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By Guangyao Si, Ismet Canbulat, Xun Luo, Yi Duan

Routine analyses of seismicity and event locations are essential for coal burst risk management, especially in the presence of unfavorable and complex geology. In an Australian longwall coal mine, a small-scale seismic monitoring network was installed to monitor a section of a major dyke intersected by the roadway, which was classified as a coal burst prone zone. The Deep Convolutional Neural Network (DCNN) technique was adopted for automatically discriminating seismic events to assess seismicity in this zone. The discriminated seismic events were located with the Shortest Path Method based on the Boundary Discretization Scheme (BDS-SPM) for temporal-spatial seismic event distribution analysis. The results demonstrate that the seismic events are discriminated with an average accuracy of 94%. Moreover, the seismic events are more accurately located using the BDS-SPM with a 3D heterogeneous velocity model compared with results obtained with a homogeneous velocity model. The temporal and spatial variances in seismic activities identify that the rock fractures in the dyke zone are closely related to the longwall mining process and a local dyke has a controlling influence on the stress concentration in its vicinity.

Apr 26, 2022

By J. Jorge, J. Mariño-Salguero, B. Álvarez-Rodriguez, J. M. Menéndez-Aguado, J. J. de Felipe

"This work focuses on the characterization of heat generation during dry fracture by direct impact of a tantalum ore. Moreover, an attempt was made to quantify the heat energy loss to the environment during the grinding process of a ball mill. The study was carried out using mineral samples from a Spanish mine that were characterized by measuring their density and specific heat. During the experiments, increases of temperature ranging from 5.9 to 7.3 °C after the fracturing process were observed. A numerical model was then applied to calculate temperature distributions through the mill wall. Three possible combinations of heat transfer coefficients were analyzed, from (1) Kapakyulu and Moys, (2) Duda and (3) the heat transfer laboratory of Universitat Politècnica de Catalunya. The models with the coefficients from Kapakyulu and Moys and the heat transfer laboratory of Universitat Politècnica de Catalunya were found to provide results that were in best agreement with the experimental data. IntroductionEvery year, several billion tons of metallic ores, minerals, cement and other solids used in the ceramic and chemical industries are subjected to size reduction in ball mills around the world. The U.S. Department of Energy (2005) reported that in the United States about 29 percent of the total energy used by the mining industry, or 0.4 percent of total U.S. energy consumption, is used in comminution. In Canada and Australia, comminution is responsible for about 2 percent and 1.5 percent of total energy use, respectively. In nonindustrialized countries where mining constitutes higher fractions of their industrial sectors, comminution costs represent a significant contribution to mine operating costs. The specific energy consumption values for the grinding of these materials typically range from 5 to 50 kWh/t. Thus, a significant amount of electrical energy is consumed in the ball mill grinding operation (Aguado et al., 2006; Gupta and Sharma, 2014). Grinding can represent up to 50 percent of the direct operating cost in a mineral processing plant, especially as comminution devices operate in highly inefficient ranges of 4 to 8 percent (Wang, Yang and Yu, 2012)."

Jan 1, 2017

By R. C. Burtan

Long before the dawn of recorded history, man began to dig into the earth's crust in a never ending search for useful materials. It has been well established that prehistoric man discovered flint. "The Flintstones" were aptly named. The flintknappers of southern England and Wales still exist today in ever dwindling numbers as they seek out chunks of flint. It is a well known fact that more than half of the earth's crust is composed of silicon dioxide (SiO2), also known as silica. Silica and silica containing materials have a great many uses in modern society. However, this material is potentially extremely hazardous to our health. Centuries before the Christian Era, Hippocrates wrote of a lung disease common to those who mined in hard rock. It is obvious to us that he was describing silicosis. It is also apparent from ancient writings, that the Egyptians were aware of this malady. Dioscorides also wrote on this subject in the fifth century, B.C. It is undoubtedly the oldest and best studied of the occupational lung diseases. It was certainly described by Agricola in his "De Re Metallica" published in 1556, in which he described lung disease among hard rock miners. This publication, I'm sure, is of special interest and perhaps known to many of you in the mining community. The original document was written in Latin and was translated in 1912 by two gentlemen, Hoover and Hoover. One of these translators was Herbert L. Hoover, a former president of the United States, who made his living before his presidency as a mining engineer.

