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By A. F. Colombo

In an effort to maintain an adequate supply of iron to meet national economic and strategic needs, the Bureau of Mines, U.S. Department of the Interior, is conducting research on methods for beneficiating the oxidized taconite resources located on the western Mesabi range in Minnesota, thus expanding domestic iron ore reserves. The selective flocculation and cationic flotation process was investigated in a pilot plant using an ore feed rate of 410 kg/hr (900 1b/hr) and 88 percent recycled water. Lime and a cationic flocculant were used to clarify the waste slurries treated in the water reclamation circuit. An oxidized taconite assaying approximately 36 percent Fe yielded concentrates averaging 63.5 percent Fe and 4.3 percent SiO2 and having an average iron recovery of 84.4 percent. The estimated reagent cost per tonne of concentrate was approximately $1.10. In an attempt to recover more of the iron lost in the flotation tailing, wet high-intensity magnetic (WHIM) separation was incorporated in the pilot plant circuit. The flotation concentrate grades obtained from beneficiation circuits with and without WHIM scavenging were similar, but when WHIM separation was used the overall iron recovery was increased by 2 to 9.5 percent, depending on the iron assay of the flotation tailing.

Jan 1, 1978

By Suzann C. Ambrosio

The mineral industry in Burundi continued to be a minor contributor to the 1980 gross domestic product (GDP) estimated at $293 million in constant 1970 prices.2 Mineral export revenues, primarily from cassiterite, increased by a factor of 15 between 1979-80, reaching approximately $434,000 by yearend 1980. Gold, bastnasite, colombite-tantalite, and wolfremite continued to be exploited on a small scale, using manual and semimechanical methods. Despite a sharp decline in mining activities during 1979, attributed to a lack o? profitability and shortage of construction materials, the mining sector exhibited signs of recovery during 1980. The mineral exploration budget grew 32% over 1979 levels and was equivalent to approximately $42,000 in 1980. In addition, the Burundi Geographical Institute (IGE BU) was created in September 1980 and given responsibilities to collect cartographic, topographic, hydrogeologic, and other geomorphological data., SONIBUROM, the Burundian and Romanian Government joint mineral corporation, conducted mineral deposit inventories during 1979-80 and has been charged with exploiting some of these as yet unspecified resource areas. Another Burundian-Romanian effort, called Mabaya-Butahana, was initiated to search for gold deposits. Meanwhile on the Ruzizi plain, alluvial gold prospecting, with an estimated grade between 0.2 to 1.0 gram per ton, was carried out on a small scale.

Jan 1, 1982

By Paul Sands

Single- and two-stage tests were made with 6-inch, coal-cleaning hydrocyclones to determine the effect of hydrocyclone geometry, operating conditions, and feed composition on performance. Most of the testing was conducted in an open-circuit pilot plant that had a maximum capacity of about 9 tons per hour. The coals used in the investigation had top sizes of 1/4 inch and 28 mesh. Considerable latitude was found in the range of geometry variables that could be used without affecting performance adversely, although a certain minimum ratio of overflow to underflow openings had to be maintained for best operation. Two-stage cleaning proved distinctly better than operation with a single hydrocyclone, because clean coal lost in the refuse product of the primary unit can be partly recovered in the secondary. There is an unusually great difference in the specific gravities at which the individual sizes of the feed are separated in the hydrocyclone. This militates against high efficiency because maximum yield occurs when all sizes are cleaned at the same specific gravity. The size composition of the feed and, more particularly, the size composition of the impurity have a greater influence on the efficiency attainable in the hydrocyclone than in most other types of fine-coal cleaners.

