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By İlknur Erol

The abstract highlights that hearing loss is an occupational disease caused by noise exposure in the workplace. The study investigates noise-induced hearing loss among miners in underground coal mines in Turkey, considering factors like occupation, age, and exposure time. The research employs logistic regression analysis to reveal the relationship between hearing loss and these factors. The findings suggest that occupational groups and duration of noise exposure significantly affect hearing loss. Miners in production groups and those exposed to noise for 10-14 years have a higher risk. The study concludes that age does not significantly increase the probability of hearing loss.

Mar 24, 2022

By Z. T. Bieniawski

The efficient and safe design of room-and-pillar coal mines still remains as one of the pressing problems facing the mining industry in the United States. Although much research has been directed to stability of mine roofs and coal pillars, no generally-accepted design method has been formulated. This paper presents a concise procedure for an improved design of room-and-pillar coal mines. Developed as a result of a three-year research effort, the methodology includes essentially three aspects: (i) determination of stable roof spans; (ii) determination of the strength of coal pillars; and (iii) determination of safety factors for room-and pillar coal mining in the United States. It is shown that the presented approach will lead to a greater recovery of coal by a more economical, yet safe, mining operation. Design charts and tables are presented and a step-by-step design procedure for practical mining engineers is explained. Several examples are included demonstrating the use of the proposed design procedure for room-and-pillar coal mines.

Jan 1, 1983

By Jeremy Maurer, Duah Philip, Awuah-Offei Kwame, Donya Otarod

Land use impact assessment for mining is time- consuming and expensive. Because of mining’s impact on biodiversity, land use assessment methods that evaluate biodiversity are important for mining land use impact assessments. Remote sensing, in particular satellite multispectral sensing platforms such as Sentinel‑2 and the Landsat mission series, have been used to assess and quantify biodiversity through proxy variables such as NDVI (Peña-Lara et al., 2022). The objective of this paper is to present results of a comparative study of land use and biodiversity based on multispectral satellite observations and production data from copper and cobalt mining in the Democratic Republic of Congo. We quantify the relationship between different spectral bands and vegetative indices and the production data provided by the mining companies and measure correlations. The results suggest that remote sensing could be a cost- effective means of assessing biodiversity impacts of mining.

Feb 1, 2025

By Bright Oppong Afum, Kojo Boakye, Kwaku Boakye

This research developed and simulated a novel multi-indicator Fatigue Detection and Alert System (FDAS) designed to enhance fatigue detection accuracy in mining environments. The system integrates a comprehensive set of inputs: eye blink rate, eye closure duration, yawning frequency, distraction levels, Pre-shift Check-in Scores (Self-report) and Electroencephalography (EEG) Levels. Using MATLAB’s Fuzzy Logic Rule Viewer (FLRV) and Simulink, simulations demonstrated the FDAS’s robust ability to process these diverse physiological and behavioural indicators accurately. It effectively classified operator fatigue into low, moderate, and high fatigue levels, consistently providing appropriate outputs and corresponding intervention recommendations across various mixed-signal scenarios. The system achieved a calculated accuracy of 85.19% across 27 test entries, with a standard deviation of approximately 1.8459, confirming its reliability for real-time fatigue monitoring. These findings highlight the significant potential of this fuzzy logicbased approach to proactively identify early signs of fatigue, substantially enhancing safety and operational efficiency in demanding mining operations.

Feb 22, 2026

By Sterling S. Cook

The U.S. Bureau of Mines is conducting core leaching experiments with sulfuric acid on oxide copper ores from the Cyprus Casa Grande and ASARCO Santa Cruz deposits in Arizona to further our understanding of the leaching process in supergene copper ores as it relates to in situ mining. Leach solutions from atacamite mineralization contained 5 to 30 g/l copper and few extraneous ions. Leachant from chrysocolla ores, with grades similar to the atacamite, contained 2 to 9 g/l copper and abundant extraneous ions. Quartz and K-feldspar had no impact on leach solution composition at any acid concentration (up to 40 g/l) while illite and sericite had minimal impact. Biotite, calcium-rich clay and limonite have a significant impact on solution chemistry when there is abundant free acid in solution. High acid concentrations increase acid consumption in ores with abundant biotite and limonite gangue. High acid concentrations can be used in ores with quartz, K-feldspar, and sericite gangues without increasing acid consumption per unit of copper removed.

