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By R. F. Hadley

Alluvial valley floors constitute a valuable land resource and have been important to ranching operations in semiarid western United States. This resource may be in jeopardy locally if the alluvial deposits are disturbed by surface mining of coal deposits. Erosion problems caused by poor land-use practices can cause trenching of the unconsolidated alluvium with a consequent lowering of the water table and depletion of soil moisture needed to support vegetation. Historical evidence of this sequence of events is abundant in geologic literature and serves as the basis for assessing potential impacts of surface mining. The potential geomorphic impacts of surface mining on alluvial valley floors with regard to fluvial processes are: (1) disruption of the longitudinal profile followed by valley trenching and high sediment yields downstream and (2) replacement of the excavated alluvium with unconsolidated material that does not have similar physical characteristics and may be susceptible to erosion. Mining may disrupt the existing hydrologic framework affecting streamflow, ground-water levels and water quality of both surface water and ground water. Although functional hydrologic and geomorphic processes are similar, each valley represents a complex environment that does not submit to broad generalizations.

Jan 1, 1978

By M. Gunter, M. Buzon, B. McNamee

"A Google search on talc asbestos will yield over 500,000 hits – the reason being the growing number of civil lawsuits in this area. Historically the litigation was centered on amphibole-containing industrial talc. There was no debate these talcs contained amphiboles, but the issue was the definition of asbestos. Ultramafic hosted talcs, however, are formed in such a way as to not favor the formation of amphiboles in the talc; they can occur in the surrounding black-wall, also the serpentinite host rock is in direct contact with the talc. Thus allegations can be made non-asbestiform amphiboles or non-regulated serpentine group minerals can occur in the final products. INTRODUCTION Gunter (1994) wrote the following in regard to the question “What is asbestos? “The question yields different answers depending upon the audience. To a mineralogist, asbestos is a mineral form. To an engineer, it is an industrial material with several useful properties. To a medical doctor, it is an agent that might cause certain diseases. The third answer invokes several more issues: to a lawyer, a possible lawsuit; to a news reporter, a story; to an asbestos abatement worker, a job; and to a public school administrator or a parent, a nightmare.” The main function of that article was to try and provide background information to be taught at the college level to help students understand some of the issues associated with the use of asbestos in our modern society, and especially its use as a fireproofing agent in schools and public buildings. At that point in time one of the main issues was asbestos abatement as the mining and use of asbestos was waning as its health risks became more clearly known in the occupational setting. Now over 20 years later the current issue we are dealing with herein is “asbestos” occurring naturally in talc. This is a well know concern for those in the talc industry and they have been working on methods to ascertain if their products contained “asbestos” since last century. As such our articles will focus more on issues emerging from recent litigation, and the confusion that occurs, especially in the “asbestos” nomenclature as the mineralogist, engineers, doctors, and lawyers previously mentioned try to communicate. And lastly we need to remain cognizant of the fact that people are still dying of mesothelioma in the US. As a last resort to recoup expenses as they are dying they often respond to the TV advertisements we’ve all no doubt seen."

Jan 1, 2016

By H. R. Hammond

The situation of The Consolidated Mining and Smelting Company of Canada Limited, or Cominco, may be somewhat unique in that the Company is not only a manufacturer of ammonium nitrate, but as a mining company is a major user of its own product. This situation has resulted in highly successful application of ammonium nitrate-oil explosives. Several noteworthy techniques have been developed and others have been improved. Use of this material in the mining industry has led ammonium nitrate producers to adopt the term nitro-carbo-nitrate or INN for ammonium nitrate-oil blends. A small blending plant at Cominco's largest mining property, the Sullivan Mine, at Kimberley, B.C., is producing more than 80% of all the explosive used at the Sullivan, and is supplying two other Cominco mines. Application has required intensive research to determine the best forms of ammonium nitrate for use in small holes drilled for development and long-hole stoping. It has led not only to experiments to determine the best blending oil, but also to development of loading techniques to the point where NCN is being moved through loading tubes over 700 feet. It has required research into mining practices such as hole arrangement and blasting of development cuts. It has resulted in the development of a special product for secondary breaking. All this has been accompanied by the recognition of the importance of insuring safe practices at every stage.

