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By Lawrence R. Molsather

Certain hydrologic parameters are affected by development of a mine. These include the area, yield, and storage in a watershed. Alteration of these parameters results in variations in lake levels and stream flow rates and in changes in ground water elevations and gradients. These factors have become increasingly important in light of present environmental design standards and government regulations. Mitigation of adverse hydrologic impacts can be costly and can create operating constraints which complicate the mining process.

Jan 1, 1980

By Firat Atalay

Estimating the spatial distribution of ore grade is one of the most critical steps to proceed with an investment decision on a deposit. Kriging is the most widely used method to estimate the ore grade, but alternative techniques are being developed. Machine learning algorithms can be used as alternative methods to classical kriging. In this paper, the iron (Fe) grade of a deposit is estimated with the XGBoost algorithm, and the results are compared with kriging estimation results. For the estimations, samples collected from drillholes were used. Due to the different natures of the estimation methods, different steps were taken to perform the estimations. The results show that XGBoost produced higher-range estimates, which is a desired result in ore grade estimation, and the minimum and maximum of the estimates were lower and higher than the kriging estimates, respectively. However, like kriging, the estimation results were smoother than composites, and the variance of the XGBoost estimates was lower than the variance of composites. This means that even though estimation with XGBoost mitigates the smoothing effect, the estimation results suffer from smoothing like kriging.

Dec 1, 2024

By F. A. Renninger

The mineral aggregate industry is the world's largest mining and processing endeavor, yet it is graced with little of the romance or public awareness that accompanies mention of gold, silver, iron, copper, uranium, or aluminum mining efforts. Much of this reaction is undoubtedly due to the fact that the uses to which crushed stone and sand and gravel are normally put are not fully recognized or appreciated by the general public. Few individuals ever have occasion to purchase mineral aggregates for anything other than use for decorative shrubbery beds or walkways. They may, however, buy ready-mix concrete for a new patio, bituminous concrete for a new driveway, concrete blocks, or other building materials for a new room and never realize that the primary ingredients of their purchases are either direct or indirect products of the mineral aggregate industry. The average person driving past an operating crushed stone quarry or an active sand and gravel pit rarely realizes the economic impact the industry, represented by that operation, exercises on the general economy. He is not aware, nor does he really care, that elements of the modern comfortable environment to which he has grown accustomed rely to a great extent on the products of the crushed stone and sand and gravel industries Iron and steel, glass, cement, agriculture, and highway and building construction are but a few of the major industries to whom the products of the mineral aggregate industry are basic. Without these industries or without the stone, sand, and gravel basic to them, most of the major elements of our modern day civilization would be non-existent.

