighed according to the past production for each seam. Figures for coal reserves are only estimates based upon geologic evidence and its interpretation. Production records are much more accurate than estimated reserves, although detailed production records for individual seams by counties are very few."

Dec 1, 1949

By R. V. Ramani, K. V. K. Prasad, M. Swaminathan

"INTRODUCTIONMine ventilation planning is an engineering design process requiring a substantial amount of qualitative knowledge obtained through experience. A concept for a knowledge-based ventilation expert system was developed by Ramani and Prasad (1987).1 11 An expert system based on the above scheme was conceived with the motivation of providing a tool to facilitate decision making for ventilation engineers in the context of computer assisted ventilation planning. Options for the implementation of the system were then examined and several commercial, personal computer (PC) based shells assessed toward this end. The options considered, the evaluation criteria and procedure arc discussed in Prasad ·and Ramani, (1989).Cll Following the above study, a scheme was developed to represent the components of the expert system.<3> Evaluation of several commercial shells indicated that there was none available which permitted interfacing with a large external algorithmic program. It was therefore decided to develop the KBS in LISP and custom build the necessary interfacing routines to ""hook out• to the network analysis program (NAP). Due to this choice of development strategy, the computer implementation aspects of the KBS arc important as all the interfacing components had to be developed with the basic tools offered by LISP.In this paper, the implementation of the knowledge based system (KBS), in terms of its component, the interfaces among the various components of the KBS and between the KBS and the user arc described. The ventilation KBS consists of an AES (analysis expert system), an IES (interpretation expert system)' and an algorithmic NAP (network analy5is program). The AES analyzes the input to the NAP considering the legal 5tipulations governing the various mine ventilation network parameters and principles of good ventilation, helping the ventilation engineer develop and represent represent the problem for solution by the NAP. The IES diagnoses the output from the NAP in terms of the critical parameters in the context of the given problem. Thi5 loop is continued till a satisfactory salution is obtained. The implementational details of the AES, the IES and the approaches to the validation of the expert system arc also discussed."

Jan 1, 1990

The object of this program was to design and build a self-contained system for remote monitoring of the atmosphere in mines. The system developed uses the mine pager phone line as the primary communication channel and also has the capability of using 208 Hz in the ELF band for wireless transmission through the earth. The depth for through-the-earth trans- mission is expected to be about 80 to 90 meters in high conductivity soil and is limited by the noise level in the ELF band-pass filters. The underground components of the TEM System are energized by mine power through a battery charger - storage battery power supply. In the event of mine power failure the battery capacity is more than sufficient for one week&apos;s operation with interrogations every four hours.

To develop and design a bit that will rapidly drill smooth and precise instrumentation holes in soft rock. Approach Use a one-piece bit made by combining a drag bit and a diamond bit. Because a smooth-walled borehole with a precise diameter is needed for borehole pressure cells (BPC) and other borehole instruments, a diamond bit is usually used. However, diamond bit drilling is slow, and the bit will tend to bind when squeezing ground is encountered. On the other hand, the drag bit will cut faster, but the walls of the drill hole will be rough and the diameter will not be as precise. The combination will provide a bit which penetrates as rapidly as a drag bit, but retains the smooth-wall and precise borehole diameter of a diamond bit. How It Works A three-foot-length of EW-size drill rod is centered in a diamond bit by welding it to three equally-positioned spacers at each end of the bit. A drag bit is attached to the EW rod with a standard EW-to-drag bit adapter as shown in the diagram. Three equally-spaced diamond inserts are set to the desired hole size and welded to the diamond bit barrel behind the crown. These inserts increase the smoothness and precision of the hole by cut-ting away any hole closure. Three equally-spaced shims are set approximately 0.020-inch under the overall insert diameter size and welded to the rear of the diamond bit barrel. The combination bit should be used on a diamond drill with either water, mist or air as the coolant.

Jan 1, 1982

Reduce potential for steering errors during tramming of articulated vehicles, particularly when the operator is seated to the rear of the machine pivot point and is tramming in reverse. Approach Position-sensing and feedback cylinders were applied to the steering cylinders of two S&S cleanup tractors to cause the steering-control lever to match the orientation of the vehicle sections. The vehicles were tested in two working mines. How It Works A position-sensing cylinder (see Figure 1, Item A) is attached to one of the steering cylinders in the cleanup tractor steering system. As the steering cylinder piston rod is actuated by movement of the control lever, hydraulic oil flows from the position sensing cylinder to the feedbck-cylinder (B), causing the feedback-cylinder piston and rod to move. The outside end of the rod repositions the the steering-control lever until its angular position corresponds to the orientation of the vehicle sections.