Jan 1, 1963

By W. R. Reed, D. E. Pollock, T. W. Beck, J. A. Organiscak, J. D. Potts

In underground continuous mining operations, ventilation, water sprays and machine-mounted flooded-bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements — such as face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation and equipment operator positioning — can have impacts on the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Pittsburgh Mining Research Division for remotecontrolled continuous mining machine operators as well as haulage operators at 10 U.S. underground mines. The results of these respirable dust surveys show that continuous miner exposures varied little with depth of cut but are significantly higher with exhaust ventilation. Haulage operators experienced elevated concentrations with blowing face ventilation. Elevated dust concentrations were observed for both continuous miner operators and haulage operators when working in crosscuts driven into or counter to the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposures attributable to particular mining configurations. These findings form the basis for recommendations for lowering face worker respirable dust exposures.

Jan 1, 2016

By C. B. Kettering

In the early operations of the Inspiration Consolidated Copper Company, which extended from 1914 to 1926, the ore as mined contained principally sulphide copper minerals, manly chalcocite (Cu2S), This ore was milled in a 20,000-ton concentrator and the copper was recovered as a flotation concentrate which, was smelted at the nearby plant of the I ternational Smelting and Refining Company. In those days no attempt was made torecovercopper from any oxide minerals present. As mining operations progressed it soon became evident that the proportion of oxide minerals present would steadily increase, and. it was realized that some method of treatment would have to be developed whereby copper could' be recovered from both oxide and. sulphide minerals contained in the ore. A research program was instituted and after some years of experimental and, pilot plant work a new hydro-metallurgical process was developed whereby it became possible to extract copper from both the oxide and. sulphide minerals in a single leaching operation. The solvent adopted consisted of a mixture of sulphuric acid and ferric sulphate,' Following dissolution, the dissolved copper would be recovered by electrolysis. Also in the process of electrolyzing, spent solutions of sulphuric acid, H2SO4, and. ferric sulphate, Fe2(SOk)3, would be regeneratede and. somade available for continuous reuse. The process appeared to be a success and the decision was made to build a full-sized leaching plant for the future treatment of I spiration mixed ore. Construction was started and the leaching plant was completed in 1926, With the start of ferric-sulphate leaching the Inspiration Concentrator was shut down and, with the exception of a few short time runs has not operated since that time. The ferric sulphate leaching process served. Inspiration well for some 30 years and during that time won a name for itself as a classic example of hydro-metallurgical treatment of mixed sulphide oxide ores. Originally the plant was designed. to process some 7,500 tons per day of a mixed ore containing about 1,2% copper, of which 60% was present as oxide and. 40% as sulphide, Down through the years various improvements were made for the purpose of increasing plant capacity and as well to change the limiting 'factor of sulphide-oxide ratio, The final result was a leaching capacity of 9,600 tons per day when treating a 1% copper ore with a reversal of the sulphide-oxide ratio to 60% sulphide and 40% oxide.

Jan 1, 1958

By L. W. Saperstein

Surface mining of coal is undoubtedly one of the more controversial aspects of the mineral industries today. There is a constant tug between the need for readily available and inexpensive energy supplies and the desire to minimize disturbance to the land. Without a doubt, surface mining severely disturbs the land surface. The duration of this disturbance, from a minimum of a few months to a maximum of infinity, however, is strictly dependent upon the mine operator's willingness to reclaim. Surface mining critics claim that it is impossible to ameliorate the detrimental effects of this mining to insignificance. The more vocal critics, indeed, are calling for complete abolition of surface mining for coal. Thus, they do not believe that it is possible to restore surface- mined land to pre-mining conditions. As a consequence of this position, an adversary relationship has developed between the operators and their critics who, simultaneously, believe they are doing their best for the United States. In a forum of mining experts, there is little need to recount the kind and amount of devastation that can result from poorly reclaimed land. This has been done numerous times, including once 1 by the author. Of particular interest to this paper, though, are the environmental hazards associated with contour strip mining. In addition to the problems of area mining: denudation of vegetation; exposure of toxic spoil; increase of erosion runoff; etc.--contour mining has the very real problem of landslide due to the outslope stacking of overburden. Contour mining is understood to be the extraction of coal from a hillside outcrop such that the resultant pit follows, or nearly follows, an elevation contour. The problem with contour mining as usually practiced is that the spoil from the cut, or the first cut if multiple cuts are made, is placed on the outslope. If this slope is steep, the resulting pile is difficult to stabilize, generally erodes swiftly, and may fail disastrously.