Jan 1, 1968

By Suresh P. Babu, Joseph W. Leonard, Richard Muter, D. P. Sen

OUTLOOK FOR COAL UTILIZATION In 1975, about 650 million tons of bituminous coal and lignite mined in the United States was used to meet 55% of the primary energy input for electric power generation and 26% of the total industrial consumption.1 Even though this amounts to only 21% of the total energy requirements, it is believed that with the declining natural gas resources and uncertainty of liquid fuel imports, coal will assume a more dominant role in suppplying our future energy needs. A regional breakdown of the coal reserves of the United States along with their characteristics is shown in Table I. At present the United Stares Energy Research and Development Administration (ERDA) and the US Bureau of Mines (USBM) are financing extensive research programs in advanced mining methods and energy conversion processes. The increased demand for wal which may result from these research programs may also create large-scale environmental protection problems. As more and more coal is mined the production of undesirable coal fines and dust also increases proportionally. The USBM and the Environmental Protection Agency (EPA) research in this field includes development in the areas of instrumentation for qualitative and quantitative analysis of wal dust, protective devices, and dust collectors. Dust control by water sprays, steam, and foam are also being investigated. Other aspects of safety in mining include developing methane drainage techniques prior to coal mining, fire and explosion prevention, and neutralization and disposal of acid mine waters. It is the belief of coal technologists that when the emphasis shifts to coal as the primary source of energy. the existing methods of mining and preparation of coal must be improved considerably to supply large quantities of quality coal for energy conversion. It is the objective of the present large-scale research financed by ERDA to produce substitute fuels from coal. Large-scale gasification pilot plants are being constructed by Bituminous Coal Research, Consolidation Coal Co., Institute of Gas Technology, and the Pittsburgh Energy Research Center to produce coal gas of natural gas standards at 1,000 psig. The processes being adopted by these pilot plants are oriented towards recovering most of the sulfur from coal by absorbing H2S and its subsequent conversion to elemental sulfur. The environmental protection standards will be strictly followed in using the results of these pilot plants to construct large-scale coal gasification plants in the latter part of the 1970's. With the increasing awareness of the need for air pollution control, considerable research is being done to minimize sulfur dioxide emission from thermal power plants. Utilization of limestone and dolomite scrubbing systems and caustic treatment of stack gases have proved to reduce sulfur and nitric oxide emissions by about 90 to 96%.3 Currently, about 22 scrubbers are in use in the United States to reduce sulfur in stack gas emission. In the long-term, it appears that optimal combinations will be developed involving both advanced coal preparation technology and wet scrubbing. The sulfur compounds are converted either to elemental sulfur of sulfuric acid. Besides the sulfur compounds, the major byproduct of the coal utilization industry is the large amount of coal ash. The Coal Research Bureau at West Virginia University has developed a practical use for coal ash as a structural material. The coal industry will undergo revolutionary changes when coal becomes the primary source of energy. New coal mining and preparation processes will be introduced to meet the ever-increasing per capita energy requirements. 2. BENEFICATION Introduction Coal preparation, like the beneficiation of ores, is also aimed at the separation of values from associated waste. Even though the unit operations involved when enriching ores and coal are similar, there are certain characteristics unique to coal preparation. Unlike the scattered and concentrated veins of underground minera1 ores, coal is distributed uniformly and very much in abundance in the coal mines. Coal occurs as the metamorphosed sedimentary deposits of vegetable matter, while metal and mineral deposits occur in great varieties of forms, structures, and origin-from igneous to sedimentary and metamorphic. The mined coal, being much more friable than mineral ores, is subjected to less intensive size reduction operations. Ores are usually ground to a very fine size for subsequent concentration, while coal is crushed to a coarser size, since considerably less liberation is needed to achieve the desired degree of separation. Since mineral matter is to a great extent discretely distributed in coal, concentration is mainly achieved by taking advantage of differences in specific gravity between clean coal and associated waste. In general, about 90% of coal is concentrated using specific gravity separation and about 10% by froth flotation. In contrast, these operations are frequently reversed in the beneficiation of ores. In coal preparation almost all fractions separated during various stages are made use of. while large amounts of gangue material are rejected in the concentration of ores. Hence, coal generally has a much lower ratio of concentration than ores. Since ore deposits are frequently more variable and mineralogically complex than coal, beneficiation of ore may require more plant flexibility and point-to-point quality control. This characteristic difference between the mineral ores and coal is attributed to the generally used one-step processing in coal as compared to the multiple-step processing of ores. Dewatering to enhance the energy content of coal is usually considered a major unit operation. Even though thickening and filtration are common for dewatering ore concentrates and cleaned coal, vibrating centrifuges and disk filters find unique application in the coal industry for achieving these types of solid-fluid separation. In coal preparation, thermal drying is carried out in separate units at the mine. While ore concentrates are usually dried at the smelter. Although the drying of ores is seldom considered dangerous, volatile matter and combustible dust are reasons why the thermal drying of coal can be hazardous. Open air storage of ores and mined coal results in partial oxidation. Unlike the oxidation of ores, the oxidation of the pyritic and carbonaceous constituents of coal together with the heat of condensation of moisture contribute to spontaneous heating and the subsequent combustion of coal in storage. Among the other significant difference between concentration of ores and coal are the weight and capacity of processing equipment. Coal processing employs less cumbersome, higher capacity units while the beneficiation of ores usually requires much more massive and frequently lower capacity equipment. Properties of Coal Which Influence Design The widely varying and heterogeneous composition of coal, due to metamorphism, determines the preparation design and uses of the resulting products. Petrography serves as a useful system of classification to identify the coal types present and their distribution. Early

