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By Wladyslaw John Cieslewicz

Geologically, this region is occupied by Mesozoids, a folded belt of Triassic and Jurassic sediments and volcanics. Gold mineralization is of Upper Jurassic age. Most of the stream placers formed during the Quaternary. Placer gold was first discovered in 1916. Between 1930 and 1957, mining was carried out by the "Dal'stroi," a Russian death- camp organization. At the mines, "Dal 'stroi" exterminated 5-7 million captives taken from Russia's different colonies, each prisoner extracting 1-2 kg of gold before he died. Since 1966 the mines have been worked mechanically. About 10 mining districts are now active, producing altogether 110-135 tons of gold annually.

Jan 1, 1987

By A. Noble

"A supply of sustainably sourced rare earth elements (REEs) is critical for several high-tech industries, renewable energy technologies, and defense applications. Recent studies have shown that REEs exist in coal and coal combustion byproducts at elevated concentrations and in quantities that could meet domestic demand. Despite these promising findings, declines in rare earth prices, volatile commodity markets, and challenging geo-metallurgical conditions have jeopardized this potentially valuable REE resource. While the dilute REE concentrations inherently necessitate low-cost separation technologies, the ultimately operating cost threshold for economic extraction must be based on commodity price projections and market demand. In this paper, the micro-pricing principle is used to develop a rigorous economic model assessing the inherent value of REEs in coal materials. This model is based upon basket pricing of individual elemental oxides, and elemental distributions of coal samples from various basins. These results may be used to assess the economic viability of potential REE concentration and refining technologies INTRODUCTION Recent efforts by US Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) have suggested that rare earth elements (REEs) may exist in coal and coal byproducts at concentrations suitable for economic extraction and processing. While the knowledge of REE occurrence in coal material dates back over 50 years, recent supply restrictions and material criticality considerations have prompted a national interest to establish a sustainable domestic supply of REEs. REEs are not “rare” in the sense of crustal abundance; however, few natural processes lead to concentrated ore deposits. As a result, the elevated concentrations found in coal material may provide a potentially promising resource for these materials. While the term “rare earths” is often used to describe a singular concept, the 15 rare earth elements actually have varying and sometimes contrasting scarcity and cost profiles. Various authors have proposed classification systems to provide information on REE criticality (e.g. Seredin and Dai, 2012, Zhang et al., 2015). The most straightforward classification is provided on the basis of geochemistry with designations for “light”, “medium” and “heavy” rare earths. Light rare earths (those to the left of the periodic table: Ce, Pr, Nd, and Sm) tend to be more common and less valuable when compared to their medium (Eu, Gd, Tb, Dy, and Y) and heavy (Ho, Er, Tm, Yb, and Lu) counterparts. While light rare earths are often found in traditional ore deposits at economic concentrations, the heavier rare earths are almost exclusively found as ion-absorbed clays (Seredin and Dai, 2012)."

Jan 1, 2016

By Don Painter, Nico Sutmoller, Lori M. K. Kahikina, Brian Dorwart

This paper will address the feasibility of using low-density cellular concrete (LDCC) for an annular fill application where project conditions required pumping the LDCC material for distances of up to 16,000 feet. These conditions occurred during construction of the Kaneohe-Kailua Sewer Tunnel in Oahu, Hawaii, between 2014 and 2018. Located on the island of Oahu, Hawaii, this 13-foot-diameter rock tunnel extends for approximately three miles from the Kaneohe Pre-Treatment Facility to the Kailua Regional Wastewater Treatment Plant. The tunnel was built to convey wastewater and provide temporary storage for peak wet weather flows entering the collection system, thereby reducing the potential for uncontrolled discharges. LDCC was chosen for this project partly due to its environmental benefits, which were essential for an application contiguous to the inland marine and coastal waters of the Pacific Ocean. In order to ensure optimal performance characteristics—compressive strength (with a requirement of 300 psi at 56 days), flowability, and light weight—were achieved, extensive testing of various LDCC products and mix designs was completed. The testing measured the initial set time of the LDCC as well as the compressive strength needed to reduce the quantity of grout lifts required for the project.