Jan 1, 1984

By Leonard Sugin

As we approach the end-of the 20th century we are made more aware of the tremendous role that energy plays both directly and indirectly in our varied way of life. The industralized nations of the world have already established industries and economies which are greatly dependent upon the availability of energy. The underdeveloped and developing nations of the world are slowly and surely moving to the same utlimate requirements. The world wide need for distribution of energy sources is continuing to grow. At the present time there is a great imbalance between the sources of energy and the consuming economies In order to bring about greater equality between supply and demand major efforts and large capital expenditures are constantly being made. Industralized areas are seeking their own independent sources of energy whereas those areas of the world which contain great reserves of energy are limiting its export as well as developing its own industralized capacity. Nevertheless, energy bearing materials are still transported great distances in order to satiate the appetites of power hungry economies.

Jan 1, 1975

By Xin Wang, He Shao, Wenpu Li, Yiyi Zheng, Xi Chen, Yurong Gao

This study utilized experimental and numerical simulation methods to investigate and analyze the atomization characteristics of three internal air–water mixed atomizers under different operating conditions. By comparing the research results, the effective dust control working parameters for the application of the selected atomizer in the engineering field were determined. Firstly, the atomization characteristics of the three atomizers were studied using a customized experimental system. The results indicated that nozzle 2 had a wide atomization range, a small atomization distance, and small droplet size; nozzle 3 had a narrow atomization range, large droplet size, and fast atomization speed; and nozzle 1 not only had a large atomization range but also could produce droplets of dry mist size with fast atomization speed, meeting the dust reduction requirements of the Majiliang Coal Preparation Plant. Secondly, Fluent software was used to simulate the atomization process and particle size distribution of the three internal mixed atomizers, determining the working conditions of the atomizers, the required number of atomizers, and the application angle of the atomizers in the internal mixed dust removal system. Finally, the atomized dust control system was applied on-site, achieving a total dust removal efficiency of 90.72% and a respirable dust removal efficiency of 89.75%.

Mar 9, 2024

By M. F. Vancas

The San Manuel oxide ore reserve ranges in depth from being exposed on the surface to lying 1000 ft. beneath a conglomerate layer all of which is confined in the subsidence zone of an active sulfide block caving operation. Present day recovery of the oxide copper values is either by open pit mining-dump leaching, or in-situ leaching of the oxide ore using dilute sulfuric acid solutions and solvent extraction/electrowinning processing of the pregnant leach solutions. Future plans are for continuation of leaching with expansion of reserves and increased processing rates. The state of the mining industry and copper in particular has not been good for a number of years. All of the producers that are still operating have made major adjustments in order to remain competitive. Magma Copper Co. is no exception.

