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By Yueyue Ding, Yuanhui Li, Zhengrong Li, Pengfei Yu, Kunmeng Li, Zhipeng Xiong

The stress evolution and failure characteristics of overburden were studied during multi-stope mining for a gently inclined thin orebody. Firstly, an indoor physical experiment was conducted on the excavation of a multi-stope mine with an orebody dip angle of 20°. The results show that the vertical stress concentration area gradually shifts to deep-buried rock mass with the mining from shallow to deep buried stopes, resulting in shear failure originating from high stress. On the contrary, the pressure relief zone presents an asymmetric distribution characteristic that is biased towards the upper part of the goaf, resulting in large subsidence and tensile failure of the stope #1 and #2 roofs. Secondly, the numerical simulation model under the same geological condition was established to measure the roof deformation at different stages of mining. The numerical simulation results are in good agreement with the physical test results; the roof displacement is largest in stope #2, second-largest in stope #1, and smallest in stope #3. Finally, the evolution of deviator stress concentration, displacement field and potential failure zone of overburden under different orebody dip angles were studied. As the dip angle of the orebody increase, the deep-buried stope roof changes from deviator stress release to deviator stress concentration in different stages of mining, and shear failure is most likely to be induced when the orebody dip angle is 30°. Meanwhile, the closure displacement of the stope roof decreases gradually, while the tangential displacement increases, so the anti-sliding ability of the support bodies in the stope should be improved. The potential tensile failure zone gradually shifts from the center of the goaf to the upper part, and the deep-buried stope roof evolves from tensile failure to shear failure. Results of this research expected to provide guiding significance for stope support design to control roof deformation and failure, to ensure the safety of the stope.

Mar 2, 2023

By R. Owens, C. Roos, B. Hill, S. Rosenthal

It is common practice, and even legally required in many jurisdictions, to design two-lane haul roads in open pit mines to three and a half times the widest dimension of the haul trucks operating on the road. In open pit gold mines with high strip ratios, the road width has a significant impact on the economics of a design. It is possible to minimize the flattening of the highwall if the road width is reduced, assuming the width used is not needed to flatten the slopes for geotechnical purposes. With the use of autonomous haulage and pullouts, it may be possible to operate safely and efficiently on a reduced road width of two times the width of the hauling equipment.

Mar 2, 2022

By Muhammad Zia-ur Rehman, Sajjad Ahmad Baig, Gao Lei Fu, Muhammad Mohsin, Sobia Naseem

The environmental sustainability is linked back to human sustainability; the sustainability development comprises the environment, society, and economics. This study mainly focused on mining sustainability and its impact on the environment of Pakistan. For measuring the level and environmental mining sustainability nature to Environmental Impact Assessment (EIA) of the world’s second largest salt mine “Khewra,” Folchi and Phillips environmental sustainability mathematics (PESM) models are applied. The results indicated that Khewra was deemed to be potentially sustainable for the environment and quality of salt. The results suggest the delicate balance of maintaining sustainability successfully, regarding the mining process in Pakistan which has been affecting the local environment and community so badly. The paper lays emphasis on the potential significance of the model’s application for the attainment of sustainable mining goal. This study is essential for researchers,

May 11, 2020

By Thomas Novak, Philip Johnson, Richard L. Sanford, Lloyd A. Morley

Macintosh use in mine-planning applications lags DOS machines since many users have made significant investments in hardware and training for other environments. Macintosh use is becoming more pronounced in many other industries, and com soft-ware is of at least the quality of that available for DOS machines and many workstations. This paper describes attributes of the Macintosh computer family as related to many mine-planning problems and solutions including software, memory considerations, workstations, DOS compatibility, and networking.

Jan 1, 1993

By A. Haghighat

The Missouri University of Science and Technology?s (Missouri S&T) Experimental Mine is a teaching and research facility which has been excavated in limestone by mining engineering students over almost 100 years. The mine is currently being extended to a second level. Available fans for ventilation are two surface fans of 24 kW and two underground booster fans of 12 kW. The design of a ventilation network in conjunction with multi surface fans and booster fans entails a complex procedure. Ventsim Visual software modeling has been used for network analysis to determine the optimum surface and booster fans locations, blade settings, and speeds. Both natural and mechanical induced ventilation pressures have been taken into account. Three working faces on each level have been designated as target points that minimum air quantities are required. The model has been calibrated against a pressure and quantity survey. Design of ductwork, door/stopping positions and different fans characteristics have been examined. The optimum flow rate at identified working faces, efficiency and minimum energy losses and annual network power cost determine the best scenario. The optimum design has been determined for the ventilation network for the next 100 years. The optimum flow rate across working faces is the key criterion selected.

