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By J. G. Groppo

Hyperbaric filtration was evaluated at the laboratory scale for dewatering fine coal cleaned by froth flotation. A laboratory pressure filtration procedure is described to obtain uniform cake structure from dilute slurries containing a significant amount of coarse material. Baseline tests were conducted varying filter operating parameters such as driving force, time, cake thickness, percent solids, viscosity and pH to determine optimum operating conditions for eventual application on a continuous pilot scale hyperbaric filter.

Jan 1, 1994

The heat of immersion of coals in different immersional liquids is measured as a function of particle size and moisture content. Decrease in particle size shows a concomitant increase in the heat of immersion. The heat of immersion is dependent upon the nature of immersional fluids. In addition the nature of moisture present in coal influences the heat of immersion.

Jan 1, 1993

By George R. Stephans

The Climax Mine is a panel caving mine which has had a long history of incidents of severe ground control problems. The nature of the ore deposit, which lends itself to the caving meth- of of production, a1 so makes the mine susceptible to large scale stress concentrations which are referred to as ?weight? problems. These problems have increased with increased production and also with expansion to deeper mine levels. During the past twenty years the mine has had to learn to cope with these problems in order to remain in operation. A number of practical guidelines and useful techniques have emerged from these efforts. The purpose of this paper is to share a few of these ideas. The Mine is located near Leadville, Colorado on the continental divide at an elevation of 3450 meters. The ore body is a large low grade deposit of disseminated molybdenum sulfide. It measures about 1200 to 1600 meters in diameter and it had an original depth of about 660 mters. The Mine has been in operation since 1918 and the massive nature of the ore body together with its blocky, highly fractured condition made it natural for the caving system to have been adopted for production at an early date. Open pit mining was started in 1973. The total plant has a capacity of more than 50 thousand tons per day, and more than 400 million tons of reserves at an average grade of 0.310 percent molybdenum disulfide remain to be produced.

Jan 1, 1982

By Su Yang, Pang Shun, Xiaoding Xu, Guodong Yang, Hengfeng Liu, Meng Wu, Yuejin Zhou

By introducing the hydrochemical damage variable of coal gangue granular material, this paper analyzed the evolution law of gangue mechanical parameters with hydrochemical damage. By constructing a gangue damage model considering multifield coupling, the damage mechanism of gangue under multi-field coupling was revealed from the microscopical aspect, and the influence law of gangue damage mechanism on the dissolution of toxic substances under multi-field coupling was obtained: the conditions of Test 1 have the greatest influence on the porosity of coal gangue, and the damage of coal gangue is the greatest. Cu, Zn, Cd, and Pb are more easily leached under acidic conditions. The coupling effect of seepage, temperature, and chemical field can promote the formation of secondary voids, change the voids, and form migration paths in coal gangue. The kinetic model of toxic leaching of coal gangue under multi-field coupling can be well characterized by Elovich equation. The release mechanism of heavy metals is mainly manifested as delayed diffusion or dissolution in the early stage, diffusion and dissolution in the middle stage, and depletion in the late stage.

Nov 23, 2023

By R. W. Reisinger

An historic underground copper mine in Wyoming is discharging neutral but copper-laden water into a pristine creek. The EPA-deferred site qualifies for reclamation by the Wyoming Abandoned Mine Land (AML) program; restoring the discharge so that the creek can eventually support a trout fishery is the cleanup goal. Hydrological and geochemical investigations underground have suggested two sources of mine water: one clean and the other copper-containing. Results of bench-scale and pilot-scale tests support the viability of using low-cost passive treatment techniques to reduce copper concentrations in the near-freezing mine discharge.

Jan 1, 1998

In spite of a global economy that continues to seesaw and a U.S. Congress that is at odds with the president and themselves, cities around the world are still spending billions on their infrastructure. And that bodes well for the underground construction and tunneling industry and the professionals who work in it. In June, 1,405 of those professionals gathered in San Francisco, CA for the Rapid Excavation and Tunneling Conference (RETC). In addition to the first rate technical programming, attendees were able to see first-hand the latest in tunneling technology from 127 exhibitors who occupied 152 booths. Two short courses preceded the conference and two field trips were offered following the conference.