Jun 13, 2021

By William M. Gray

[The products of mites hive historically beet a very large and important segment of total shipment transported by American Railroads. Much as the Mining transportation Executives right have wished for coal and other mineral deposits to be found along navigable rivers, where railroads have for years been competing with the very aggressive Army Corps of Engineers and the inland waterway operators, the mineable reserves are more often that not located in the arid west far from these "free" waterways. The rivers cannot go to the mines but the railroads could, did, and continue to invest it new lines to reach new mines. The mining industry and the railroad industry have good reason to rely upon each other. The former Northern Pacific Railway, the Great Northern Railway, the Chicago, Burlington and Quincy Railroad and the Spokane, Portland and Seattle Railway merged in 1970 to form the Burlington Northern Railroad, with Lou Menk as its first President. As unofficial spokesman for the industry, be had, for years, conducted a tireless effort to educate shippers, lawmakers and the general public of the single most critical problem confronting the railroad industry, the strangle bold of government regulator.]

Jan 1, 1985

Caterpillar recently held two, two-day demonstration programs for its mining customers. The event, billed as MineDemo by Caterpillar, consisted of two sessions held on consecutive weeks at the company's Tinaja Hills proving ground south of Tucson, AZ. The program included several classroom sessions that focused on Caterpillar equipment applications, including the VIMS (vital information management system) and the CAES (computer-aided earthmoving system). Also included were field demonstrations and the opportunity to test drive mining-related heavy equipment, including dozers, trucks, graders, shovels and loaders. Featured at the event were the recently upgraded 785, 789 and 793 C-Series trucks. Caterpillar recently announced the availability of the 136-t (150-st) 785C and the 177-t (195-st) 789C. The upgraded haulers have replaced the respective B-Series models. The 218-t (240-st) 793C was introduced in 1996. It, too, has been upgraded but retains the C-Series designation. While attending the press event, the author had the opportunity to test drive the 793C at the Tinaja Hills test site. It was amazing how well the machine handled. The operation was smooth and the braking system was precise. The cab was extremely comfortable. To see a C-Series truck in action, the author also visited Newmont Mining's Mesquite Mine, located in Cali¬fornia, across the border from Yuma, AZ. The Mesquite Mine operates a new model 785C truck. At the mine, temperatures have been measured as high as 58° C (138° F) in the pit. Needless to say, the ability to operate dependably in extreme heat is an important consideration for the mine operators. An interview with the driver and later with management confirmed that the 785C has worked out well. The driver praised the comfort of the cab and the ease of operation. Management reported significant fuel savings and was impressed by the truck's maintenance features.

Jan 1, 1999

By S. D. Irons

With the passage of recent national and state legislation aimed at tighter regulation of air pollution and smoke control, attention has been focused on a problem which has long confronted the coal industry--the disposal of coal waste with its inadvertent ignition. Even as recent as 1935, a decision from the Allegheny County Court of Common Pleas confirms the stand taken on control of burning coal refuse disposal areas. "The uncontroverted testimony is that there is no feasible method of operating a coal mine without a gob pile on the surface, as no use has ever been found for this troublesome by-product of mining; that every large coal mine has a large gob pile close to its tipple; that sooner or later these piles all ignite through spontaneous combustion; that practically every large mine in Western Pennsylvania has a burning gob pile, and that there is no known means of averting such a fire." 19* As a result of the past "no regulation policy," there are presently on the order of 500 burning refuse banks, of which 213, 142, and 49 are found in West Virginia, Pennsylvania, and Kentucky, respective¬ly. 18 Many of these refuse banks have burned for 40 years or more; many others may continue burning for a like period. It is estimated that the annual emission from these smoldering piles approaches 183,000 tons of pollutents which may produce many deleterious effects on the populace, property and vegetation in the proximity to the sources.16 To date, little progress has been made in alleviating the pollution from the currently burning refuse banks; however, numerous investigators who are researching the causes of ignition, as well as preventative disposal techniques (refuse compaction, layering and crushing to finer sizes) have met with some success in handling the newly discarded coal refuse.