Jan 1, 1985

By Dragomir Gospodinov, Savka Dineva

A surprisingly large mining-induced seismic event occurred in the LKAB Kiirunavaara Mine (Sweden) on 18 May, 2020 at 03:11 (local time). The estimated moment magnitude was 4.2. The event caused extensive damage in a large section of the mine. The production in the area is not yet resumed, even by the beginning of 2022 (~20 months after the event). The Kiirunavaara Mine has one of the world’s largest underground seismic systems with approximately 253 geophones. The in-mine records of the event showed a very complex character with a several sub-events. The event was also well recorded by seismic stations out to over 9,000 km distance. Data from the underground and regional seismic systems were analysed to define and compare basic source parameters such as hypocenter location, seismic moment, as well as the seismic moment tensor. The data from the in-mine seismic system was used to study the development of the seismic process and to define elementary seismic sub-sources together with the official hypocenter location.

Apr 26, 2022

By S. Upadhyay, A. M. Afrapoli

"Fluctuation in market price of mineral products has enforced mining companies to cut down their operating costs. One useful way of reducing operating costs in mining operations is to make optimal operational decisions, incorporating efficient mining fleet management systems (FMS). Over the last 50 years, several types of FMS have been developed and introduced in the mining systems around the world. However, there are two major shortcomings in existing systems. Firstly, none of the existing systems consider effects of the short-term plan on dynamic truck assignment. Secondly, most of the existing FMSs make decisions in a way that optimize a specific objective while ignoring others. Herein, we propose a multi stage and multi objective FMS that deals with aforementioned shortcomings of the currently available systems. The developed FMS, in its upper stage, links semi-dynamic operational decision making process to the short-term production plan by simultaneously assigning shovels to mining faces and allocating trucks to the shovels by implementing its first multi objective decision making model. Then in its second stage, in a real time dynamic decision making process, it assigns trucks to shovels and corresponding destinations by optimizing its second multi objective decision making model. The developed fleet management system has been verified using an Iron ore case study and the results are presented in this paper. INTRODUCTION Open pit mining method is the most common method to mine mineral from the earth. Based on Wetherelt and van der Wielen (2011) there exist 2500 open pit metal mines that are categorized as industrial scale mines. Over all of those, the amount of material handled using truck and shovel material handling system is more than the amount handled by all other systems together (Humphrey & Wagner, 2011).It has been proven by several studies that more than 50 percent of operating cost in a truck and shovel based open pit mining operation is accounted for material handling (Moradi Afrapoli & Askari-Nasab, 2017, Alarie & Gamache, 2002, Ahangaran et al., 2012). Thus, introducing even 1 to 2 percent cut in its material handling cost saves huge amount of money for the stakeholders. Over the last 50 years, two major areas have been identified to cut this cost. On one hand mining industries have been implementing equipment with higher production capacities, and on the other hand, researchers have been developing operations research techniques to make dynamic decisions as close to optimal as possible to deduct operational costs in truck and shovel based mining operations."

Jan 1, 2018

By Brian F. Osborne

A continuous on-line particle size analysis system for solid/liquid suspensions is described. The basic sensor utilizes a centrifugal principle to separate particles according to size, the resultant separation being measured by means of beta-ray attenuation. Results obtained when analyzing a variety of materials at sizes from 65 mesh (210 microns) to 20 microns are discussed in de- tail. Accuracies better than 2% are demonstrated. The effects of particle specific gravity, and mixtures of materials of diverse specific gravities, are discussed from a practical and theoretical viewpoint. It is demonstrated that particle specific gravity has a minimal effect on the size reading obtained. This renders the instrument suitable for handling materials where the ratio of light to heavy component may change. The design of the first commercial installation of this instrument is described in detail. This installation will be capable of analyzing three streams in sequence, measurement at three particle sizes being effected on each stream.