Jan 1, 2011

By L. F. Engle

There continues to be a certain magic attached to the word "Automation". When properly planned for, engineered, installed, and operated, the magic truly does take place - witness certain publicized mineral processing, metallurgical, and chemical plants. They operate successfully with few people, instead of previous dozens as in similar facilities not automated. Production quality has improved. Maintenance costs have been lowered. When such welcome results are achieved, it's proved to be a function of method and procedure in establishing criteria for choosing the intelligence and control systems followed by skilled choice of the specific elements used. The criteria, the bases for decision, are associated with design, construction, startup, operations, and maintenance. How to go about automating any process system to achieve the optimum profit depends on attention to all those aspects of a project. None of them can be forgotten if maximum satisfaction is to be gained. Control loops that look wonderful on an equipment. Piping, and Instrumentation diagram can suddenly turn into costly and. annoying problems in the field if there has been too little coordination of design. Panel boards that are literally works of art just before startup can become the largest of white elephants if an air header is inadequately sized and the pneumatic control circuits are sluggish. Conveyor belt replacement costs can skyrocket if a critical discharge chute far away from immediate operator attention lacks a simple yet effective clog-chute switch. Planning, execution, and followup of the work, the skills, and function of-the automating material can make any new project a success. An integrated owner contractor, producer-engineer approach is the key.

Jan 1, 1963

By W. Lorenz

The responsible treatment of natural resources, including mineral raw materials, contributes to the protection of the environment. The management of resources and the environment encompasses reduction of emission through application of environmentally friendly processes, economical use of resources, recycling and substitution, application of energy saving processes, land reclamation and recultivation, as well as a well balanced regional and land use planning. A variety of materials are needed for measures to protect the environment. Many of these materials are, or to a large percentage consist of, mineral raw materials, which become effective either directly or indirectly in their natural state or after an appropriate industrial treatment. We call them environmental minerals. Although extraction and processing of these mineral raw materials destined for use in the protection of the environment, may have a negative impact on the environment on one hand, preventive or curing measures to protect the environment on the other would not be possible without them. We have to accept certain smaller burdens of the environment, which naturally will have to be kept at the lowest possible level, in order to avoid or minimize greater damages to nature. In the broad group of industrial minerals and rocks there is a wide variety of mineral raw materials, which lend themselves for countermeasures in favor of the environment. To hamper their production and processing through excessive environmental regulations would make the protection of the very environment more difficult or even impossible.

Jan 1, 1995

By D. K. Mynear, J. S. Gardner, S. Mittle, A. A. Campoli

West Virginia, although having adequate solar insolation, has witnessed very little actual solar development to date. The reasons for this lack of development are varied, but the primary obstacles to future development appear to be the absence of state-level policies and regulations promoting growth in the solar industry. West Virginia possesses large tracts of under-utilized land throughout the state created by previous mountaintop mining operations that could theoretically be re-purposed for solar farm development. Accomplishing this task will require not only revisions to the current legislation, but also acceptance by utility companies, landowners, and mining companies. Solar developers will need confidence that they can secure revenue from the electricity and Renewable Energy Certificates (RECs) generated by solar projects. Additionally, solar companies will need assurance they will be protected from any non-related environmental liabilities that could arise in the future. The primary avenue in bringing significant solar development to West Virginia will come through large corporate clients demanding or partnering with utility companies for incorporation of solar options into their energy portfolio to help meet established sustainability goals. This scenario has been witnessed in other states where a large client demands renewable options. Solar development could also represent a means through which mine operators might alleviate some of their reclamation and bonding obligations; where the landowner could supplement income from their underutilized land holdings; and where displaced miners could be repurposed in solar installation/maintenance jobs. Utilizing data from the West Virginia Permit Database, this report identifies several mine sites that hold potential for solar development in the future. INTRODUCTION The diversification of energy sources in the United States (US) has seen major shifts during the past decade resulting from: • A sudden abundance of low-cost natural gas becoming available through advanced horizontal drilling and hydraulic fracturing techniques. • Incentive-driven policies leading to new development in alternative energy. • The emergence of renewable energy sources, proliferated by state and federal level incentives and falling capital costs. Coal was once the primary low-cost fuel source for the generation of electricity in the US for most of the last century, providing approximately 50 percent of the total production capacity. However, within the past decade lower-cost natural gas has overtaken coal as the primary source of fuel used in electricity generation, and renewable sources have steadily grown to account for approximately 10 percent of the overall mix.