Feb 23, 2014

By L. B. Phelps

Many coal mining companies have potential surface mine reserves which either are known or suspected to have had prior drift mining activity on them. In many cases, there is no documentation on these mines or at best, very fragmented records. These undocumented abandoned underground mines are creating engineering, financial, and environmental difficulties and concerns for both surface coal mine operators and regulatory personnel. This paper examines the use of resistivity techniques in detecting entries of abandoned drift coal mines. The detection of such a drift mine entry would confirm the presence and orientation of an abandoned underground coal mine.

Jan 1, 1985

By Madan M. Singh

A new mining project can raise questions about what effect it will have on the community after it closes. Historically, little was done by communities to plan for and accommodate the changes in the economic infrastructure when a mine project is finished either after the ore runs out or if market conditions deteriorate and make it unprofitable. Projects that were underfunded were generally unable to withstand periodic market downturns. However, data in a recent study conducted by the Seidman Research Institute leads to the conclusion that, even when a mining project is terminated, there can be (and, in the specific case studied, is) a residual beneficial economic effect in the community, which lasts for a long period of time.

Jan 1, 2010

By Kanhaiya Mishra, Phanil. K. Mandal, S. K. Behera, P. S. Paul, Prashant Singh, C. N. Ghosh

The techno-economic and social benefits of cemented paste backfill (CPB) resulted in its wide acceptance by the mining industry. The Ordinary Portland Cement (OPC) remains the key binder but to diminish its economical constraints, suitability of alternate binders has been examined worldwide. The present study aimed to investigate the effect of partial replacement of OPC with fly ash on the CPB’s strength and to determine the most optimal mix to achieve the required strength (1 MPa at 28 days of curing) at the most cost-effective way using the Bayesian network (BN). The CPB mixes were prepared at 72 wt.% solid concentration with mill tailings (87–91%), OPC (6–13%), and fly ash (0–4%), and instantly after mixing, fresh (slump, bleeding, density) CPB properties were measured. The strength was tested at 7, 14, 28, and 56 days of curing and initially analysed through traditional model. The traditional models follow the aleatory principle and are considered not appropriate for geotechnical engineering. Hence, the BN model was developed and tested. The reliability of two classifiers in learning model structure was compared which gives Naïve Bayes as the highest reliable tool. The CPB’s strength is most sensitive to the OPC content. The most consistent mix(s) is mill tailings: 87–88%, OPC: 9–11%, fly ash: 1–4%. Adding fly ash at 89–91wt% mill tailings possesses high failure probability of the CPB. The collinearity test indicates that the fines percentage and chemical composition of CPB’s ingredients are highly correlated with its slump, bleeding, and strength development.

Jul 14, 2022

By Steve Kral

Americans are taking a more critical view of various environmental laws because the effects of those laws are becoming more pervasive and intrusive, according to William Perry Pendley. And Secretary of the Interior Bruce Babbitt is seemingly so unpopular in the West, he no longer campaigns there for Clinton Administration policies. Pendley is president and chief legal officer of the Mountain States Legal Foundation, a public service, non-profit law association that takes on property rights cases for people who cannot afford representation. He was one of the luncheon speakers at the 101st Northwest Mining Association meeting, held in Spokane, WA in early December.

Jan 1, 1996

By R. D. Williams

Several hydrometallurgical leach processes have been recently proposed for the recovery of copper from copper concentrates. These include the Cymet Process of Cypress Metallurgical Processes Corporation, the Arbiter Process of the Anaconda Company, and the Treadwell Process of Treadwell Engineering company(1). These processes and similar processes for recovery of other minerals, have several phenomenological similarities which make their quantitative description difficult at best. These include (a) the presence of more than one phase, (b) non-uniform mineralization of the feed concentrate, (c) surface and diffusional effects, and (d) a particle size distribution which varies with time. Semi-theoretical, rather than purely empirical, treatment of such processes in their developmental stages will result in a better understanding of the physico-chemical mechanisms in effect. This, in turn, will allow reliable process designs to be made on reasonable time scales for reasonable development costs. Once a production unit is built, such an approach will provide straightforward methods for process control and optimization. A research and development effort to determine criteria and procedures for semi- theoretically characterizing such mineral leach recovery processes has been initiated in a joint venture by the Arizona Bureau of Mines and the College of Mines at the University of Arizona. This group has as its task the mathematical characterization of hydrometallurgical leach recovery processes using semi- theoretical mechanisms for the underlying phenomena. The resulting models are experimentally verified and parameterized on the laboratory scale in such a way that they can be utilized with similarity criteria to provide reliable scaleup to production designs. This discussion will be centered around the elements of such an approach and how they fit together.