Jan 1, 1967

By A. A. Terchick

It has been reported in the literature that there is a substantial economic incentive for removing sulfur from coal. Therefore, U. s. Steel initiated an investigation to determine the feasibility of lowering the sulfur content of its Pittsburgh-seam coal. Preliminary crushing and washability studies on a representa-tive sample indicated that substantial sulfur reductions could be attained. Figure 1 shows the effect of the top size of a given coal sample on the sulfur content of the float-l.45 specific-gravity fraction of coal. At a top size of 3 inches, the raw-coal sulfur content of 2.32 percent was reduced to 1.64 percent. Crushing to a top size of 20 mesh reduced the raw-coal sulfur to 1.25 percent. Below a top size of one inch, the sulfur content decreased rapidly as top size was decreased. Figure 2 shows the effect of specific gravity of separation on pyritic sulfur. Normally this coal has an organic-sulfur content of approximately 1 percent. As expected, pyritic sulfur was reduced as the separating gravity was lowered for all the various size fractions shown. The rate of decrease in pyritic sulfur was gradual above 1.45 specific gravity, but great below 1.45. Greater sulfur reductions were attained on the coarser sizes with decreasing

Jan 1, 1971

By Murat Erdemoğlu, Turan Uysal, Thierno Saidou Barry, Mustafa Birinci

The rapid development of the global alumina and aluminum industry is straight coupled with the demands and the needs of these materials. Nowadays, the only well-known accessible resources to produce alumina and aluminum are bauxite ores. But bauxite ores are limited, and the remaining exploitable reserves do not have high contents in alumina. In countries where there is little or no bauxite reserves or where the recovery of existing bauxite ores to produce alumina with the Bayer process are not economic, alternative resources for alumina have been explored. The most attractive resources for replacing bauxites are aluminosilicate clay minerals and coal fly ash. The important processes developed for the recovery of alumina from these sources are acid leaching and alkaline leaching processes. The acid leaching is known as the most efficient in which thermal and mechanical activation are included for improving the performance of the process. The objective of this review is to give a comprehensive insight on the production of the alumina from thermally or mechanically activated clays and coal fly ash by hydrochloric, sulfuric, and nitric acid leaching processes.

By Pratama Mochamad Rizki, Andika Satya

High-risk area in open-pit mining should always be monitored by the operational supervisor because of its nature. One of this type is the soft soil dump area. Due to the unstable bearing capacity of the soil, it’s highly possible for us to find cracks in the area. This paper aims to build computer vision which able to detect truck’s distance from safe limit allowed during dumping activity. The system will warn the truck’s driver if the truck has crossed that predetermined safe limit.

Jun 25, 2023

By G. A. Kordosky

Solution mining followed by solvent extraction-electrowinning (SX-EW) is one possible way to economically extract copper from ore bodies which cannot otherwise be profitably exploited. Published costs for the unit processes of SX and EW are out of date especially in view of the newer reagents now available and the newer circuit configurations, This paper updates the costs for SX-EW in 1985 dollars and also discusses some of the trade-offs which must be made when designing an SX-W plant.

Jan 1, 1986

By Hongling Wang, DI WU, Shuai Li, Hui Shu

Isothermal reduction experiments on carbon-bearing pellets of copper slag were investigated by the thermogravimetric method with biomass carbon as a reducing agent. The results indicated that the reduction process of copper slag‑biomass composite pellets was dominated by gas phase diffusion, and the apparent activation energy was 88.44 kJ/mol. In the temperature range from 1000 to 1200 °C, the metallization rate of pellets increased with increasing temperature, and the maximum metallization rate was 78.4%. The optimal reduction temperature of CSBCP (copper slag-biomass composite pellets) was 1200 °C.

Nov 23, 2022

By T. Kawashima

The expanding volume of maritime coal transportation is intensifying the problems concerning large vessel service port construction, transshipment and environmental control. The major problem is the transshipment of coal. Customary methods for bulk transfer must be improved and/or new systems developed. Slurry unloading has a key role in the new systems. The present report reviews progress in slurry transportation research which has been done in Japan since the 1960s when large scale experiments for domestic transportation were done. Experiments on the effects of vibration on the slurry cargo and on reslurrying are discussed.

Jan 1, 1982

By J. R. Hoskins

Method - A direct approach to instrument users, initially by letter and later by telephone or personal contact was made. The resultant data was compiled to give specific use information on the seven instruments. During the course of the study attempts to evaluate the Griswold Gage were abandoned when it became apparent that the gage was not being commercially produced. One company is developing the gage for its own use. The information presented is the result of over 1200 inquiries.