Jan 1, 1987

By V. T. McLemore

"Production of industrial minerals remains important to the rural economy of New Mexico. In 2014, some 240 mines were registered in New Mexico, including 25 industrial mineral operations and 189 aggregate operations. New Mexico leads domestic production of potash, perlite, zeolite, and travertine. Other production includes aggregate, humate, pumice, gypsum, salt, common and fire clay, scoria, limestone, fly ash, cement, magnetite, silica, and decorative stone. New Mexico has potential for additional production of industrial minerals. One company is exploring for garnet. Cretaceous black sandstones in the San Juan Basin have drawn interest for titanium, rare earth elements (REE), and zircon. Other REE deposits are being explored. REE-Th-U veins are found in the Gallinas, Capitan, and Cornudas Mountains and Laughlin Peak-Chico Hills. Recent exploration has occurred for beryllium in the San Mateo Mountains, Iron Mountain, and Victorio districts. Companies also are examining High-Ca limestone and High-Mg dolomite for potential development. Aggregate continues to be important in urban areas and along highways. INTRODUCTION Industrial minerals and rocks are literally the building blocks of our way of life and they are an exceptionally diverse and vital group of raw materials that underpin almost all aspects of human activity, infrastructure, and standard of living. Industrial minerals and rocks are used in the manufacture of many products, from ceramics to plastics and refractories to paper. Although industrial minerals permeate every aspect of daily life, their presence and their role are typically invisible. A widely used definition of industrial minerals and rocks is “any rock, mineral, or other naturally occurring substance of economic value, exclusive of metal ores, mineral fuels, and gemstones: one of the non-metallics” (Bates, 1975). This definition includes the important construction materials sector as well as specialized industrial minerals, but complex interactions between consumer industries produce a number of apparent anomalies to this definition. Some metals are included as industrial minerals because their use is industrial rather than as a metal. Sulfur is now predominantly extracted as a by-product of cleaning natural gas, one of the world's major energy fuels. Production of industrial minerals has been and remains important to the rural economy of New Mexico. Industrial minerals constitute nearly 40% of the more than $2.8 billion generated by mineral production in New Mexico in 2013 (Table 1, see APPENDIX). In 2015, some 240 mines were registered in New Mexico. This total includes 25 industrial mineral operations and 189 aggregate operations. New Mexico leads domestic production in potash, perlite, zeolite, and travertine. Other industrial minerals production from New Mexico includes aggregate, humate, pumice, gypsum, salt, common and fire clay, scoria, limestone, fly ash, cement, magnetite, silica, and decorative stone. Additional production statistics are in Harben et al. (2008). Major industrial mineral districts are shown in Figure 1."

Jan 1, 2016

By C. B. Manula

The Crushed Stone Industry plays an important role in Pennsylvania's mineral economy. During 1965, the total production of crushed and broken stone in the United States reached 780 million tons from which 57 million tons were produced in Pennsylvania (Mineral Industries Surveys, 1966). It is further significant that Pennsylvania is the nation's leading crushed stone producer. Future trends in stone production will quite likely parallel those in the construction industry. Stone and stone products are finding greater and more varied uses each year. Continued record expenditures for structures such as dams, highways and buildings are the prime reasons for this accelerated growth in demand. Completion of the interstate road system and the maintenance of Pennsylvania's already expanded highway system form the essentials for this expanding market.

Jan 1, 1968

By Robert C. Pease

Siskon Gold has started gold production at the San Juan deposit in northern California. The mine is located about 27 km (17 miles) north of Nevada City, CA (Fig. 1). It is scheduled to be-come the largest underground gold mine in California. It is situated in the western foothills of the Sierra Nevada Mountains in the Mother Lode gold belt. The property consists of 8 km2 (2,000 acres) of patented land. It is situated in a topographically high area known as San Juan Ridge, which is 213 m (700 ft) above and between the Middle Yuba and South Yuba rivers. The elevation is between 790 and 914 m (2,600 and 3,000ft) above sea level. Annual precipitation averages 1,346mm (53 in.). Most of that falls between November and April.

Jan 1, 1996

By L. S. Fountain

A national survey, 1978-1980, found 180,973 waste impoundments used by industrial mining, municipal and other interests. Possibly 27,000 contain hazardous materials. The potential hazard of leaks polluting water supplies is a growing concern. An electrical technique was developed to efficiently and speedily detect and locate leaks in geomembrane-lined liquid impoundments without emptying the contents. A potential applied between the liquid and earth causes electric current to flow through leaks in the insulating geomembrane material to ground. The cur- rent density around the leak is used to detect and locate the leak. Field tests show single and multiple leaks 2.54 cm in diameter or less can be detected and located to within less than 30 cm.