Jan 1, 1988

By E. J. Duggan

In the course of the grinding experiments conducted at Climax over the past twenty years one interesting phenomenon was discovered. This was that balls made of certain types of steel grind more ore than some others. The most significant variation was found in the results secured with a hard alloyed forged bail compared with the forged carbon ball supplied by most ball manufacturers These findings were confirmed in many repeated controlled tests. The value of these tests depends on the methods used, the facilities available and the care with which the investigations were conducted. These are described in the following. This testing has largely been done in eight 91 x 81 low discharge ball mills in closed circuit with 7811 duplex screw classifiers. The mills run at 20 RPM on a feed approximately minus 3/8 inch. The ore is ground through 28 - 35 mesh in one stage. Each mill and auxiliary classifier is in a separate, parallel grinding and flotation section The, ore to each: section is the same in every particular and is fed to each mill bin from a common conveyor tripper. The ore from the bin to the ball mill is weighed on a conveyor scale. The power input to each mill motor is determined with a watt hour meter which measures the power to the mill motor only. Both the scales and meters are checked periodically by standard methods and have been found to give consistent readings. Automatic samplers are employed on each section to obtain accurate measurement of the size reduction. A size analysis of the classifier overflow is made each shift and a composite size analysis is obtained from a weighted average of the various shift analyses. The mills are driven by 450 horsepower synchronous motors so that there is no speed variation and shell liner age is kept as nearly the same as possible in mills under test. The same set of operators is assigned to a mill under test as to the control mill. In all other particulars such as ball load, mill density, liner design, etc., the mills are operated in precisely the same manner. This is an ideal arrangement for plant testing. From observations of ball mill performance over the past twenty years, it is the opinion of the operating staff that variations of as little as one to two percent in mill capacities may be determined if sufficient operating hours are devoted, to a test. Relations between mill capacities, fineness of grinds and power consumptions have been established with a high degree of accuracy. In Table I are given the figures for one test. These show that while the grind with the hard ball was slightly coarser, the tons ground per hour was 5.4 percent greater with the soft ball, and 6.1 percent greater on the basis of minus 100 mesh produced. The power consumed per ton with the hard ball was 4.4 percent greater on a tons per hour basis. The soft ball was inferior in wearing qualities and steel consumption per ton of ore was 24 percent greater with it. In this test the mills were charged with the two different balls for a period of three months to allow the ball loads to come to equilibrium. In Table II are given the specifications of the two balls. The difference in grinding rates may be accounted for by the nature of the ball surfaces. The surfaces of the soft balls after being worn a while are rougher to the touch. Enlarged photographs of the worn-in surfaces of hard and soft balls are shown in Figure I. These show the presence of scratches or skid marks on the hard ball surface which indicates less nipping effect. The Climax ore pulp has a pH of 6.0 and is in a dispersed state. The viscosity is low compared with most ores especially those that are conditioned with lime. This would lower the tendency of the pulp to adhere to the balls with a lower grinding efficiency as a result. It was also thought that the relative rates of wear from surface to center might affect the make-up of an equilibrium ball charge. This probably has little effect on capacity as shown by the size analyses of the two ball charges in Table III. This hypothesis was subsequently investigated by the use of rationed charges. The rationed charge did not overcome the advantage in

Jan 1, 1958

By Joseph Padgett

Of all the fossil fuels produced in the U. S., coal is by far the most abundant. U. S. reserves amount to an estimated 1.5 trillion tons, 2,500 times the 600 million tons produced in 1970. Although it would not be possible to recover all of this coal economically with current mining technology, a significant portion would be available given the proper circumstances. With existing technology, approximately one-eighth of these reserves is accessible, an amount which would last for several hundred years at the 1970 level of production. On the face of it, this substantial reserve should go a long way in meeting the Nation's energy needs. But coal offers special problems. As additional coal is mined and then burned, there are increased costs to the Nation's land, water, skies, and health. Hence, coal poses a dilemma because of its dual status as one of our most abundant domestic fuels and as one of our major sources of environmental degradation. Against the benefits that would be chalked up in the areas of national security, balance of trade, and economic well-being from the increased use of coal, we must enter on the debit side of the ledger the increased environmental cost. This paper reviews the use of U.S. fossil fuel, the drawbacks of coal as an energy source, the means being developed to overcome these drawbacks, and the background behind the present sulfur emission regulations relative to coal combustion. It also discusses in detail the Federal Environmental Protection Agency's (EPA's) current policies to ensure the continued use of coal as a major source of energy for fossil-fuel fired power plants.