Jan 1, 1968

By T. F. Anstett

The Bureau of Mines investigated the availability of platinum from known major deposits in market economy countries. Fifteen of these deposits contain demonstrated resources totaling 302 million troy ounces of platinum. Detailed geologic, engineering, and cost evaluations were performed on each deposit to determine its potential for platinum production. There are large amounts of demonstrated platinum potentially available from market economy deposits that were not analyzed owing to lack of adequate data or to technological limitations. These include 297 million troy ounces contained in the UG2 and Platreef of the Bushveld Complex, South Africa. This analysis indicates that about 11 0 million troy ounces (2.3 million ounces annually) of platinum are potentially available at the January 1980 producer price of $420 per troy ounce, nearly all from South Africa. An additional 85 million troy ounces occurring in Zimbabwean deposits would become available only through more than a quadrupling of that price. In order to meet projected world demand of 3.5 million troy ounces in 1990, platinum price may have to increase. Only one domestic deposit, the Salmon River in Alaska, is capable of producing platinum at $420 per troy ounce. Regardless of price, at assumed production capacities, domestic deposits could supply less than 10 percent of annual U.S. requirements.

Jan 1, 1982

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's hand, arm, head, or leg making contact, such as touching the moving appendage. The overall research goal is to reduce workers' 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'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's boom arm.

Jan 5, 2005

By R. M. Santmayers

[This paper presents one of a series of digests of foreign mining legislation that is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the mining legislation of Bulgaria was prepared from a copy (in French) of the Mining Laws of Bulgaria, promulgated by Royal Decree No. 33 of I. arch. 31, 1910, and published in the "Journal Official," No. 83, April 14, 1910, and checked against a digest prepared by Maynard B. Barnes, First Secretary, American Legation, Sofia, Bulgaria, dated June 10, 1932, which was transmitted through the courtesy of the Department of State. CLASSIFICATION OF MINERAL SUBSTANCES Mineral deposits are classed either as mines or quarries. (Art. l.) Tunes are deposits, the products from which must be processed. Under this class specific mention is made of the metals (gold, silver, copper, lead, zinc, iron, chrome, titanium manganese, tungsten, tin, mercury, platinum, cobalt, nickel, cadmium, aluminum, molybdenum, bismith, uranium, antimony, arsenic), sulphur and other "analogous" mineral substances, phosphate rock, iron pyrites, sulphates, saltpeter, alum, boracic acid and its compounds, talc, asbestos, amber, graphite, merschaum and precious stories of all kinds, reek salt and other salt, peat, coal, petroleum, ozocerite, asphalt and all other bituminous substances. (Art. 2.)]

Jan 1, 1933

By M. Townsend, E. L. Petsonk, H. Abrons, E. Daniloff, K. Kinsley

Workers exposed to certain inhaled dusts may show increased levels of nonspecific airways responsiveness (AR). In some studies, cigarette smokers have also been reported to have increased levels of AR. As part of an ongoing study, we compared the results of preshift methacholine inhalation challenge, spirometry, and smoking and occupational histories, in 191 under-ground bituminous coal miners (M) and 215 non-mining control workers· (C) . All M and c were selected to have normal baseline% predicted FEVI (PPFEV). Mining tenure was recorded as years worked underground (YRUG) and at the coal face (YRFC). AR was assessed as the% decrease in FEVI from baseline divided by the dose of methacholine delivered. M reported similar years smoked (YRSM) but fewer pack-years* (PY) than c~ Overall, both increasing YRSM and PY were associated with more AR*. Smoking C* but not M showed increased AR with increasing PY. In smoking and nonsmoking M, baseline AR and PPFEV showed no association with YRUG. The level of AR was inversely related to YRFC*, possibly representing selection away from dustier jobs. AR was inversely correlated with PPFEV*. In this study, AR and baseline PPFEV were not significantly associated with mining tenure, but cigarette smoking was related to both baseline lung function and level of AR. * p < 0.05 (Supported in part by Grant Gll35142, us Bureau of Mines, Generic Mineral Technology Center for Respirable Dust.)