Jan 1, 1978

By Robert C. Hickman

"INTRODUCTION Two holes were drilled on the G. S. Stiner zinc prospect, in the Lead Mine Bend area of Union County, Tenn. The holes were drilled in the vicinity of an area of gossan float and were bottomed in the Maynardville formation of the Nolichucky shale. Drilling was started January 24 and completed February 16, 1947. The total footage drilled was 421.2 feet.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative Work, and prepares the final report. The Metallurgical Branch, Cliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the general supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch, Raleigh, N. C.LOCATION AND ACCESSIBILITYThe prospect is located approximately 20.5 miles southwest of Tazewell, Tenn. It is reached from Tazewell by driving 13.8 miles southwest on State route 33, thence 6.8 miles over graveled roads in a northwesterly direction to Stiner's general store. The drill holes are located in the bottom land northeast of the store (fig. 1 and 2)."

Feb 1, 1948

By Raymond F. Helinski, Linda J. McWilliams, Sean Gallagher, Thomas R. Battenhouse, August J. Kwitowski, John R. Bartels, Dean H. Ambrose

This report examines the boom arm vertical speed for roof bolting machines to study a moving boom arm appendage at different speeds during different work scenarios. The goal of this study is to determine the impact of the appendage speed on the likelihood of the operator&apos;s hand, arm, head, or leg making contact, such as touching the moving appendage. The overall research goal is to reduce workers&apos; risks to injury from exposure to underground mining machinery. Accident investigation reports from the Mine Safety and Health Administration do not usually contain enough information to aid in studying this problem, and lab experiments with human subjects are not feasible because of safety issues. As an alternative, researchers used a unique computer simulation model that uses a virtual human, vision tracking, and generates random virtual human motions and risky work behaviors. By using specialized software to simulate the computer model, researchers accurately identified potential hazards of tasks where it is not possible to perform experiments with human subjects. Results of a frequency distribution analytic approach show that, regardless of other variables, contact incidents were always greater when the boom was moving up, always greater on the hand, and always greater or the boom arm part of the machine. The reason why the subject experiences more contacts when the boom arm is moving up rather than down is that more risky behaviors occur during drilling and bolting when the boom is ascending. Results of a cross-tabulation analytic approach show that the 25th-percentile operators experienced more contacts than other operator sizes and had most of their contacts during a boom speed of 13 in/sec. The hand-on-boom behavior during drilling and bolting tasks experienced more contacts than other work behaviors, and both tasks had most of their contacts during speed 13 in/sec. The 60-in seam experienced more contacts than other seam heights and had most of the contacts during speed 16 in/sec. For univariate logistic regression models, seam height is the most important predictor of the probability of a contact. However, a multivariate logistic regression model predicted contacts are more likely with the both-knee work posture in the 60-in seam, a 25th-percentile operator compared to a 55th-percentile operator, and speeds 16 and 22 in/sec compared to 7 in/sec. Results of a survival analytic approach suggest that controlling the boom speed is the most important factor in determining the risk of an operator making contact. Based on the data collected, boom speeds greater than13 in/sec result in a substantial increase in risk to the roof bolter operator making contact. Speeds less than or equal to 13 in/sec are associated with a more modest relative risk of making contact, which represents a decrease in potential hazard. Virtual operator&apos;s response time has little effect on the number of contacts experienced. The mining industry can use the information in this study to reduce the likelihood that roof bolter operators will experience injury due to contact with a moving roof bolting machine&apos;s boom arm.

Jan 5, 2005

By M. D. Schlesinger

Experimental data for coal hydrogenation are presented to show that when a vehicle oil produced from coal is present, coal is hydrogenated to the same high conversion whether molybdenum catalyst is impregnated on the coal or intimately mixed with the slurry. Differences in product distribution could be related to the severity of operating conditions. No minimum mixing time was established, but 2 hours was sufficient. Longer periods of mixing, to 14.75 hours, had no effect on the results. The hydrogenation conditions were in the pressure range of 8,500 to 10,000 p,s,i. at 400° to 500° C. Most of the experiments were made in duplicate. The results were obtained with molybdenum concentrations of 0.01, 0.1, and 1 percent. Al the mentioned pressure range and a time at temperature of 15 to 60 minutes, coal conversions higher than 98 percent were obtained.

