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By Thomas E. McNider

Preliminary studies were conducted at Jim Walter Resources, Inc. Blue Creek No. 3 Mine to determine the influence propane operated heaters exert on the mine ventilation system when two of three intake airshafts were heated. During initial use of the heaters, it was found that change in density caused by heating a portion of the air at two of three intake shafts altered under- ground air flow changes sufficient to be considered a violation of Part 75.322 of the Federal Coal Mine Health and Safety Act of 1969 as amended by Public Law 95.164. The primary concern was to accurately define the problem in order to derive a workable solution.

Jan 1, 1980

By Nicholas Kyriazia, John P. Shubilla

A performance study of oxygen self-rescuers of varying durations from the United States and other countries was undertaken as an assessment of present worldwide technology. The apparatus were tested on a Breathing and Metabolic Simulator in the Life Support laboratories of the Bureau's Pitts- burgh Research Center. Parameters monitored during the testing were inhaled levels of C02, 02, inhaled gas temperature, and breathing resistance. The metabolic demand placed on the apparatus represented the average demand of the 50th percentile miner performing a 60-min man-test 4, as described in 30 CFR 11H. Results presented include apparatus service life and subjective comments as well as averages and peaks of monitored parameters.

Jan 1, 1986

By P. C. Rath, K. Srinivasa Rao, T. Subbaiah

A process for the recovery of nickel from ammoniacal leach liquor through an integrated solvent extraction-electrowinning (SX-EW) flowsheet was tested on a pilot-plant scale. The objectives of the test run were to assess the reproducibility of laboratory-scale data in a large-scale continuous operation and to study the build up of impurities in the system. The pilot-plant test was conducted under operating conditions that were established from the laboratory-scale experiments. Efficiencies of nickel extraction, nickel stripping and ammonia scrubbing were comparable to the laboratory-scale values, whereas the current efficiency during nickel electrolysis was observed to be less than the laboratory-scale values. The electrodeposited nickel contained some cobalt and iron impurities.

Jan 1, 1998

By M. Bidart, V. Sawyer, M. Saunders Macdonald

A number of open pit gold mines in Nevada extract ore from areas that are below the natural groundwater elevations. This necessitates dewatering, which requires a method for the disposal of the extracted water. Some of these open pits extend well below, the water table with dewatering volumes greater than 10,000 gpm (38,000 L/min). Some mines with large volumes of dewatering water have constructed reinfiltration basins to reintroduce the water into the groundwater system at a point some distance from the pits. This paper presents an overview of the state of the art of reinfiltration projects, including the permit process for such projects in Nevada. The paper includes the necessary engineering considerations.

Jan 1, 1997

By F. M. Doyle, Jun Li, Milton E. Wadsworth, E. Peters

The Raman spectroscopic technique was used to study electrochernically oxidized pyrite in-situ. It was found that Raman-active sulfur oxidation products could be detected after a proper potential was applied to the pyrite electrode for a threshold period of time. There existed a minimum potential below which sulfur could not be observed. However, when the applied potential exceeded a certain limit, the intensity of the sulfur spectra decreased. The minimum potential at which sulfur could be observed changed with solution pH. For both acid (pH 2.7) and weak alkaline (pH 9.2) solutions, the minimum potential was 0.8 V/SCE, whereas for neutral (pH 6.5) solutions the value was 0.4 V/SCE. In strong alkaline solutions (pH 12.5) surface sulfur oxidation products could not be detected at any potential.

Jan 1, 1993

By Bob Gordon, Allen Furth, Dan Dobbels

A 4.8 m (16 ft) diameter hard rock tunnel was driven through granite bedrock to create the 1.7 kilometer (1.1 mile) long Hampton McCloy Retention Tunnel for the city of Richmond, Virginia. During the work the tunnel encountered narrow seams of partially decomposed granite that were not self supporting and could be dealt with using ribs and lagging. However, as the tunnel approached the receiving shaft, it encountered a large seam of highly decomposed rock, alluvial deposits and running sand which resulted in soil loss into the machine. As a result of this condition, a jet grouting program was quickly developed to allow the tunneling to continue. This paper will describe the manner in which jet grouting was used to solidify and stabilize the decomposed bedrock, alluvial soils, and running sand to allow the TBM to continue tunneling.

Jan 1, 2003

By Jihong Xue, Jialin Wang, Della Valle Nicola

Experience of Hard Rock TBM excavating soil in Wanjiazhai Yellow River Diversion Project tells us that selection of Hard Rock TBM to excavate soil in case that rock dominates overall length of tunnel, could be a compromise among tunneling speed, cost and quality. Risk of this operation could be greatly reduced with a detailed study of the geomechanical characteristics of the soil and, if the characteristics are suitable, money and time can be saved by using Hard Rock Double Shield TBM.

Jan 1, 2003

By B Faulkner, M. Weinecke

In 1997, Sveciala began a program to develop a process to convert waste tires into valuable commodities. A review of numerous approaches revealed shortcomings that were process related or mechanical related, while some of the approaches emphasized he production of low-value products. A market study revealed that a process that could produce a good grade of carbon black would be economically feasible. This paper discusses the laboratory and pilot-plant development and commercial plant design of such a process.

Jan 1, 2002

By J. B. Ackerman, C. S. Bucans

The Sunshine Mining Co. has recently started up its new silver refinery in Kellogg, ID. The new plant recovers silver anc copper values from a high grade tetrahedrite concentrate using hydro- metallurgical processes. The plant and process are both new and have gone through the initial startup phase during the first six months of 1985. The full scale plant was developed from laboratory test work. While the metallurgy of the process worked as expected, the material handling problems were difficult to over-come. As might be expected, those parts of the plant that represented available technology started up easily, while the parts that represented new technology presented the most difficulty. Topics covered in this paper include: 1) insufficient type and amount of agitation in the leach vessels, 2) discharge of a non- homogeneous slurry from the leach vessels, and 3) problems associated with very low flow rates in slurry lines.