Jan 1, 1973

By S. J. Schatzel, K. M. Ajayi, E. N. Rubinstein, Z. Khademian

This study simulates the impact of a shale gas well casing breach near a longwall mine. Field studies are conducted to measure mining-induced permeability changes over the abutment pillar of a longwall mine, and a geomechanical model is developed in 3DEC, a three-dimensional numerical modeling code, to predict the aperture of fractures in the overburden at the study site. The predicted aperture values are used to determine mining-induced permeabilities, and the results are compared with the field measurements. These aperture values are provided as inputs into fracture flow code (FFC), which generates a stochastic discrete fracture network (DFN) model for the study site and predicts the potential shale gas flow to the mine. Results from 100 DFN realizations are statistically analyzed using the bootstrapping method to compensate for notable variation in fracture geometry. The results show a significant difference between the gas inflow for nearby panels due to increase in the induced permeability during mining of the second panel. The average gas flow to the mine was calculated as 4.72 × 10 m3/s (49 cfm) for a hypothetical breach at the Sewickley horizon during the first panel mining, 8.97 × 10 m3/s (19 cfm) for a hypothetical breach at the Uniontown horizon during the first panel mining, 2.16 × 10 m3/s (458 cfm) for a hypothetical breach at the Sewickley horizon during the second panel mining, and 8.07 × 10 m3/s (171 cfm) for a hypothetical breach at the Uniontown horizon during the second panel mining. Depending on the mine ventilation system, this could result in methane concentrations exceeding regulatory limits. Hence, these findings provide insights into the potential risk of an unconventional gas well casing breach near a longwall mine under shallow cover.

Feb 1, 2024

By C. M. Brinckerhoff

Much has been written in the mining technical magazines about the caving system. Many of these articles were published in the Transactions of the American Institute of Mining Engineers prior to World War II. In recent years little has been written on mining methods or on the detailed planning always required. Block caving had primarily been used to mine deep copper ores in Africa, the United States and in Chile, although other ores had been mined by this same system. Asbestos ore had been caved in Canada, tin ore in Bolivia, molybdenum ore in Colorado, iron ore in Wyoming and Sweden, and limestone in California.

Jan 1, 1984

By G. H. Schnakenberg

In 1986, the US Bureau of Mines (USBM) embarked on a major research effort to develop technology that could substantially reduce worker exposure to face hazards by simply relocating the equipment operators to an area of relative safety. This reduced-exposure mining system (REMS) research effort enhances the USBM's ongoing health and safety efforts aimed at reducing and controlling dust and noise and reducing accidents through training and better mining practices. This paper reports on the progress made on the developing research and demonstrates the technologies required for the computer-assisted teleremote operation of continuous mining machines, haulage systems and roof bolting machines.

Jan 1, 1997

By Kanchan Mondal, Gopi Bylapudi, Anand Bhagwat, A. J. S. (Sam) Spearing

Corrosion of steel roof support systems can cause potential premature failure of the support, thus adversely affecting the excavation stability and rock-related safety. An in-house corrosion test system was designed and developed to test full-length roof bolts for material performance based on tensile load capacity and strength under different corrosive conditions found underground. Initially, ASTM A615 grade 60 steel roof bolts, which are the most commonly used bolt material in the United States, were tested with and without stresses in a simulated underground coal-mining environment for approximately six months. This paper mainly discusses the test system, protocol and system shortcomings, and makes recommendations based on the observations and results.

By M. Govinda Raj, S. Sridhar, M. Aruna

Hand-transmitted vibration (HTV) exposure is associated with various health risks for operators of mobile mining equipment (MME). The case–control research was conducted to determine the musculoskeletal disorder (MSD) risks associated with exposure to HTVs in the exposed (case) and non-exposed (control) groups. HTV readings were measured at the interface between the hand and the steering device using the SV 105B triaxial hand accelerometer connected to the SV106 human vibration analyzer involving 40 MME operators in accordance with ISO 5349:2001 guidelines. A questionnaire survey was also carried out among both the study groups using Cornell Musculoskeletal Discomfort Questionnaire. The European Union's 2002/44/E.C. was used to assess the health risks posed to the MME operators. Twenty-eight out of the 40 MMEs were generating HTVs exceeding the stipulated daily limits of vibration, putting 70% of the operators at increased risk for developing MSDs. The case group was found to have an elevated risk of exposure with odds ratio (OR) 7.56 (95% confidence interval (CI), 1.159, 49.39) and OR 12.80 (95% CI, 2.436, 67.285) times more likely than the control group to suffer discomfort in the left shoulder and left wrist, respectively, indicating increased risk of exposure to HTV. Additionally, cases had elevated risk associated with exposure to tobacco, OR 9.35(95% CI, 1.856, 47.129) compared to those who did not use tobacco. MSDs were more prevalent in the case group compared to the control group. This observation was validated by the field investigations and the responses of MME operators to the questionnaires.