Jan 1, 1973

By Silvia H. M. Grimaldi, Afonso H. Martins

The scope of this experimental work was to study the yttrium extraction and stripping behaviour in a solvent extraction system with mono(2-ethylhexyl)2-ethylhexylphosphonic acid (IONQUEST 801) in a chloride system The study was performed for only one contact between organic and aqueous phases The experiments were carried out according to a factorial design. Due to the statistical analysis and its experimental proof, the optimum conditions for maximum yttrium loading into the organic phase of the extraction stage were 16 minutes for time of contact between phases, 980 rpm of stirring intensity and pH=2.3 for the aqueous phase of the sovent extraction system. The optimized experimental conditions by the statistical approach for the stripping stage were: time of contact between phases equal to 20 minutes, 1050 rpm of stirring intensity and 1.75 M HCI into the stripping aqueous solution.

Jan 1, 1995

By S. S. Pathak, S. Mishra, M. H. Tyeb, A. K. Majumder

Roping in hydrocyclones is a well-known phenomenon in mining and mineral industries which put serious restrictions on their continuous and maintenance free operation. Roping is mostly observed in association with high underflow solid concentrations which can be attributed to higher fraction of solids reporting to the underflow or the feed solid concentration itself being higher. This paper proposes a newly designed spigot with a truncated conical geometry which can allow for a rope-free discharge at higher feed solid concentrations. The experimental observations revealed that in the operation of a 50.8-mm-diameter hydrocyclone, roping ensued at 10% to 12.5% (wt%) feed solid concentration depending on feed inlet pressure for the cylindrical spigot, whereas with the modified spigot, rope free discharge was attained even at 25% (wt%) feed solid concentration.

Jan 8, 2022

By Thomas P. Goslin

T e mechanization of industry to reduce labor costs and to improve product quality is affecting he scale industry as it has affected many other industries. With increased emphasis on higher production rates many operators are experiencing difficulty in overcoming production problems where weight is a factor. Unfortunately, the scale industry has not shown the development over the last twenty-five years that other instrument industries have. For centuries the balance scale has been the standard and the workhorse of most weighing operations. In recent years considerable effort has been applied to designs to make balance scales more acceptable to industries employing automatic or semi-automatic processes. For the most part the designers have not attempted to replace the basic scale but toautomate functions of material handling and human judgement. Modern dump scales, for example, will accept material from a conveyor until a preset amount of material is on the scale, At this time the scale turns off the conveyor, dumps the load of material and repeats the operation with any desired timing. These improvements have helped industry. Even the scale observer has been replaced with devices which observe the scale reading and operate on weighed objects according to their weights. In spite of' the application of automation to the material handling, the balance scale has not been completely satisfactory. One reason for this is fairly evident when one considers the construction of the scales. Inherently, they are slow devices because of the inertia of the beams. The beam scale, primarily a static measuring device, is at the best limited to slow dynamic measurements.

Jan 1, 1958

By M. T. Ityokumbul

The effect of reaction conditions on the desulphurization of oil sand coke residues has been studied. The variables investigated were temperature, reaction time, heat transfer resistance, and mode of caustic soda addition. The results obtained show that oil sand coke desulphurization increases with temperature, reaction time, and heat transfer rate. In an oxidative environment, coke combustion during molten caustic leaching (MCL) commences at temperatures above 500°C. The mode of caustic addition has no effect on coke desulphurization.