Jan 1, 1973

By Gary W. Hudiburgh

The gangue in some magnetite ore bodies contains feldspar; the alkali content of the feldspar reduces the usefulness of these iron ores. One method of decreasing the feldspar content in magnetite concentrate is froth flotation. The amine flotation of feldspar from magnetite concentrate was investigated using zeta potential measurements, Hallimond tube flotation tests and laboratory-scale flotation tests. The zeta potential of various feldspars (microcline, albite, anorthite, oliqoclase and anorthoclase) were determined as a function of pH; the point of zero charge ranged from pH 1.4 to 2.5. Hallimond tube flotation tests using two amine reagents were conducted on the feldspars. Hallimond tube flotation tests using six amine flotation reagents were performed on the cobber tails (quartz, albite and microcline) from a magnetite concentrating plant; in all cases, over 85 percent flotation recovery was obtained at pH 8 and 10-5 to 10-4 [M] collector addition. Laboratory-scale (667 grams) flotation tests were performed on the magnetite concentrate in an attempt to float the feldspar which had reported to the concentrate. The effects of three different collectors, two levels of collector concentration, three pH levels, starch and HF acid were investigated.

Jan 1, 1975

By C. H. Perbix

[On Pier D in the Port of Long Beach, California, the Port of Long Beach has built a new bulk cement distribution terminal. The facility is operated by Pacific Coast Cement Corporation, who designed the complex and leased it from the Port of Long Beach on a 40-year lease. At one bulk cement is unloaded from vessels carrying from 12,000 to 30,000 t. The unloading is performed with pig speed mechanical unloading equipment and delivered into a concrete silo complex with, a capacity of 50,000 t. From the silos, bulls cement is loaded into trucks for delivery. The facility was completed in September 1981.]

Jan 1, 1983

By W. B. Greer

The performance of seals in boreholes, shafts, and tunnels is an important concern in mine safety, in the control of effluents from operating and abandoned mines, and in the underground containment of hazardous wastes (Einarson and Abel, 1990; Mining Waste Study, 1988). Despite the clear need for effective seals, few documented test results are available concerning the performance of in-situ seals. Some evidence indicates that horizontal or near-horizontal holes are especially difficult to seal properly (Kelsall and others, 1982). This research involved the installation, extensive hydraulic testing, removal, and post-test examination of a l0-cm-long by 10-cm-diameter cement grout seal in a near-horizontal borehole in limestone. The work was performed in an underground mine on Marble peak in the Santa Catalina Mountains, Arizona. A test hole was diamond cored in the re-crystallized limestone of the Escabrosa formation. The hole is 33.24 m long, 10 cm in diameter, and dips at 10.4 degrees. The hole extends between two drifts and thus is accessible from both ends.

Jan 1, 1992

By P. Kawahata

Newmont?s Twin Creeks Mine, located in northern Nevada, is producing gold ore from surface mining operations. The ore is currently processed at three different on-site facilities depending on ore type and grade. Processing facilities operate under stringent geochemical blending constraints that must be met from mine ore deliveries and off-site sourced ore. To analyze various strategic options, the technical team utilizes the mathematical optimization approach. However, due to the size and complexity of the operation, there are unique challenges in optimizing life-of-mine production scheduling. This paper describes those challenges and methods developed to take advantage of different scheduling software to effectively compensate each other and result in reasonable guidance. This paper also describes how those scheduling results are reflected in detailed mine plan and cost estimate work.