Jan 1, 2019

By Biswajit Samanta, Pranjal Pathak

This article presents a customized genetic algorithms (GA) with new crossover and mutation operators to solve the short-term production scheduling problem of multi-mine mineral value chains (MVC). The preceding problem consists of determining the extraction sequence and destination allocation of blocks from all the mines collaboratively while closely meeting the quality and quantity requirements of the processing units subject to relevant technical and operational constraints. The short-term production scheduling is carried out at shorter scales wherein the operations are modeled in a great detail with large number of constraints. This makes the industry-scale instances of the problem computationally intractable for standard mixed-integer programming (MIP) solvers. Thus, a GA-based heuristic approach is developed to obtain nearoptimal solutions to the large-scale instances of the problem in a reasonable amount of computational time. Computational experiments show that the developed GA-based method is a promising way to handle industry-scale instances of the problem. Moreover, the sensitivity analysis on various parameter combinations of crossover and mutation operators indicates that the customized global mutation operator, when used in combination with the customized crossover operators, took on average 12.5% less time than the customized local mutation operator to converge to a solution.

May 21, 2022

By Caroline Gerwig, Joseph R. Wickline, Zach Agioutantis

In longwall mining, the progressive caving of the roof allows stored energy to dissipate over an extended time. However, in some cases, the roof strata above the longwall panel are unusually strong and do not break with the movement of the working face. Instead, the roof material bridges over the expanse of the longwall, forming an unstable beam. Later, when this beam breaks, the stored energy can release suddenly, causing a seismic event to propagate to surrounding mine workings. The focus of this paper is to estimate the size of beams that form over longwall panels to the seismic energy recorded by the mine. Analytical calculations are used to verify two-dimensional models of longwall roof beams to determine the strain energy and gravitational energy developed, which is then released upon strata failure to surrounding mine workings. Models are developed using RS2 to model the stress, strain, and deflection along the bottom of the longwall roof beam to calculate gravitational and strain energies. Gravitational energy is shown to be the main driving factor in energy release, except for the beams with low heights. Analyses allow the determination of beam characteristics based on seismic data. The analysis is refined using swelling factor to compare various beam drop heights. The models show an increase in seismic magnitude for higher drop heights. However, the actual data provided by the Buchanan mine displays a decrease in seismic magnitude with increasing drop height, indicating that energy is dissipated into the broken gob material as drop height increases.