Jan 1, 1962

By Leon E. Esparza

The Bureau of Mines studied 780 acres of the 24,130-acre Sheldon Contiguous Wilderness Study Area (CA-020-1012) in 1985. The study was done at the request of the Bureau of Land Management and authorized under the Federal Land Policy and Management Act (Public Law 94-579, October 21, 1 976) in order to evaluate the mineral resources. The study area is located in Washoe County, NV, about 35 miles northeast of Cedarville, CA. A search of county courthouse records and an examination by foot traverses through and adjacent to the study area did not reveal evidence of any mining or mining exploration activity past or present. In addition, evidence of any form of rock alteration was not observed. Evidence of mineral resources is not apparent. Although basalt, the only rock-type present in the study area, can have some limited industrial applications, sources closer to potential markets probably would preclude rock from this area being economically competitive. INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of the Sheldon Contiguous study area at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will be used to help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. Although the immediate goal of this and other USBM mineral surveys ;s to provide data for President, Congress, government agencies, and the public for land-use decisions, the long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

By J. W. Paul

A superintendent is one who has the oversight and charge of some organiza- tion or enterprise, with porer of direction. The superintendent of a coal mine is the official who is in general charge of conducting the operation of the nine for the purpose of producing coal; he is accountable to his superiors for all matters that relate to the cost of production and safety in operation, ed under him are all the underground officials and other personnel making up the mine organization. The responsibility of the superintendent covers all the principal phases of mining, purchases of materials, issuance of supplies, accounting, and upkeep of the property and equipriont. In a broad sense, the superintendent must view his job as embraced under four gneral heads: (1) Construction, (2) instruction, (3) supervision; and (4) discipline. The degree of efficiency with which each of these phases of his work is conducted is a measure of the safety factor which the superintendent injects into his job. Injury to workmen and damage to property may be due to neglect of one of these general headings; as for example in the collapse of a scaffold there has been faulty construction which may be found upon investigation to have been the result of faulty instruction or lack of instruction. It may be that the condition of the scaffold was not ascertained in advance of its collapse through faulty supervision, or the discipline of the workmen had been neglected.

Sep 1, 1930

By Kathleen J. D?Amico

THIS SUMMARY is identical to the summary given in volume III of this series of mineral production in the United States (including Alaska and Hawaii), its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico and of the principal minerals imported into and exported from the United States. For further details on production see commodity and area chapters. A summary table comparing world and United States mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers [ ]

Jan 1, 1958

By Anthony Iannacchione

One of the more pressing engineering problems for deep longwall mines in the Southern Appalachian Basin is to design longwall systems that will eliminate catastrophic coal pillar failure from the working environment. The purpose of this study is to quantify the behavior of a particular size abutment pillar prone to burst or bump. Because the 24.4-111 (80-ft) square abutment study pillar is within the pillar size commonly used in this region, understanding the behavior of this pillar should aid in future efforts to design optimum mining strategies. This research has attempted to construct the pillar stress and roof-to-floor convergence profiles in order to evaluate the ultimate strength, deformation modulus, visco-elastic deformation, and violent failure characteristics of the pillar during longwall mining. This information reflects the overriding influence of the local geologic characteristics on bursts, provides the field measurements needed to verify concurrent modeling studies, and suggest some basic mechanisms associated with the coal pillar bursts discussed in this paper.

By Joseph A. Sutton

The prospect of utilizing bacteria in mining and metallurgical processes introduces a new and challenging area of investigation. Elements of bacteriology and metallurgy are discussed in connection with possible areas where biological science might be applied in extractive metallurgy. Bacteria may prove important in the selective separation of metals from ores and metallurgical solutions, the production of sulfur from gypsum or pyrites, and the production of sulfuric acid from elemental sulfur. A series of reports concerning the experimental applications of bacteria on minerals and metallic ores will follow this paper. For several years the Bureau of Mines has been investigating the action of bacteria in the oxidation of sulfide minerals and their potential uses in metallurgical processes. Primary attention has been given to the possible utilization of certain strains of autotrophic bacteria that live in industrial leaching solutions or fractures of mineral outcrops. The purpose of this paper is to acquaint the mining and metallurgical engineer with micro-organisms and some of their possible applications in the field of extractive metallurgy.

Jan 1, 1961

Minimize airborne respirable quartz dust produced by continous mining machines. Approach Install a shovel-mounted underboom water spray system on the off-curtain side of the mining machine. Dusty air containing quartz is momentarily trapped under the boom, where it is captured by fine spray mist. The remaining dust cloud is directed immediately behind the curtain before it can migrate back to the machine operator&apos;s location. How It Works Previous studies have shown that most of the dust generated by continous mining machines occurs under the boon as the cutter head shears down. The primary source of respirable quartz dust on many continous mining operations is cutting or trimming roof rock immediately prior to shearing. This results in very high concentration , of