Jan 1, 1975

By Karl C. Dean

The current emphasis on environmental problems has focused attention on the massive nationwide accumulations of mine, mill, and smelter wastes that represent potential air and water pollution hazards. The pollution hazards can be reduced or eliminated by utilization or stabilization of these wastes. The U.S. Bureau of Mines, since the inception of the Solid Waste Disposal Act of 1965, has been conducting research to determine the practicality of various utilization and stabilization procedures. Investigations include partial extractions of desirable waste components and full utilization of the wastes as simulated soils or in ceramic or other structural products. Chemical, vegetative, and combined chemical-vegetative methods of stabilization have been actively studied. This report updates information previously developed by the Salt Lake City Metallurgy Research Center and presents the current status of antipollution solid waste work 1/,2/.

Jan 1, 1970

By Leslie C. Thompson

The heap leach process used for recovering gold from oxide and sulfide ores is operated as a closed circuit system in which the cyanide process solutions are continuously recy­cled. In a well-designed operation there is little or no dis­charge of cyanide to the environment. Spent leached ore residues are water washed to remove most of the trace cyan­ides and precious metals remaining after completion of cyan­ide leaching. After the washing step, small amounts of cyanide, metal-cyanide complexes and nitrates remain in the residue. Most of the cyanide and nitrate residue constituents exist in the pore water of the spent ore rather than in the solid mineral fraction. More than 90% of the complexed cyanides in a freshly washed ore residue are present as free cyanide or weakly complexed metal-cyanides. Natural volatilization and decom­position rapidly remove most of these easily dissociable cyanides from the spent ore. Only the stable, strongly com­plexed metal-cyanides, such as gold, cobalt or the ferrocyan­ides and other constituents such as nitrates have a long term persistence in the spent ore residue (Towill et al). Despite washing and natural removal mechanisms, spent ore has the potential to act as a point source of com­plexed cyanides and nitrates for soil and groundwater con­tamination if inadequately contained (Huiatt et al). The groundwater contamination is caused by the leaching of the soluble cyanide compounds and nitrates from the pore water of the residue.

Jan 1, 1990

By Steve Kral

Through advanced technology and innovative thinking, the mining industry has become one of the world’s leading industries in environmental protection. But it only takes one Summitville, Omai or, most recently, the Aurul gold tailings retreatment operation in Romania to provide ammunition to the industry’s critics in their attempts to sway public opinion against mining. So for the mining industry to continue operating with the public’s support, it must continue to improve its tailings waste-disposal processes and the dams that hold this waste. In January, about 120 specialists in the mine waste management field gathered together to discuss the available technologies and materials for controlling mine waste and mill tailings disposal. “Tailings and Mine Waste’00” was held at Colorado State University in Fort Collins, CO. This meeting, begun in 1978, is a continuing symposium. It provides a forum for environmental professionals to discuss the state-of-the-art in mill tailings and mine-waste disposal methods.

Jan 1, 2000

By Arcy R., D&apos George

Removal of S02 from smelter gases is being investigated, using an innovative technique that results in the almost simultaneous recovery and production of elemental sulfur. S02 is removed from the gas stream by scrubbing with suitable aqueous salt solutions or high-boiling organic fluids. The S02-laden liquor is then reacted with H2S Crystalline, high-purity sulfur is instantly precipitated and, after filtration, the regenerated liquor is recycled. The H2S required for the process is produced by reacting a portion of the recovered sulfur with hydrogen or with methane and steam. The chemistry and results of preliminary laboratory research are discussed.

Jan 1, 1969

By ZHONGLING ZHAO, WANTING SONG, GUOZHONG LIU, LEIXIN SHI, ZUI WANG, YUANYUAN LIU, KE GAO, DONGHONG JIANG, WANG LUO, PEICHAO LU, Jianwei Cheng, WANCHENG ZHENG, Gang Zhao, YUNGANG WANG, JIANBING ZHAO

Coal spontaneous combustion is one of the disasters occurring in underground coal mines. As a typical case, the spontaneous combustion of broken coal left in the longwall gobs often happen which could greatly interrupt the normal mining production. Such concealed thermal event is featured as rapid development and difficulty in locating “hot” spots. If such spontaneous combustion fails to be timely prevented and controlled, a large amount of toxic gases (mainly CO) and smoke could flow and diffuse in the underground working sections, which could present safety hazards for coal miners. In this paper, based on an coal spontaneous combustion event happened in a Chinese gassy mine, the fire ratios derived from the gas composition data obtained through the tube bundle mine atmospheric monitoring system are used in determining the fire status. A comprehensive and collaborative fire extinguishing effort including inert gas injection, underground pressure balance, and sealing enhancement are made to control the fire progress. Simultaneously, the effects of such works to control the spontaneous combustion event have also been quantified using the fire ratios to justify again. Finally, the danger of coal spontaneous combustion in gob is eliminated, and the longwall panel is successfully re-opened for normal production.