Jan 1, 1995

By K. N. Han, H. C. Cho, R. Kim

"A comprehensive analysis of the effect of OH- on various cations in hydrometallurgical systems has been investigated. Cations chosen for this analysis included groups 1A and 2A, rare-earth elements and other common transition metal ions such as Cu2+, Fe2+, Fe3+, Mn2+, Ni2+, Co2+, Ag+, Cd2+, U4+, UO2 2+, Hg2+, Al3+ and Zn2+. The Newton-Raphson technique was used to calculate and plot various metal species over a wide range of pH. This study has clearly shown that by adjusting the concentration of OH-, the separation of Fe from Mn, U from V, Ce and Eu from other rare-earth elements, and In from Sn is possible. The effects of hydrated metal ions on the separation and removal of various metals from each other under various conditions is discussed.IntroductionThe primary purpose of hydrometallurgical processing is to extract, remove and purify various metals from diverse sources. Hydrometallurgists are frequently preoccupied by the extraction of cations in metallic form, but overlook the important role anions play in such processes. A proper choice of anions can determine the fate of successful extraction, removal and purification of metals (Esmaeili et al., 2005; Brbooti et al., 2011; Wei et al., 2005; Jeppesen et al., 2005; Al-Tarazi et al., 2004), and also separation (Farha et al., 2011; Sevenich and Fritz, 1983; Rashid, 1974) of cations from various solutions.In this study, the authors have examined some of the effects that anions play in various solutions. The anion considered in this study was the first hydroxide, OH-. Other anions, such as Cl-, Br-, I-, and CN-, will be dealt with in the second part of the series of two papers."

Jan 1, 2015

By G. Konstantopoulou

Environmental degradation due to abandoned quarries is an international problem, more intense when these sites are found in urban or suburban zones, in environmentally sensitive areas or are visible from sites of special interest. Rehabilitation solutions applied worldwide, range from simple relief restoration and planting to more sophisticated site exploitation in order to serve specific social needs. The elaboration of rational rehabilitation plans for every site presupposes deep knowledge and comparative evaluation of all the parameters of the problem. In this paper, a methodological approach of rehabilitation solutions for abandoned quarry sites is elaborated, based on domestic and international experience and practice. Solutions are grouped in eight main categories. In every category the framework of prerequisites and confinements (environmental, technical, social, economic, legal) for their application in Greek quarry site is investigated. A comparative assessment of alternative restoration solutions is introduced, using tools supplied by environmental economics, cost-benefit analysis, G.I.S. and multi-criteria analysis and follows in two stages: 1) Establishment of a set of criteria aiming at a priority list for a number of quarry sites located in a geographical or administrative district. 2) Assessment of alternative solutions for every single quarry from the previous priority list for the selection of the most adequate using technical, economical, social and environmental criteria.

Jan 1, 2008

Water and wind erosion of toxic zinc and lead smelter waste is one of the most urgent environmental problems to be solved in the Silesia region of Poland. Over 87 x 106 Mg of various mining wastes were disposed of in uncontrolled piles leading to soil, water, and air pollution in highly populated areas. Welz and Doerschel process Pb/Zn smelter wastes were stabilized in the summer of 1994 by application of heavy loads of CaCO3 (30 Mg/ha), CaO (1.5 -15 Mg/ha), and municipal biosolids (150 -300 Mg/ha), followed by seeding with a mixture of acid-and salt-tolerant grass species selected in a pot experiment. Vegetation was successfully established on 85% of the Welz material demonstration plot area (0.5 ha), even though it was initially high in water-soluble Zn, Pb, and Cd ranging from 0.4 to 1311,0.1 to 5.8, and 0.05 to 55 mg/kg, respectively. Standing biomass averaged 3.3 Mg/ha on the stabilized Welz waste zone by the end of the third growing season (1997). The revegetation of much of the Doerschel material area failed initially because of extremely high salinity (16 dS m-1), high content of water soluble metals (Cd in particular), and heavy compaction. The area was capped (15 cm) with waste lime and retreated with bio-solids (300 Mg/ha) in 1995, and standing biomass averaged 2.9 Mg/ha in the fall of 1997. The observed plant response to bio-solids and lime indicates this approach to be an environmentally beneficial technology as compared to the traditional methods utilizing topsoil covers.

Jan 1, 1999

By S. J. Zagula

Improved desulfurization of Illinois coals is a widely Shared research goal. The development of a physical cleaning strategy and the results of a project to demonstrate technical and economic feasibility of producing a low sulfur compliance coal from the Illinois Basin are reported. Processing flowsheets to extend or retrofit existing preparation plants are considered. Comminution, conventional and micro-bubble flotation, and selective agglomeration technologies were investigated to maximize pyrite rejection while maintaining high product yield. Batch bench scale testing was followed by continuous pilot plant studies. Parameters included grind size, flow rates, pulp density, aeration, agitation, and reagent dose. An economic evaluation of targeted processes is included.