Jan 1, 1989

By D. B. Dow

In collecting and dissctinating inforr:.at'ion on ir.:,provec.. practices us0i in the pr eduction cf petroleur:1 and in the r;:;.:.1.nuf __ cture of gasoline, the Bureau of Mines ha.s aidei in creatin5 an interest i-n efficient 11:ethods in all phasas of tr.e oil ani gi:i.s iniustry. In the refinin£ ir...mstry ther.:: is a growing tend.ency for incre.:l.sea. effi. ,:;iency, ana inforr;.Eition rela:tin!s to ic:;p·roved practices should be of value not only to the larger and. core efficient plants, but particularly to srr.a.11 refineries unable to carry out a lar6e experLnental pro!§.rarn. The refi?eries of the United States required 4.3,915,029 barrels cf crude oil J.uring the year 1920*, inclu.::.in1:, 611136,210 barrels of Mexican cru::...e. This yielded. 4,8821546,599 gallons of E>asoline, a.n avara.t;,e ciaily pro;.iuct1on of 13,340,291 e,allons·, Besides the easoline obtainel fro;., cruie· oil by-fr:;.cticna.1 distillation and. from heavy oils by crackini:,, this a,-r;ount incluC1.es 3,152,924 bar­rels of natural-ga.$· gasoline blended. With asoline fro,., th otha two sourcs.

Apr 1, 1922

GLOSSARY TERM DEFINITION ACCOMODATION The process by-which the eye changes focus from one distance to another. ADAPTATION The process by which the retina adjusts-to more or less light then it was exposed to during an immediately preceding period. Also involved, to a lesser degress, is the change in the size of the pupil which regulates the amount of light entering the eye. Adaptation results in a change in the sensitivity of the eye to light. CENTRAL VISION (FOVEAL) The seeing of objects in the central or foveal part of the visual field. It is approximately two degrees in diameter and permits seeing much finer detail than does peripheral vision. DIRECT GLARE The effect of brightness or brightness differences within the visual field sufficiently high to cause annoyance, discomfort, or loss in visual performance. FOOT CANDLE A measure of the amount of light falling onto a surface. FOOT LAMBERT A measure of the amount of light that is being reflected by a surface. GLARE The effect of brightness or differences in brightness within the visual field sufficiently high to cause annoyance, discomfort, or loss in visual performance. LAMP A generic term for a man-made source of light. By extension, the term is also used to denote sources that radiate in regions of spectrom adjacent to the visible.

Jan 1, 1976

By Lloyd A. Morley, Alan M. Christman

Presented below is a review of how the objectives, as outlined in the statement of the problem, were achieved. 1. Methods of evaluating the performance of grounding systems must be described. These methods are the subject of Chapter III. 2. Field trips to operating mines should be undertaken, and a cri¬tique of their grounding systems made upon the basis of obser¬vation and the application of the above techniques. An analysis of field trip data, along with practical recommendations, is in¬cluded in Chapter IV, while a complete review of all field trips is given in Appendix I. 3. Because of their thoroughness, present coal mine regulations should be evaluated, and their applicability to open-pit environ¬ments appraised. This has been done in consultation with governmental agency, manufacturing, operating mine, and consult¬ing engineers. As stated in Chapter IV, insight gained through field observations has served to amplify and extend the base of knowledge from which the recommendations were made. 4. The results of these investigations should lead to suggested Federal standards. Such recommendations comprise Appendix II. In addition, several important factors, which are discussed in Chapter IV, were brought to light as a direct result of the field research. 5. Seasonal variations in the earth resistance of ground mats, as illustrated by Table 12, reinforce the need for periodic

Jan 1, 1976

By Lloyd A. Morley, Alan M. Christman

General A review of the literature has revealed important areas which should be investigated during the field work. Of the utmost importance is the safety of mine personnel. Should a phase-to-ground fault occur on a shovel or other piece of equipment, current may return to the substation through the machine&apos;s contact surface with the mine floor, thereby raising the frame above ground potential and posing a shock hazard to anyone who touches the equipment. If the frame-to-earth resistance is very low, then no dangerous potentials will be developed, and a basis for elimination of the ground conductors from trailing cables could be postulated. However, should the contact resistance be high, then lethal voltages could be present on the machine frame. In this instance, low-resistance ground conductors in the trailing cable would be a necessity. Therefore, field tests should include measurements of the earth resistance of electrically operated portable or mobile mining equipment such as shovels, draglines, and drills. When the electrical distribution system is subject to lightning discharges, the grounding grid must safely carry to earth and dissipate enormous current surges. It is essential that the grounding grid have a low value of earth resistance, because any potential developed across the grounding grid as a result of current flow will appear on the frames of all machinery connected to the grid. Thus, an earth resistance