Aug 2, 2022

By W. S. Weldon

The use of spiral separators for the beneficiation of fine coal typically in the size range -2+0.1mm is now well established process technology. Developments during the mid 1980's resulted in the production of cost effective, efficient large diameter coal spiral separators. Recent developments and research have been geared to optimize metallurgical performance, materials handling and equipment geometry of large diameter coal spiral separators.

Jan 1, 1997

By K. Thomson

The Mule Canyon gold deposit, located 14 miles ESE of Battle Mountain, Nevada, was discovered in 1986 as the result of a GFMC grass-roots exploration program. Drilling to date has identified six discrete orebodies which contain a demonstrated gold reserve of 8.487 million tons at an average grade of 0.136 oz/ton, totaling 1,152,000 ounces. Mineralization is associated with argillic alteration and silicification, localized along NNW trending high-angle faults within Miocene basaltic andesites. Trace element geochemistry at Mule Canyon is typical of upper level hot spring precious metal systems, displaying elevated Ag, As, Sb, Hg, and Se.

Jan 1, 1993

By T. Umadevi, A. Pratap Singh, R. Sah, K. Abhishek

"It was possible to beneficiate a low-grade iron ore fines sample from Bellary-Hospet, Karnataka, India assaying 56% Fe, 9.1% SiO2 and 5.2% Al2O3 and produce two concentrates, namely, a sinter-grade fines concentrate (43.7% by weight), assaying 63.6% Fe, 2.6% SiO2 and 1.7% Al2O3, and a pellet-grade concentrate (30.7% by weight) assaying 64.7% Fe, 2.9% SiO2 and 1.7%Al2O3. Rejects (25.6% by weight) assayed 32.5% Fe, 27.9% SiO2 and 15.4% Al2O3. The mineralogical characterization indicated that the sample consisted of 69.5% ironbearing minerals (56% hematite, 7.5% martite and 6% goethite-limonite), 12.5% quartz and 15.2% clay, and the rest were minor minerals. Liberation size was found to be in the size range of 25 to 100 µm. The process flow sheet consists of jigs, spirals, grinding and low- and high-intensity magnetic separation of the deslimed feed. IntroductionJSW Steel Ltd is a 10-Mt/a integrated steel plant. To produce 10 Mt/a hot metal requires nearly 16 to 20 Mt/a iron ore fines. The fast depletion of highgrade iron ore fines, increased industrial demand and an increase in iron ore prices have necessitated the exploitation and use of low-grade iron ore fines in the steel-making process after beneficiation. Thus, the beneficiation of low-grade iron ores by removing the associated gangue minerals and enhancing their grade is essential. The use of these iron ore fines in sinter and pellet making has prompted the undertaking of systematic studies on low-grade iron ores.Finely disseminated low-grade iron ores with siliceous impurities have been upgraded by gravity, magnetic and flotation-based processes (Burt, 1994; Svoboda, 1987; Houot, 1983). The processing of low-grade Indian hematite ore containing high levels of alumina-bearing minerals as impurities present separation challenges and pose special problems in martite and magnetite, in association with quartz and clay as the gangue-forming minerals. Alumina is mainly contributed by clay (kaolinite, montmorillonite, illite, alunite), lateritic material and gibbsite; some alumina occurs as solids in iron oxide minerals, namely, goethite and limonite. Silica is mainly contributed by quartz and the associated clay. achieving a high-grade concentrate (Pradip, 1994; Singh and Mehrotra, 2007). Hematite ore basically consists of varying amounts of hematite, goethite,"

Jan 1, 2015

By Morley H. Mathewson

The unprecedented demand for capital investment in the mining industry today has intensified management's interest in every known technique which will help to reduce operating costs and increase production. One proven approach leading to the accomplishment of this objective is well known in the mining industry and is gaining added prestige, particularly where keen competitive conditions exist. This approach is in the area of incentives applied to mining productivity. An investigation of many incentive plans now in use throughout the mining industry revealed a predominant number of conventional type plans, Most of these plans are designed to reward the hourly-paid employee on the basis of percent over and above a standard hourly or daily ton rate, By contrast, this search failed to divulge any incentive plan solely and independently developed for production management employees. This does not mean that such plans in the mining industry are nonexistnet, but it does indicate that production management incentive systems are scarce or are being kept under wraps.