Jun 1, 2013

By Kent Phillips, Meredith Scaggs-Witte, Emily Sarver, Cigden Keles

"After nearly four decades of decline, the prevalence of coal workers’ pneumoconiosis (CWP, or black lung) in the United States has been on the rise since the mid-1990s (Laney et al., 2014; Laney et al., 2010; Suarthana et al., 2011; Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2016). Particularly alarming is the number of cases of rapidly progressive disease such as progressive massive fibrosis (PMF) (Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2016; Laney et al., 2017). A recent study by Laney et al. (2017) observed 192 U.S. coal miners participating in the Coal Workers’ Health Surveillance Program (CWHSP) who had been diagnosed with PMF since 2000. Of the 163 (85 percent) that had a normal radiograph on file to use as a baseline, 27 (17 percent) of these individuals had progressed from a normal radiograph to PMF diagnosis in less than 10 years. Moreover, 162 (84 percent) of the individuals in that study worked in Kentucky, West Virginia or Virginia, and 169 (88 percent) had only ever mined underground. Blackley et al. (2016) also reported on a group of 60 PMF cases that were discovered by a single black lung clinic in eastern Kentucky. Since seeking care at such clinics and participation in the CWHSP are voluntary, and could be influenced by a number of factors, there has been some concern that these reports may overestimate the degree of resurgence in severe disease (i.e., versus disease that was previously under-reported). Even so, they highlight a critical need to better understand the cause(s) of disease development and progression — such that effective interventions can be devised.The notable uptick in CWP and PMF rates among miners in central Appalachia has led to this region being called a hot spot for disease (Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2014; Laney et al., 2017). While the geographic clustering has been well documented (Pollock et al., 2010; Antao et al., 2005; Wade et al., 2011; Wang et al., 2013), the root cause is still unknown. Leading hypotheses have focused on the relative amount of rock being cut along with coal in many central Appalachian mines, as there has been a tendency to mine increasingly thinner coal seams over the past couple of decades (Laney et al., 2010; Schatzel, 2009). This shift has likely been accompanied by changes in specific dust exposure factors, such as increased abundance of particularly harmful dust constituents (e.g., silica or silicates) or increased frequency of harmful exposures (e.g., due to work in more risky environments) (Pollock et al., 2010; Blackley et al., 2016; Cohen et al., 2016; Douglas et al., 1986)."

Jan 5, 2018

By Martin H. Col, Thomas W. Steele

The ability to make a good profit in the mining industry is becoming more and more difficult. Typically, grades are lower, sites are more remote, and environmental restrictions are getting tighter than ever before. While the price of the materials P.roduced, such as gold and silver, have stayed flat or declined, the external costs (goods and services) have increased. Increasingly difficult environmental restrictions have increased the lime and costs of develoJ?in9 new deposits, while often placing restrictions on a mme s production rate. Environmental costs for mine closure and site reclamation also make it very difficult to show a long-term profit while mining. Typically, the answer to this cost/price squeeze has been technological innovation. The whole concept of heap leaching low-grade gold ore is one innovation that provided some very goocf profits to the mining companies; but, today, those profits are being eroded by the continuing cost/ price squeeze. This paper will discuss material handling in a heap leach stacking operation and the alternatives of trucks, grasshopper conveY.or systems and mobile conveyor systems.

Jan 1, 1992

By Alan Bauer

In recent years there has been increasing interest in employing the technique of explosive casting in strip mines. Explosive casting, applied to dragline mining, describes the procedure whereby the overburden is horizontally displaced by blasting causing a portion of the material to be thrown into the previously mined cut. Therefore, it is not necessary to subsequently excavate this waste with the stripping equipment. In addition, allowing the overburden unrestricted movement during the blast most often results in improved fragmentation and enhanced machine productivity. The method is receiving attention because the capital and maintenance costs of stripping equipment has risen rapidly in relation to explosives costs. Improved productivity is necessary to maintain unit costs at an acceptable level.

Jan 1, 1983

By L. Alagha, O. Molatlhegi, S. Khatibi

"In the present study, the effect of organic/inorganic (hybrid) polyacrylamide polymer on fine coal flotation was investigated. Raw coal samples contain about 37% of ash-forming mineral at a feed size of -75 + 38 um were subjected to flotation tests in the presence of in-house synthesized hybrid Al(OH)3-PAM at different polymer dosages and pH values. Results show a significant improvement in both combustible recovery and ash rejection at 1 ppm polymer dosage. Further improvement of combustible recovery was obtained when flotation was performed at pH 5. Interfacial properties of coal particles before and after flotation were examined through electrokinetic (zeta potential) measurements of coal/water slurries. Zeta potential vs. pH curve were established and compared. In the case of raw coal/water slurry, zeta potential-pH curve resembles the ash-forming minerals (silica and clays) more than coal. After Al(OH)3-PAM-assisted flotation, the zeta potential of froth/water slurry shifted to more positive values point which strongly indicates significant removal of ash-forming minerals from coal by Al(OH)3-PAM. INTRODUCTION Coal has been a major commodity in meeting the world energy demand during the past several decades (Milici et al., 2013). According to the international energy agency, global coal demand will continue to increase for the coming decades. With increasing world population, the global electricity demand would also increase as more people would get access to basic electricity especially in developing countries (Maggio & Cacciola, 2012). Due to this increase in energy consumption, operations in coal mining and beneficiation processes have been highly mechanized to meet the demands. This mechanization has increased the quantity of raw fine coal particles produced which contain high amount of ash-forming mineral matter (slimes). Aplan et al., have reported that the major constituents of ash-forming minerals in U.S.A coal are clay minerals such as kaolinite, montmorillonite and illite (Aplan, 1997). Conventional froth flotation for fine coal cleaning suffers mainly from two major problems: 1) Low recovery of ultrafine coal particles due to slime coating by ash-forming minerals, and 2) The lack of selectivity, which results in the flotation of middlings and entrainment of mineral fines in the froth (Polat et al., 2003). Slime coating on both valuable and air bubbles have been proposed to explain the observed reduction in flotation recovery especially when fine grinding is required. In this case mineral matter may be degraded to extremely fine or colloidal sizes thereby creating difficulty in the water clarification process such as flotation. Slimes inhibit bubble-particle attachment, and increases reagent consumption due to the increase in solid/liquid interfacial area, resulting in low coal recovery."