Jan 1, 1976

The coal deposits in Alaska occur in several major coal fields or basins. The deposits underlie about a quarter of the state, an area larger than Montana. Approximately 60 percent of the coal is bituminous and 40 percent is subbituminous. Less than one percent is lignite or anthracite. Although known coal reserves are estimated at only 6.1 billion tons (about 1.25 percent of U.S. reserves), estimates place the hypothetical reserves at 5.5 trillion tons and the identified reserves at 170 billion tons. The differences are due to limited exploration programs within the state. Conditions affecting mining and reclamation are unique to Alaska because of its extreme northern latitude. For example, permafrost occurs in about 75 percent of the state; tundra vegetation occupies vast treeless regions; and the climate is characterized by extremely cold winter weather and a short summer season. In addition, hydrologic conditions are considerably different from those in other states; major streams fed by silt-laden glacial melt water contain greater concentrations of natural sediment than the effluent discharge limits permitted by federal regulations. Also, some coal field locations are subject to potentially high seismic risk. These factors make coal mining and reclamation in Alaska more difficult than in other states. Alaska&apos;s program to regulate surface coal mining was approved May 2,1983. The Abandoned Mine Lands program was approved December 23,1983.

Jan 1, 1992

By Maria I. De Rosa

Table 28 and figure 10 show the number of fires and fire injuries for surface sand and gravel mines by state during 1990-2001. Table 28 also shows the injury risk rates, employees&apos; working hours, and lost workdays. At surface sand and gravel mines, a total of 70 fires with 60 injuries occurred in 29 states during 1990-2001. Fifty-nine of the fires caused 60 injuries (none of the fires involved contractors). The yearly average was 5.8 fires and five injuries. The Ewhr value was 741 x 106 hr (Irr = 0.016), and the LWD value was 6,921. California had the most fires (nine fires and five injuries), followed by Michigan (six fires and six injuries) and Pennsylvania (five fires and five injuries). Of these states, Pennsylvania had the highest injury risk rate value (Irr = 0.052). Table 29, partly illustrated in figure 11, shows the number of fires, fire injuries, risk rates, employees&apos; working hours, and lost workdays by time period. The number of fires and fire injuries show an increase during the second period followed by a decrease during the fourth period followed by a small increase during the fifth period and a sharp decrease during the last period. Employees&apos; working hours increased during most of the periods. The Irr values follow patterns similar to those shown by the injury values.

Jan 1, 2004

By Robert C. Hickman

"INTRODUCTION The Big Four fault and the Sandy Creek fault, with several cross faults, traverse the Stalion-Curnel fluorspar prospect in a northeasterly direction. The Big Four mine, about three-quarters of a mile northeast of the prospect, is the only active mine in the immediate area.A resistivity survey was made of a portion of the prospect by the Division of Geophysical Exploration, Bureau of Mines, in May and June 1946. As a result of this survey, five holes were drilled by the Bureau of Mines during the period from October 8 to December 16, 1946. Two Longyear No. 12 Junior Straitline diamond drills were used for the work.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective 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 Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the supervision of Mitchell H. Kline, chief, Raleigh Branch, Mining Division."