Jan 1, 1973

By W. G. Pariseau

A study of coal pillar strength at the Beehive Mine in central Utah was done in the 1970s. This study was a cooperative effort by the University of Utah, RE/SPEC, Inc., and the American Coal Company and was funded by the U.S. Bureau of Mines. Mine measurements of closure at 117 points and pillar stress using 119 vibrating wire stress gauges were made during retreat mining in this room-and-pillar operation. Laboratory testing for the strength and modulus of 372 coal cylinders up 0.3 m (1 ft) in diameter and 0.6 m (2 ft) in length was also done. Two-dimensional finite element model analyses complemented the study. However, the real world of mining is three-dimensional and in consideration of the significant advances in computing power since the time of the original study, a revisit of the data seemed warranted. In this regard, a novel finite element method was used that allows for the whole-mine analysis of tabular excavations on the kilometer scale and yet enables details to be obtained at pillar walls on the meter scale. The effects of material properties variability in situ and of joints can also be taken into account. Results that compare computed two- and three-dimensional seam-level closures with mine measurements show noticeable differences; three-dimensional results are reasonable, while two-dimensional results overestimate closure by nearly a factor of two.

Jan 1, 2014

By C. K. Arthur, N. K. Dumakor-Dupey, B. A. Kansake, F. A. Kaba

Autonomous mining systems have been deployed for improving mine performance. However, there is a fear of job losses. Adoption of autonomous systems is envisaged to be resisted by major stakeholders in Ghana due to high illiteracy and unemployment. This paper assesses the preparedness of Ghanaian mining stakeholders for the adoption of autonomous systems to Ghana’s surface mining industry. Closed and open-ended questionnaires were administered to mine stakeholders. Respondents generally expressed unwillingness to accept autonomous systems into Ghanaian mines due to fear of increased unemployment. We propose setting up a mining education fund (MEF) for training stakeholders in autonomous mining systems. INTRODUCTION Mining contributes enormously to the sustenance and growth of global and national economies through the provision of raw materials, employment, revenues and foreign exchange (Carvalho, 2017; ICMM, 2017; Cordes et al., 2016; Solomon et al., 2008; Walser, 2000). The International Council on Mining & Metals (ICMM, 2014) reported that globally, formal mining employs approximately 2.5 million people. Many resource-rich countries, especially the developing ones, have experienced strong socioeconomic growth propelled by the discovery and extraction of valuable minerals. McMahon and Moreira (2014) reported a positive linkage between mining and sustainable development. They revealed that averagely, resource-rich countries have improved Human Development Index (HDI) scores than countries without mineral resources. Mining remains a crucial industry in Ghana’s economic development (Bermúdez-Lugo, 2016; Amponsah-Tawiah and Dartey-Baah, 2011). Over the years, mining has contributed significantly to the gross domestic product (GDP) of Ghana. In 2013, mining accounted for 1.7% of Ghana’s GDP and about 19% of government revenues (Ghana Chamber of Mines, 2015). The Ghana Chamber of Mines also reported that mining contributed over 50% of foreign direct investment, 37% of export earnings and 1.1% of direct employment revenues. The US Department of Energy (DOE) estimates that 65% of coal, 92% of metals and 96% of industrial minerals are mined using surface mining methods (DOE, 2007). Generally, mining is a capital-intensive venture, with high operating cost, hence there is a constant demand for mining companies to seek efficient cost reduction and production maximization strategies. One strategy being pursued keenly is automation, which is noted to improve productivity, and worker safety at minimal cost. According to Parreira (2013), mining automation involves direct teleoperation whereby workers remotely control the mining process using computers from a control room.

Jan 1, 2019

The successful exploration for Austin Taylor and Gen. McRae from 1931 to 1940 obscured the fact that I was reaching a period of transition. This was true both in personal and business life. It was probably fortunate that I did not realize how great a change must come after I passed the age of 50. In the personal life of our family the change came when both our children left home to go to school or college. This made home a different place and, because of the absence of the children, Dorothy could devote much of her time and attention to the art she loved so well. She could spend long periods in New York, the center of the nation's art life. Vacations at Tahoe and long pleasure trips made the separation from the children less disturbing but it could never again be the same as it had been in the first 20 years of our marriage. The change In my business life was just as complete, though a little more gradual. While work for Bralorne and General McRae made the "bite" of the Great Depression less painful for us than it was for most consultants and their families, the fact that I was getting older made a new sort of work inevitable. I was 50 years old and the total grew rapidly. Planes and automobiles that made travel easier even in the wilds of Alaska and northern Canada still made it possible for me to look at new prospects, but increasingly often I was exhausted at the end of a day's climb and, if the nature of my work did not change there would soon be no more work. Fortunately work of a new sort came a little at a time. As I became a director of Bralorne and president of its American subsidiaries I had to take on more administrative work, and success of these operations made others want to employ me to help direct policy and value mines. I was also asked to arbitrate contests between mines when technical disagreements were so great that judges or juries could obviously not understand them My consulting for government agencies helped to