May 6, 2021

By Haydn H. Murray

Kaolin is defined and described as an industrial mineral. In addition the types of deposits -primary and secondary are defined and the genesis of kaolin from feldspars and other minerals discussed. The major deposits of the world found in the United States, Great Britain, Brazil, and Czechoslovakia are described along with many of the minor kaolin deposits. Four areas which have very large deposits of kaolin could, with technological breakthroughs to reduce viscosity significantly, become important factors in supplying the world markets which are increasing year by year.

Jan 1, 1977

By Donald M. Duncan

An acceptable source of concrete aggregate is available in Kansas City in a continuous, medium bedded, slightly dipping limestone unit. Removal is accomplished in shallow depth, 12 feet to 17 feet high, room and pillar mines. The accepted empirical design spaces 20 foot pillars 60 feet on center. A portion of the 20 foot unit is left in place for roof support. Rock and soil cover is variable to 100± feet maximum. Long-term stability of these mines is affected by numerous factors, including the above mine-rock profile, ground water conditions and mining practice. Crusher-run aggregate sells at the mine for $2.20 per ton, yielding a gross income of $2.00 to $2.80 per square foot of mine. Use of mine space for real estate development requires a new perspective in mine development. Mining practices to obtain long term stabile structures can become an over-riding factor as compared with minimum production costs and maximum extraction ratios. Poorly mined areas are unusuable for secondary purposes. Development cost for lease space in less desirable mines is substantially greater than those planned for a secondary use. Real estate development in mine space involves unique engineering problems. Properly engineered developments offer singular advantages. Warehouse lease space sells for $.50 to $1.00 per square foot per year; fully developed office areas may double these values.

Jan 1, 1968

By Snehamoy Chatterjee, Sanjay Kumar Palei, Smarak Das

Machine manufacturers’ recommendations on maintenance strategies of capital-intensive draglines are not always based on real data and therefore lead to losses from downtime. This paper proposes a preventive maintenance strategy for a dragline deployed in an opencast coal mine based on reliability-centered maintenance and failure-mode-effects analysis using real operational data. Reliability-centered maintenance replaced a cluster of critical failure components of the dragline while satisfying two specific conditions: (i) the components should be replaced at the earliest mean time to failure (MTTF) within the group and (ii) the time taken to replace all the parts should be equivalent to the maximum downtime within the group. Estimated threshold weightage factor identified twenty-six critical failure components for the preventive maintenance strategy, and clustering of components divided them into nine groups. In a group, the loss that is expected to occur by replacing some of the components before their failure, and the gain by reducing the overall maintenance downtime, has been explained through a cost-benefit analysis. The total net profit generated is calculated as US$200,178. This clustering activity also led to a reduction of annual downtime by 231 h, whose approximate market price as equivalent coal production costs $295,365.

May 28, 2020

By S. A. Smith-Hamm, E. A. Sarver, A. S. Cox

Appalachia is an increasing concern, as unnaturally high TDS and/or associated specific conductivity (SC) may contribute to deteriorated stream ecosystem health. The aim of this preliminary study was to explore the efficacy of accelerated leaching as a means of minimizing long-term TDS/SC generation by problematic overburden materials. Five spoil samples were collected and leached using simulated rainwater solutions under ambient and acidified pH conditions. SC and pH were monitored during each leach cycle, and inductively coupled plasma-mass spectroscopy (ICP-MS) was used to determine how leaching conditions affected the release of specific ions. This paper highlights the results of both jar and column leaching tests. Among the most significant findings was that for certain spoil materials, the SC in the leach column effluent was effectively reduced when the spoil was first leached with acidic rainwater followed by ambient rainwater, as opposed to leaching with ambient rainwater alone. This suggests that accelerated leaching might aid in the long-term stabilization of some materials.

Jan 1, 2015

By J. G. Groppo

The Andritz Ruthner Inc. hyperbaric filter was evaluated at a pilot scale for dewatering fine coal cleaned by froth flotation. The pilot scale dewatering testing was conducted at a solid feed rate ranging from 100 lbs to 200 lbs/hr-ft2. Effect of hyperbaric operating parameters and addition of various surfactants and flocculants were evaluated on dewatering of fine coal. The tests data indicated that for the minus 100 mesh and minus 28 mesh clean coal product, the Andritz hyperbaric unit provided filter cake containing 23 percent and 14 percent moisture, respectively.

Jan 1, 1996