Mar 1, 1948

By Thomas J. Peters

The U.S. Bureau of Mines studied the 3,500-acre Winegar Hole study area, Idaho, a legislatively proposed (101st U.s. Congress) addition to the Winegar Hole Wilderness, Wyo.; it adjoins the western boundary of the Wilderness at the Idaho-Wyoming border, about 15 m; east of Ashton, Idaho. The study was part of an Idaho Land Assessment Program to provide minerals information for land-use decisions, and ensure domestic mineral supplies. The study area is an east-west elongated, wooded plateau south of Falls River. Although the area is covered with surficial glacial deposits, it is probably underlain by volcanic flows; light-colored and mafic flow rock were noted in sparse outcrop. No mines, prospects, mineralized areas, or mineral resources were found in the study area during a literature and field search. The only nearby prospects include geothermal and rock aggregate (volcanic cinder) sites, and several placer claims. Although the Winegar Hole study area lies within a region of potential geothermal resources, no evidence of geothermal activity was observed. Rock in the area does not split into flat slabs, which could be useful as dimension stone, and would require crushing to be used 8S aggregate. Alluvium (placer) samples contain less than SO.01 per cubic yard gold (at a $350 per oz price); alluvial deposits are too small to contain gold resources.

Jan 1, 1992

By H. Robert Ensminger

The Belizean economy had an estimated annual growth of about 3.4% over that of 1986. Economic growth during the 2 previous years was slower and was characterized by a negative trade balance. The gross domestic product (GDP) was an estimated $200 millioni2 in current dollars. Limited natural resources and scarce finances continued to make the Government&apos;s task a difficult one. Belize and China signed an economic cooperation agreement in April under which the Chinese Government is to provide technical assistance, a cash grant of $60.000, and a long-term, interest-free loan of approximately $1.5 million. In May, it was reported that gold was discovered in a remote area of the Maya Mountains in western Belize. An estimated unassayed value of $400 million has been placed on the deposit by one of its discoverers. However, the government in Belmopan has played down the discovery. Two U.S. oil companies. Seahawk Oil International of California and Alston Oil Co. of Texas, were granted licenses to explore for oil. Seahawk Oil will explore a large area of the Orange and Corozal Districts, while Alston Oil will prospect a 90,000-acre area of the western Cayo District. Another U.S. oil company, Pecten Oil Co., recently completed seismic studies off-shore of Belize City. Pecten Oil has made plans to start drilling in 1988.

Jan 1, 1989

By W. E. Lamont

The Federal Bureau of Mines conducted research to develop methods of removing phosphorus from the earthy, calcareous hematite ores of the Birmingham, Ala., iron district while simultaneously improving the grade and recovery of the iron values prior to furnacing. An attempt was also made to identify the phosphorus minerals present in the ores. The ores contained about 36 percent iron, 12 to 16 percent CaO, 15 to 20 percent hydrochloric acid insolubles, and 0.30 to 0.36 percent phosphorus. Fractions containing 5 to 15 percent phosphorus were isolated from the ores. Collophanite, Ca3P2O3?nH2O, a member of the apatite group, was the only phosphate mineral identified. Beneficiation methods using flotation and reduction roasting with magnetic separation yielded good grade iron concentrates, but were not as effective for reducing the phosphorus content of concentrates. Reduction roasting followed by fine grinding, magnetic separation, and acid leaching gave iron concentrates containing 62.5 percent iron and 0.04 percent phosphorus with an iron recovery of 82.9 percent and a phosphorus rejection of 93.7 percent. Reoxidation of reduced magnetic concentrates followed by acid treatment gave iron concentrates containing 58.1 percent iron and 0.02 percent phosphorus with 89.6 percent recovery of the iron and 96.5 percent rejection of the phosphorus.

Jan 1, 1973

By Yael Miron

ANFO blasting agents may undergo an exothermic reaction when they contact warm ore bodies that contain pyrite and its weathering products. The reaction is very fast at temperatures above 80° C. Urea, when present in sufficient amounts, inhibits this reaction at temperatures below 180° C. But urea-ammonium nitrate mixtures are very hygroscopic and, in certain climates, may be difficult to handle in the field. Reaction-inhibiting characteristics of three compounds were reported by the Bureau of Mines in 1979. Recently, the Bureau investigated the reaction-inhibiting qualities of five additional compounds. Mixtures of ANFO, pyrite, weathering product, and prospective inhibitors were slowly heated, under conditions simulating a hot borehole, to determine prospective inhibitor capability at temperatures up to ~175° C. Small-scale thermal tests of the same mixtures were used for verification and clarification of results. Two organic compounds, phthalimide and xanthine, similar in structure to urea, failed to inhibit the reaction. Zinc oxide and calcium carbonate were found inferior to urea, though zinc oxide raised the onset of reaction from 80° C to about 140° C. Only magnesium oxide was found to be similar to urea in its inhibitory ability at temperatures below 175° C. Based on results from analysis of quenched residues, the use of more than 5 wt-pct magnesium oxide is recommended.