Jan 1, 1976

By C. Vasilescu

Phytotechnologies use plants to remediate various media impacted with different types of contaminants. These technologies can be implemented either in situ or ex situ. The affected media in which phytotechnologies can be applied include soil, sediments, groundwater and surface water. They are best applied at sites with shallow contamination of organic, nutrient, or metal pollutants that are amenable to one of five treatment options: phytoextraction, phytotrans-formation, rhizosphere, bioremediation, phyto-stabilization or rhizofiltration. Phytoremediation can be used along or, in some cases, in place of mechanical cleanup methods. Phytoremediation can be used to clean up metals, pesticides, solvents, explosives, crude oil, polycyclic aromatic hydrocarbons and landfill leachates.

Jan 1, 2006

By Robert L. Zook

Coal refuse slurry impoundments are dams constructed of coarse coal refuse to impound fine refuse (slurry) and water (25-30% solids). Both products are waste from coal preparation plants. A number of these structures in West Virginia, Pennsylvania and Kentucky were investigated to determine embankment stability. During the investigation a variety of embankment designs were encountered. The investigation determined the soil and geological characteristics of the embankments and the sites. This was accomplished by a test drilling and monitor installation (observation wells and piezometers) program, geologic study, and large scale mapping which allowed sub-surface profiles of the embankments to be constructed. The laboratory testing program concentrated on textural classification of the coal refuse, permeability and determining strength parameters to be utilized in the stability analyses. For the stability analyses, the Modified Fellinius Slip Circle, Simplified Bishop Slip Circle and Analysis for Translational Failure -were utilized. In all stability analyses hydrostatic pressure and earthquake were considered. This investigation indicated that 62% of the embankments analyzed are in a stable condition. The coal seam mined, the type of roof rock, and the gradation of the refuse influence the degree of compaction obtainable and the permeability of refuse. The shear strength of coal refuse appears to be controlled by its composition, moisture content, degree of compaction, amount and grain size of fines present. This investigation demonstrated these em¬bankments should not be treated as pure state-of-the-art dams; consideration must be given to the particular properties of coal refuse and the total refuse disposal system. Refuse dim slurry impoundments generally lack the site se- lection phase that is standard practice with siting most other types of dams.

Jan 1, 1974

By W. R. McDonald

The U.S. Department of the Interior, Bureau of Mines, conducted field tests on acidic copper tailing as part of its program to devise, improve, and demonstrate technology for stabilizing mining and mineral processing wastes. Results will be presented from successful 1/8-acre and 1-1/2-acre demonstration revegetation plots established in 1973 and 1974 on an abandoned copper tailing pond located on public land adjacent to Holden Village, Wash. The tailing was neutralized with treatments of either dolomitic lime or limerock and fertilized with processed sewage sludge and/or commercial fertilizer. Plant growth covering 60 percent of the surface was achieved on both test plots. Regar brome, Tegmar intermediate wheatgrass, and tall wheatgrass provided the best plant growth and surface coverage. In neutralizing the tailing, the target pH of 6.8 was not achieved; however, good plant growth occurred in areas where the pH ranged from 2.9 to 5.8.

Jan 1, 1979

By Musa D. Manzi, Raymond J. Durrheim, Richard T. Masethe

An investigation into the source mechanism of mining-induced seismic activity plays a vital role in understanding the various modes of failure observed in the underground deep-level South African mining environment. The seismic events data for this study was captured by the mine-wide seismic system operating at Kloof Gold Mine. This system comprises 40 4.5 Hz tri-axial geophones sampling at 6 kHz installed at locations that surround the stopes mining the Ventersdorp Contact Reef (VCR), Main Reef (MR) and Kloof Reef (KR). A set of 103,753 mining-related seismic events (-3.0≤ ML ≤2.7) that occurred during 2017 and 2018 was selected for this study. The mining depth of these seismic events ranges from 1600 – 4200 m; most located close to stopes mining the VCR ore body. The main criteria used to select a subset of events for detailed analysis were the number of stations that recorded the seismic event and the azimuthal distribution of the sensors.

Apr 26, 2022