Jan 1, 1986

By Richard E. Lounsbury

Coal mine refuse handling traditionally has been the redheaded stepchild of the industry - a problem to be ignored as much as possible. During the past few years, however, mining companies have become more aware of the potential water pollution problem associated with refuse handling and storage. Planning for refuse disposal increasingly emphasizes protection of the environment as well as economics of refuse handling. Coal companies are responding to the environmental control needs by devising new systems and adapting well-known techniques to refuse handling systems. Monterey Coal Company has operated a non-polluting refuse disposal system at its No. 1 Mine for over two years. The purpose of this paper is to describe the design considerations given to the planning of that system and the operational experience gained during its construction

Jan 1, 1973

By W. J. Guay

Carbonaceous gold ores containing gold dispersed in sulfides are refractory to cyanidation because: ( 1) the carbonaceous materials adsorb gold during cyanidation; (2) a portion of the gold is so finely dispersed in the sulfide mineral lattice as to preclude contact with cyanide solution; and (3) a portion of the gold is chemically combined with carbonaceous material. Techniques which have been used to treat these ores are: (1) roasting or chemical oxidation to decompose sulfides and carbonaceous materials; (2) flotation to reject carbon; (3) the use of kerosene or other reagents to passivate the adsorptive carbon compounds; (4) carbon or resin in pulp; (5) flotation of a bulk concentrate which is treated by one of the above methods; and (6) the use of chelating agents which have a stronger affinity for gold than the activated carbon in the ore.

Jan 1, 1981

By Norman F. Schulz

The technical excellence of separation achieved in a mineral concentration process, or any other process where two constituents of any kind are physically separated from each other, is expressed uniquely and quantitatively by the Separation Efficiency: ES = (R ? Rg) where R is the percentage of the valuable constituent and Rg the percentage of the waste appearing in the concentrate. The Separation Efficiency meets all the usual requirements of a true efficiency and is independent of the nature of the process used. It can be visualized as the percentage of the feed material that, in effect, actually undergoes complete separation while the rest of the feed is distributed randomly and unchanged into the two separation products.

Jan 1, 1969

By Z. Jin, D. DePaoli, P. Zhang

"Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P2O5 ), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C, REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P2O5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 µm, was separated from leached phosphogypsum through elutriation, in which the P2O5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum. IntroductionPhosphogypsum is a byproduct generated during the industrial wet process of phosphoric acid production, in which sulfuric acid is used to digest phosphate rock. Gypsum (CaSO4·2H2O), the main component of phosphogypsum, usually accounts for 65 to 95 percent of phosphogypsum by weight.There are small quantities of impurities in phosphogypsum, such as phosphates (H3PO4, Ca(H2PO4)2·H2O, CaHPO4·2H2O and Ca3(PO4)2), fluorides (NaF, Na2SiF6, Na3AlF6, Na3FeF6 and CaF), sulfates, trace metals and radioactive elements (Rutherford, Dudas and Arocena, 1996). Global phosphogypsum generation is estimated at 200 Mt/a (Parreira, Kobayashi and Silvestre, 2003; Yang et al., 2009), but only about 15 percent is recycled as building materials, agricultural fertilizers or soil stabilization amendments (Tayibi Choura and Lopez, 2009)."

Jan 1, 2017

By Robert J. Garino

Around two-thirds of world silver mine production comes from mines where the majority of ex-mill revenue is obtained from other metals. In this talk I will illustrate the importance of this output of silver as a by-product of the mining of various base metals. I will also consider the impact of relative changes in base and precious metal prices on mill-head revenue, and therefore, on production decisions. During the latter half of 1982 improving silver prices encouraged re-openings at several base metal mines. Thus some production of lead, zinc and copper can be regarded as partly conditional on the prevailing silver price. Conversely, a good deal of silver production can be considered to be independent of the silver price and dependent on the production of some base metal. It is the degree to which the value of silver mined affects the revenues of nominally, base metal, producers that is the central concern of this presentation.