Jan 1, 1987

By Chuang Sun, Feng Luo, Guo‑dong Li, Xue‑qing Li, Tuan He

The mining-induced failure of the coal seam floor is essential for water inrush. The mining disturbance to the floor, especially in the thick coal seam, is severe, and the water inrush risk is also higher than that in regular thick coal seam excavation. The superposition of many stresses, including in situ stress, mining-induced stress, and confined water pressure, must be considered in the prediction of the floor failure depth. This study adopted the elasticity analysis, FLAC3D numerical simulation, and on-site acoustic wave test comprehensively. The thick coal seam working face of the Zhong-Yu coal mine affected by confined water was selected as the engineering background to study the characteristics of the floor failure. Based on elastic foundation theory and the superposition principle, the mechanical model and the failure depth criterion of the floor were established, respectively. The distribution and evolution of mining-induced stress and the plastic zone in surrounding rock during the mining process are obtained by FLAC3D. In addition, the changes in the P-wave wave velocity in the floor before and after mining were compared and studied by the acoustic wave test method. The range of floor damage depth is determined on the basis of the above research.

Jun 8, 2022

By Sam Lo Grasso, Carlos Herranz Calvo, Stuart Warren, Ted Giesing, Charles Marchesano

Mott MacDonald and Project Management Advisors are providing Technical and Project Management services for San Diego County for the Courthouse Commons Project. The Courthouse Commons Project involves the redevelopment of three downtown blocks owned by San Diego County and construction of an Inmate Transfer Tunnel between the County Central Jail and the San Diego Central Court. The tunnel will be 327 feet long, crosses the San Diego Fault and is being constructed using the Sequential Excavation Method (SEM). This paper discusses the history and procure‑ ment strategy for the project, the technical aspects of the transfer tunnel and the con‑ struction progress of the tunnel to date.

Jun 13, 2021

By J. A. Meech

An analysis of screen design options on the operating efficiency of secondary crushing plants has been conducted using a dynamic computer model. The model allows for the simulation of a wide variety of crushing circuits and can be run on either a microcomputer (IBM PC/XT) or a large time-sharing mainframe computer. Size reduction and separation characteristics of crushers and screens are based on standard manufacturer design and performance data. Input/output routines are available in tabular, alarm or strip chart recorder modes to facilitate operation of the program. A number of alternate circuit designs are compared to show the influence of surge capacity, screen size and area, screen deck location, and closed side crusher settings on the operation of a 10,000 ton per day plant. The program is currently in use at Queen's University to teach plant operations and control. It has potential to be a valuable tool for operator training.

Jan 1, 1985

By Richard E. Ray

Conventional concrete block plastered with a cemantitious coating is the most common material used in the construction of perma¬nent stoppings to direct airflow in underground mines in the U.S.A. All mines experience various degrees of strata convergence depending upon depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting in significant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overhead to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating "Max-Seal" polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased several-fold in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

Jan 1, 1984

By Richard Addison

Rosario Dominicana, S. A. operates an 8,500 tonne per dayopen pit gold/silver mine in the Dominican Republic on the Caribbean island of Hispaniola. The mine is located in an agricultural area which is also an earthquake and heavy rainfall zone. In the 64 years from 1910 to 1974 there were 19 earthquakes within 300 km of the mine in the range of 6 to 8 on the Richter scale and the most recent earthquake in this range occurred in March, 1979. Average annual rainfall in the area is 1.7 m and is distributed throughout the year. Safe and environmentally sound tailings disposal in such conditIons has demanded the buiIding of an extremely strong dam wall and use of a fail-safe system of tailings disposal and solution reclaim. The type of dam, the system of tailings disposal and solution reclaim comprise an interesting example of the manner of handling tailings for a medium tonnage mine. The system is relatively costly but does assure a long-term, safe and trouble free structure and operating system. General views of the dam wall and tailings pond are shown in Figures l through 4.

Jan 1, 1980

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