Jan 1, 1989

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

Computer input data for an operating mine is developed on the basis of a detailed ventilation survey which includes air quantity, air quality, pressure loss and fan performance measurements. Quantity measurements must be reviewed extensively and assumptions made about leakage quantities and airflow paths. Pressure measurements must be reviewed and developed into a pressure gradient for the mine system. Air quality measurements are used to determine methane sources and amounts. Finally, the fan test data is used to develop the correct fan characteristic curve. Quantities and pressure losses for each branch in the system are used to calculate the branch resistances which are then utilized in the ventilation simulator to model the mine system. QUANTITY BALANCE The quantity of air coming into a mine based on field measurements will rarely equal the quantity exiting the mine, even if allowances are made for methane or compressed air input to the system. The same statement can be made for airflow through any isolated part of the mine ventilation system such as individual working section or main aircourses leading to an area isolated from the rest of the mine. The reason for the apparent discrepancies is the accuracy of the indicated quantities which in turn is based on the accuracy of the individual velocity and area measurements. Even with measurements following the guidelines described in the previous section on quantity measurement, this error can only be minimized but not eliminated. As a result the ventilation system must be carefully balanced so that, for any loop, the quantity in plus any methane or compressed air injection will equal the quantity out. The continuity of flow described by the balanced system must approximate the

Jan 1, 1977

By Sean Gallagher, Thomas R. Battenhouse, August J. Kwitowski, John R. Bartels, Dean H. Ambrose

Problem: Incident investigation reports do not usually contain enough information to aid in studying boom arm vertical speed for roof bolting machines to determine the impact that appendage speed had on an operator&apos;s risk of experiencing a contact. Laboratory experiments with human subjects are also not feasible because of safety and ethical issues. Method Researchers successfully developed a three-dimensional computer model that uses virtual human simulation software as the primary means to gather contact data when the boom arm touches the operator&apos;s hand, arm, head, or leg. Results: Data analysis of roof bolter simulations shows that the speed of the boom arm is the most important factor in determining the risk of an operator making contact. Regardless of other variables, contact incidents were always greater when the bolter arm was moving up, greater on the hand, and greater for the boom arm part of the machine. The reason why the subject experiences more contacts when the boom arm is moving up rather than down is that more risky behaviors occur during drilling and bolting when the boom arm is ascending. Based on the data collected, boom speeds greater than 13 in/sec result in a substantial increase in risk to the roof bolter operator of making contact. Speeds less than or equal to 13 in/sec are associated with a more modest relative risk of making contact, which represents a decrease in potential hazard. Impact on Industry: The use of such information can be quite helpful in making recommendations to machine design and task procedures to reduce the likelihood that roof bolter operators will experience injury due to contact with a moving roof bolting machine&apos;s boom arm.

By C. K. Rose

A hydraulic scaling rig was placed in operation at the Bureau of Mines oil-shale mine near Rifle, Colo., in 1953. The rig consists of a self-leveling platform mounted on a hydraulic-powered boom. The boom is mounted on the bed of a diesel truck. The equipment provides a movable work platform from which two men can work in safety and comfort while barring loose rock from the backs and walls of the rooms, pillars, and haulageways. INTRODUCTION As a part of its synthetic liquid fuels program the Bureau of Mines has developed a mine in the richer oil-shale beds of the Green River formation near Rifle, Colo. An important part of the work of the Oil-Shale Mining Branch is investigation of techniques for low-cost mining of oil shale on a commercial basis. It is evident that scaling loose rock from the high backs and walls of the mine represents a portion of the direct mining cost. This paper describes the development of a scaling rig for operation in the upper heading of the mine, which is 39 feet high.

Jan 1, 1954

By Lippe D. Sadwin

This report describes a high-speed streak camera technique for measuring the lateral shock pressure generated by a cylindrical explosive charge detonated from one end. Experimental data show that the magnitude of the lateral pressure is approximately 50 percent that of the pressure generated from the terminal end of the charge for three explosives studied.

Jan 1, 1965

By James P. Bennett

To improve construction materials for emerging chemical and metallurgical technologies, the Bureau of Mines is investigating the acid resistance of ceramic materials. In the study described here, eight commercial ceramic materials comprising two red shale, two fire clay, a silica, a silicon carbide, a carbon, and a high-alumina brick were evaluated. Samples were exposed to 20 wt-pct HC1 at 50° C for 110 days. The test apparatus designed to evaluate the materials is described. Changes in chemical and mineralogical composition, cold crushing strength, volume, and weight, and leach rates of AI, Ca, Fe, K, Mg, Na, Si, and Ti ions were monitored. In general, the statistically significant physical property changes that occurred were small. In many cases, no changes were detected.

Jan 1, 1982