Jan 1, 1960

The Mine Safety and Health Administration (MSHA) has conducted studies to evaluate dust control technologies on deep cut continuous mining sections. These surveys have been conducted in different mines using various mining methods, face ventilation systems and dust control systems. The surveys typically consist of respirable dust sampling combined with a time study of mining activities. Measurements of dust control and operational parameters are also made. Critical elements identified for controlling respirable dust in deep cut mining systems include controlling intake dust, dust collector capacity, face ventilation quantities and velocities, positioning of workers, work practices and selection of equipment. This paper discusses how the dust surveys are conducted in deep cut mining sections and how these surveys are used to identify specific dust generating sources.

Jan 1, 1999

By M. Brändström, R. Dube, J. Moyo, T. Perkins, G. Bermudez, L. Bartsch, C. Smith, R. Sorensen

The Kennecott Copperton concentrator is currently the bottleneck for the Kennecott operation and several projects have been initiated to increase throughput. This increase in grinding circuit throughput has resulted in a coarser grind size which has impacted flotation circuit recovery. Metso Outotec 300m3 forced air tank flotation cells are currently utilized in the rougher flotation circuit at the Copperton concentrator. Higher overall recoveries have been observed on the newer Outotec tank cells compared to the original 85m3 self-aspirated flotation cells they replaced. However, coarse particle flotation response on these large, forced air cells did not show encouraging results when compared to smaller previously installed cells. This coarse recovery loss has been attributed to the longer froth transport duration and transport distance on large cells (100m3 and larger). Cell manufacturers addressed the risks of additional coarse particle losses in large cells by installing concentric circumferential launders and crowders (also called center launders). These are designed to reduce froth transport time and distance in the last cells in rougher stages where low residual floatable minerals causes a lack of froth mobility. The center launders also increase froth crowding, which also helps to increase froth transport velocity and increases copper and molybdenum recoveries. A trial set of the center launder retrofits were installed on the last three tank cells in one of the parallel rougher flotation rows at Copperton. The launder retrofits were installed at the end of October 2020 and monitored until March 2021. This six-month trial showed statistically significant improvements in copper and molybdenum flotation recoveries through the rougher circuit.

Mar 2, 2022

By J. Iannicelli

An entirely new level of magnetic filtration technology was put into full commercial production by the kaolin industry of Georgia, U.S.A. during 1973-1974. At present, four kaolin producers in Georgia are operating large magnetic filters each capable of processing over 1000 gallons of kaolin slurry per minute or over 65 tons of kaolin per hour on a dry basis. A fifth large filter will go on stream in August, 1975. Four of these units are 84" machines manufactured by the Pacific Electric Motor Company of Oakland, California. When operated at the maximum 1000 g, p. m. rate, these five large magnetic filters have a combined capacity approximating the entire waterwashed coating and filler kaolin produced in the U.S.

Jan 1, 1976

By I. M. Stewart

In a proposed rulemaking regulating asbestos, nonasbestos varieties of Tremolite, Anthophyllite and Actinolite would be excluded from the regulations controlling permissible exposure to asbestos fibers. This proposed rulemaking is perceived as improving the scientific basis of the regulation of asbestos because it recognizes that there are no scientific data, either mineralogical or health related, which support the regulation of nonasbestos Tremoiite, Anthophyllite and Actinolite in the same manner as asbestos fibers. However, the proposed regulation, while representing a major advance in the treatment of AT A for regulatory purposes, does not provide an adequate analytical method for distinguishing between asbestos and nonasbestos particles, nor an adequate description of the regulated minerals. This paper addresses those topics, recommending that OSHA include an appropriate mineralogical definition, and implement a discriminate counting procedure to distinguish asbestos from nonasbestos particles.

Jan 1, 1992