Jan 1, 2015

By M. S. Celik

The principal impurities in some feldspar ores are titanium and iron which impart color and in turn degrade the quality of the ore. The mineralogical investigations indicate that titanium element originates from mainly rutile with small amounts of sphene. Conventionally, fatty acids and particularly sodium oleate are extensively used in the flotation of colored minerals from feldspar ores with reasonable success. In this study, new reagents, oleoyl sarcosine and hydroxamate have been used to float colored impurities before and after magnetic separation. Oleoyl sarcosine is found to exhibit better results compared to fatty acids and hydroxamate. The mechanism of the action is elaborated on the basis of experimental data.

Jan 1, 1999

By B. K. Parekh

Large reserves of coal pond fines are found in the Illinois Basin-over 40 million tons in Western Kentucky, over 65 million tons in Southern Illinois, and over 35 million tons in Southern Indiana. If these fines are used to produce coal-water slurry (CWS), fuel costs, NOx. emissions, and pond closure costs can be reduced. Coal fines from this region that are used to produce CWS for co-fire or re-burn may require processing, however, to attain proper particle size distribution and fuel quality. To evaluate the effectiveness of using coal cleaning technologies to control these CWS quality parameters, a simple flowsheet for recovering and processing coal pond fines was designed and tested. Coal fines processing consisted of using classifying cyclones to size at nominal minus 200 mesh, cleaning the classifying cyclone underflow using spirals, and cleaning the overflow using column froth flotation. Ash content of the dean coal from the spiral was reduced to about 10 percent, which is satisfactory to use for CWS co-firing in a cyclone-fired boiler. The clean coal from column flotation may be used for re-burn in a cyclone-fired boiler or as co-fire fuel in a wall-fired or tangentially-fired boiler. Heating value recovery during laboratory-scale, pilot-scale, and commercial-scale coal cleaning testing was about 80 percent.

Jan 1, 1998

By d&apos, L. F. G. Assumpcao

Kaolin samples from Rio Capim resources were treated in conventional and superconducting magnetic separators to study the main variables that influence the color removal process. Coating clays and delaminated clay were tested. Retention time (or pulp injection velocity), magnetic field intensity and matrix type were the' variables studied. The feed brightness ranged from 84.7 to 87.6 % ISO for the coating clays and from 80.7 to 85.4 % ISO for the delaminated clay. The results showed unleached brightness values higher than 88 % ISO for coating products and higher than 87 % ISO for the delaminated product, using a conventional magnetic separator with an applied field of 1.5 to 2.0 Tesla. With a maximum field intensity in the superconducting machine of 5.0 Tesla, unleached brightness values higher than 88.5 % ISO for both coating and delaminated clays were attained.

Jan 1, 1995

By Irving Hauser

The determination of new ways to cut costs in then times of economic uncertainty is essential in running a successful business. Arco Petroleum Products Company a Division of Atlantic Richfield Company recognized an opportunity for a substantial cast savings in transporting calcined petroleum coke to market by simply building an economical port facility at a location that would enable them to drastically cut their normal rail haulage distance.

Jan 1, 1982

By M. S. Klima

Tests were conducted to investigate the potential for recovering anthracite from preparation plant tailings. Samples were collected from tailings streams or slurry ponds of several anthracite cleaning plants. A washability analysis was conducted on each sample. The use of gravity-and surface-based cleaning processes for treating the 28x200 mesh tailings material was examined. Simulations were performed for various cyclone staging arrangements using published partition data for both water-only and dense-medium cyclones. Froth flotation testing was done on both precleaned anthracite and tailings material. Grade-yield curves were determined for various conditions.

Jan 1, 1995