Jul 1, 2023

"INTRODUCTION Twin Metals Minnesota (TMM) (operating as a joint venture between Duluth Metals and Antofagasta PLC) assumed control of the property in 2010. Amec became involved with the project in 2011 and in 2012 incorporated additional drilling in order to update historic resource estimates. The Maturi geological model and resource estimate was updated in 2014 to incorporate additional information obtained during 2013 and 2014 drill campaigns. In 2017, Amec was purchased by the Wood Group and is now known as Wood. Geology The Twin Metals Minnesota (TMM) Maturi, Maturi Southwest, Birch Lake, and Spruce Road properties are located in northeastern Minnesota (Figure 1). This talk discussed the Maturi deposit only, although all four deposits share similarities. The following geology is summarized from Peterson and Severson (2002).Maturi lies within the Superior Province of the Canadian Shield which is exposed in central and northeastern Minnesota and extends northward into Ontario. In eastern Minnesota, the Midcontinent Rift System developed during crustal scale extension in the Mesoproterozoic Era. The rift system is traceable, as exposures of mantle-derived tholeiitic to subalkaline mafic lava flows, intrusives, and rift-filling fluvial sedimentary rocks, and in the subsurface as a gravity anomaly (high), from the eastern end of Lake Superior, arcing west across the lake basin, and extending south-southwest to northeastern Kansas. Intrusion of the Duluth Complex, circa 1,108 - 1,099 Ma, was related to rifting and is co-genetic with the North Shore Volcanic Group mafic volcanic rocks that form the hanging wall of the Duluth Complex to the east. Cu-Ni-precious metals (PM) mineralization including Pt, Pd, Au and Ag within the Duluth Complex is hosted by mafic to ultramafic intrusive rocks that are part of the overall intrusive complex. The Duluth Complex is defined as a more or less continuous mass of mafic to felsic plutonic rocks that extends northeastward for more than 170 miles (275 km) in an arcuate fashion from Duluth nearly to Grand Portage in Minnesota. It is bounded by a footwall of Paleoproterozoic sedimentary rocks and Archean granite-greenstone terranes (Peterson and Severson, 2002), and a hanging wall largely of comagmatic anorthosite, rift related flood basalts, and hypabyssal intrusions of the Beaver Bay Complex. Mineralization is hosted in the basal mineralized zone (BMZ) of the South Kawishiwi Intrusion (SKI). The SKI magmas intruded sub-horizontally between hangingwall Anorthositic Series (AN) rocks and footwall granitic rocks of the Neoarchean Giants Range batholith (GRB). The Maturi local geology and the deposit footprint (shaded orange) is shown in Figure 2."

Jan 1, 2018

By L. J. Tucker

The magnetite orebody at Pea Ridge strikes NE-SH and dips at about 800 to the SE. The ore is high grade magnetite with a strike length of over 600-m and a maximum width of over 180-m on some of the levels. The shape and the mineral content of the iron orebody have been fairly consistent so far. The iron ore and surrounding basement rocks are Precambrian in age. These rocks are usually very competent, about 400-m of sediments lie over the ore.

Jan 1, 1991

By Hemendra N. Kalia

Several attempts have been made in the past sixty or so years to commerciliaze the vast oil shale deposits of the United States of America. However, the industry has yet to become viable and economic. To date, it has not been possible to produce oil from the oil shales at a competitive price when compared to the oil produced from oilfields by conventional methods. However, the development work has been quite fruitful in furthering the art of thick bed mining and technology of in situ retorting. The in situ method has the potential of recovering oil from thick beds and the resource recovery potential is much greater than that from underground mining and surface retorting. In situ methods require that the shales/ marlstones be fragmented ' in place to induce adequate porosity and permeability to allow in situ' heating of the fragmented shales. This can be accomplished by using explosives. However, it has been found that the existing blasting systems, though very efficient, are somewhat lacking. The explosive become insensitive when shot in multiple vertical decks. They can also become insensitive when spaced horizontally at close proximity to other charges. Also, since the blasting is done in a very limited free face, this limits the delay time that can be allowed between charges. Consequently it is not always possible to predict the performance of the blasting system on a routine basis. Furthermore, since it is not possible to undertake secodary blasting, it is imperative that the blast design function properly. Recent, successful retorting by Occidental Petroleum Company of retorts seven and eight suggests that some of these problems may have been overcome. This paper addresses some aspects of in situ retorting and problems those have impeded the development of a viable oil shale industry in the U.S.A.