Jan 1, 1982

By T. W. Goodman, J. Cervik

The Bureau of Mines conducted studies to compare the effectiveness of the cross-measure borehole system with that of surface gob holes on two successively mined retreating longwalls in the Lower Kittanning Coalbed. Only the cross-measure system was in operation on panel A; on panel B, both systems were in operation. In addition, the cross-measure bore-holes on panel B were drilled parallel to the face, whereas those on panel A were drilled at a 45O angle with respect to the longwall axis. The studies show that the cross-measure system captured 71 pct of the methane generated by longwall mining on panel A. On panel B, the sur- face gob hole dominated over the cross-measure system for about 700 ft (213 m) after it was intercepted. Beyond that point, the cross-measure system dominated. About 93 pct of the methane generated on panel B was captured by the two systems. Cross-measure boreholes that were drilled parallel to the face were as effective as boreholes oriented 45" with respect to the longwall axis. In addition, they are shorter and require less drilling time. Comparison between observed gas pressure differentials in boreholes and calculated values indicate that boreholes can be shortened further to 140 ft (43 m). Additional studies are needed to verify these calculations.

Jan 1, 1986

By Jr. Hardy, H. Warren Shen

"A study is presently underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which would make it possible to carry out remote monitoring of coal cutting operations. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal breakage and cutting procedures. The present paper will focus on the test facilities, experimental techniques, and results associated with linear, single-bit cutting. An AE-transducer, attached directly to the bit, detected AE signals during the cutting process.Experiments have been carried out on seven specimens of coal obtained from the USBM experimental mine at Bruceton, Pennsylvania. Three separate cuts were made for each of two bit angles (10 and 45 degrees) and two bit velocities (0.085 and 0.169 cm/sec), for a total of 12 separate cuts. Data associated with resulting particle size distribution and AE characteristics (major dominant frequency components) will be discussed. Data analysis has also been underway using a computer-based pattern recognition system known as ICEPAK (Intelligent Classifier Engineering Package). This program is able to evaluate over 100 features of an AE event and to make objective comparisons between AE signals associated with different loading or cutting parameters. The results to date show that AE generated during some of the test conditions can be recognized by ICEPAK with a recognition rate of 90% and higher while other conditions cannot at present be separated with a suitable recognition rate. Further analysis of the experimental data is presently underway.The reduction of the severity, and eventual elimination, of Coal Workers' Pneumoconiosis (CWP) depends on gaining fundamental understanding in a number of major areas. These include dust generation and entrainment, transportation, suppression, medical effects of dust, and possible treatment. At present a project is underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which would make it possible to carry out remote monitoring of coal cutting operations. Suitable on-line analysis of monitored AE data would allow engineers to evaluate factors such as shearer bit conditions and cutting efficiency, and to quantify the particle size and shape distribution of the generateddust. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal cutting procedures. To date experiments have been carried out on coal under uniaxial compression, linear single-bit cutting, and cutting using a laboratory-scale, single-bit shearer. A brief outline of the overall study has been presented in an earlier paper (Hardy, Shen and Kimble, 1995). This paper will consider the linear single-bit cutting studies in more detail.It is generally accepted today that most solids emit low-level seismic signals when they are stressed or deformed. In this paper this phenomenon will be referred to as acoustic emission (Hardy 1972, 1981, 1989). In essence, the measurement of AE activity in a field or laboratory structure is relatively simple. A suitable transducer is attached to the structure, the output of the transducer is connected to an associated monitoring system, and the AE signals occurring in the structure, due to internal or external stress, deformation, and failure are suitably acquired, pre¬processed and recorded."

Jan 1, 1998