Jan 1, 1983

By S. M. Hsiung

Chain pillar design formula under weak roof condition was developed by statistically analyzing the results from the three dimensional finite element parametric analyses. The parameters such as mechanical properties of the roof and floor strata, overburden depth, panel width and length, and coal strength were incorporated in the formula. A conversion formula which transfers a rectangular chain pillar into a square chain pillar of equal strength is proposed. The influence of high in-situ horizontal stresses, which are often encountered in the coalfield, on chain pillar stability is also discussed.

Jan 1, 1984

By J. A. G. Llerena, J. Sattarvand

Tailings dam failures have been occurring in recent years. They are considered more vulnerable than hydraulic dams due to the lack of regulations on specific design criteria, and stability requirements regarding monitoring during the construction and maintenance process. Thus, monitoring the dam is essential to know the dam's existing state and ensure its safety. One of the reasons tailings storage facilities fail is slope instability caused by moisture content. A relationship does exist between moisture content and surface strength, early detection of seepage would help to assess the physical condition of the dam. Moreover, to cover the tailings dam area in an efficient way Unmanned Aerial Vehicles (UAVs) are suitable because of their versatility and high-resolution data acquisition. Mounted with a high-resolution RGB camera, and thermal, or hyperspectral sensors UAVs can acquire good quality images that combined with image analysis and machine learning algorithms yield a good estimate of soil moisture.

Feb 1, 2023

By S. Veeramasuneni, Qingxia Liu, Susan Dichter

Gypsum (CaSO4-2H2O) is an abundant and naturally occurring mineral. Under elevated temperatures (250 to 300°F) gypsum loses its crystalline water and is converted to hemihydrate (CaSO4 -0.5H2O). The hemihydrate form is also called plaster that is widely used in wall- board, joint compound, and many other industrial applications. At temperatures higher than 450°F (up to 1,200°F), gypsum loses all crystalline water and is converted to anhydrite form (CaSO4). The loss of crystalline water at elevated temperatures is an endothermic reaction. This property makes gypsum an attractive filler and fire retardant in certain thermosetting plastics. The applications of gypsum in plastics, food, pharmaceutical, and paper coatings will be reviewed in this paper. The future of synthetic gypsum, a by product of various industrial processes, will also be discussed.

Jan 1, 2003

By Robert B. Scott

The Dents Run Demonstration Project near Morgantown, West Virginia, was a cooperative venture involving the U.S. Environmental Protection Agency (EPA), the Water Resources Division (WRD)(1) of the West Virginia Department of Natural Resources (DNR), and the Christopher Division of the Consolidation Coal Company (CONSOL). The object of this project was to demonstrate pollution control methods and to clean up a 37.8 sq km (14.6 sq mi) watershed severely polluted by coal mine drainage. A study entitled, "Water Infiltration Control to Achieve Mine Water Pollution Control" (EPA-R-2-73-142),(2) was conducted by the Cyrus Wm. Rico Division of NUS Corporation for the grantee to determine the feasibility of utilizing remedial techniques to improve the Dents Run water¬shed. This study showed that the Dents Run watershed was discharging as much as 6,870 kg/day (15,100 lb/day) of acid; 1620 kg/day (3,560 lb/day) of iron 17,250 kg/day (38,000 lb/day) of sulfates; and 29,500 kg/day (64,900 lb/day) of total dissolved solids into the Monongahela River near Morgantown, West Virginia. This pollution was caused by the combination of borehole pump discharges from active underground mines, runoff from abandoned strip mines, and runoff from refuse dumps.

Jan 1, 1977

By A.M. Wala

A new radioactive tracer method to measure airflow in inaccessible airways has been developed for situations when studies of the mine ventilation system are not possible using conventional flowmeters (anemometers). The new method has been tested in the ventilation laboratory at the University of Kentucky and in the Experimental Underground Coal Mine at the U.S. Bureau of Mines. This new tracer method has been utilized in leakage, dilution and flow velocity measurements in laboratory and field (mine) experiments.

Jan 1, 1996