Jan 1, 1983

By F. Habashi

The Republic of South Africa is a heterogeneous mixture of Black Africans, Afrikaans, British, Indians, Malayans, French Huguenots, and many others from Europe and Asia. A decisive date in its recent history is the collapse of the Apartheid Regime in 1994. For a metallurgist, South Africa is the country of diamonds, gold, platinum, and many other metals. In 1887 Cecil Rhodes (1853-1902) was able to take control of the De Beers Mining Company after the discovery of diamonds at Kimberly in 1866. It was there where the so-called School of Mines was inaugurated in 1896.

Jan 1, 2010

By T. M. Gurr

In recent years the need for reducing energy costs has led many in search of alternative fuels, examples are gasohol, "cow power", oil shale, biomass, peat and many others. We have been involved with several peat resource evaluations and would like to share with you some of our observations and experiences. We hope our experiences may help you in your evaluation of existing or future projects where peat is considered as an energy resource. The items that we will cover are listed as follows: ? Peat Uses, Occurrences, and Characteristics ? Identifying Exploration Targets ? Peat Exploration ? Peat Prospecting and Reserves Analysis ? Peat Harvesting and Reclamation Assessments ? Summary and Conclusions

Jan 1, 1983

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Mine explosions are one of the most concerning risks related to underground coal mining, as a single gas explosion can cause injuries and fatalities among miners. Underground infrastructure seals and build-in-place (BIP) refuge alternatives (RAs) are employed to isolate an area from active workings to mitigate coal mining-related accident risks. They are designed to withstand blast pressures from a possible accidental detonation of the contained gas or a coal dust explosion. Crosscut seals and BIP RAs, typically consisting of steel-reinforced concrete, are prone to strong convergence and have a significant leakage potential due to high convergence damage near mined-out areas. The roof-to-floor convergence can change the structural integrity of these structures, and altered structural integrity can lead to less explosion resistance capability. Hence, a thorough analysis is needed to further understand their explosion response under various strata conditions.

Jul 1, 2023

By R. Bokotko, J. D. Miller, J. Hupka

Laboratory results from an initial study on the removal of SO2 from gas mixtures are reported using air-sparged hydrocyclone (ASH) technology. Tap water and alkaline solutions were used for absorption and the influence of gas flow rate, water flow rate and length of the ASH unit were investigated. Complete removal of SO2 was possible with very favorable kinetics. The efficiency of sulfur dioxide absorption from air using the ASH is compared with the efficiency of conventional technology.

Jan 1, 2002

By J. C. Motz

During the past five years, Rexnord has developed, tested and introduced the Nordberg Omnicone Crusher to the industry. When the Symons brothers invented the cone crusher over 60 years ago, they employed the principle wherein the length of the crushing stroke was related to the free fall of material by gravity. This permitted the material being crushed to fall vertically in the crushing chamber; and in effect, caused the particles to be crushed in a series of steps or stages as the particles got smaller due to the crushing action. This also helps to reduce the rate of wear of the liners since the sliding motion of the particles is minimized.

Jan 1, 1986

By S. Que

Local community acceptance is a key aspect of planning and managing mining projects, whether through sustainability assessment and reporting or corporate social responsibility programs. However, there has been very little research to understand the determinants of community acceptance. This paper seeks to identify key mine characteristics and demographic factors that influence individual acceptance of mining projects. Six demographic factors and 16 mine characteristics were selected based on literature review. Four of the six demographics factors were confirmed to be significantly (p < 0.05) correlated with people?s attitude of the importance of the mine characteristics. All sixteen mine characteristics are identified as important factors. The most important mining factors are Job opportunities, water shortage or pollution, air pollution and land pollution. Both the mining and control groups have same opinion of 12 mining characteristics and differ on four (infrastructure improvement, labor shortage for other businesses, noise pollution, and mine life). During design and management of mines, this data can be used as a reference. This result will facilitate better choice experiment (survey) design for discrete choice modeling. Such discrete choice models can provide a viable framework for data-driven community engagement and sustainable mine management.

Feb 23, 2014