Jan 1, 1987

By Half Zantop

While the Andean belt of Chile contains porphyry copper deposits of considerable economic importance, only one major and several minor deposits of this type have been discovered in neighboring Argentina. There are no obvious geologic reasons for the country's apparent paucity of important porphyry copper deposits. Instead, a lack of exploration because of poor accessibility and past inadequate mining legislation may partly account for this situation. Western Argentina has porphyry copper prospects ranging in age from late Paleozoic to Pliocene. Many of these prospects have host rock and alteration characteristics that are very similar to those of large Chilean deposits. The economic potential of many of these prospects has not been tested adequately by geoehemical, geophysical, or chilling programs. A recently enacted mining promotion law and updated mining code removes some past exploration obstacles in Argentina, and makes in-depth exploration and evaluation of' the county's porphyry copper potential attractive.

Jan 2, 1981

By Frank Ladwig, Stephen Gos

Tailings and/or wastewater generated from gold extraction plants employing cyanida­ tion must often be treated to remove the cyanides and heavy metals for environmental reasons and/or gold extraction inhibition reasons, due to the presence of heavy metals like copper, which have a detrimen­ tal effect during cyanidation. In recent years, the treatment of effluents contain­ ing cyanides and heavy metals has been widely studied, Among chemical treatment methods, the use of hydrogen peroxide has been universally employed as a viable option. However, in some cases, effluents containing high concentrations of heavy metals and/or solids decompose the hydrogen peroxide, an undesirable side reaction. The addition of stabilizers or other peroxygen compounds together with hydrogen peroxide can, however, considerably reduce the rate of decomposition and thus result in detoxi­ fication costs, which are considerably less than the standard detoxification process using hydrogen peroxide. In some cases, the reaction rate can also be increased, resul­ ting in lower investment costs for new detoxification plants. This paper deals with the results of developmental work performed in the recent past and introduces some new processes with the aim of optimizing reagent consumption and costs.

Jan 1, 1992

By R. Norman Holme

Sulfonate promoters and collectors were originally developed as relatively inexpensive anionic collectors to selectively concentrate the iron-bearing minerals in low grade iron ores and to remove iron and other mineral contaminants by flotation in the processing of glass sands, feldspar and other ceramic raw materials. The first reagents produced were effective collectors for such iron oxide minerals as goethite, hematite, limonite, magnetite and siderite. Further development has resulted in additional reagents with a broadened application to the selective flotation of a variety of nonsulfide and nonmetallic minerals. The products in this group are anionic sulfonate-type promoters, natural petroleum sulfonates, and synthetic modified sulfonates. Beyond their applications to iron-bearing minerals, the sulfonate collectors have gained commercial use in the flotation treatment of barite, celestite, fluorite, apatite, chromite, industrial garnet, kyanite, mica, rhodochrosite and cassiterite. in addition, extensive laboratory studies indicate their potential suitability for flotation of the following minerals: Anatase Anhydrite Bauxite Beryl Calcite Chlorite Some Copper Carbonates Corundum Dolomite Hornblende Huebnerite Ilmenite Lepidolite Magnesite Phosphate Minerals Rutile Scheelite Spodumene Sillimanite Talc Tourmaline Wolframite Zircon Sulfonate promoters are water soluble or dispersible liquids, syrups or pastes of varying viscosity with colors ranging from dark blackish-brown to clear. Customarily, they are fed to the conditioner or flotation as 5% to 30% water solutions or dispersions. In addition to their normal collector activity, certain of these products display notable frothing characteristics. Improved collector efficiency and adequate froth control can frequently be obtained by employing mixtures of sulfonate reagents, of ten with results quite markedly superior to those achieved with equivalent dosages of the individual promoter alone. Reagent requirements will vary with the type of mineral being treated; however, a general overall range of 0.13 to 2.0 kg/metric ton (0.25 to 4.0 lb/ton) of feed should cover most applications.

Jan 1, 1986

Controlled-blasting experiments in small development drifts were conducted at CANMET's Experimental Mine in 1992 and 1993. The objective of these experiments was to develop suitable controlled-blasting techniques for small development headings that are drilled by jackleg with 32-mm-diam holes. The experimentation was also aimed at providing insight into blast-damage mechanisms. Particular attention was given to the physical-mechanical properties of the rock and the rock-mass structural data. The drift faces were approximately 2.4 by 2.4 m (7.9 x 7.9 ft) in size with 36 to 43 holes drilled to a depth of 2.4 m (7.9 ft). Cartridged water gels, emulsions and semigelatin dynamite were used in the cuts and as primers, ANFO was used as the main explosive and decoupled 19-mm (0.75 in.) diam semigelatin dynamite charges were used in the perimeter holes. Smooth-blasting techniques and presplitting were tested in the underground mine. All of the blasts were monitored with a multichannel blast-vibration monitor, to which was attached sets of high frequency geophones and accelerometers. These experiments demonstrated the efficiency of controlled-blasting techniques for the reduction of blast damage and also demonstrated the need to improve the safety and efficiency of using explosives.

Jan 1, 1997

By P. C. Cochrane, I. S. Clelland, S. H. E. Phillips

Geological and hydrological conditions in the strata overlying the Salado Formation vary considerably in the Carlsbad, NM, area. The first four shafts sunk at International Minerals and Chemical Corp. (IMC) property have been located in competent and essentially dry conditions, while other shafts on adjacent properties have had such adverse conditions that ground freezing has been chosen as the water and ground control technique for shaft sinking. At the location of the IMC No. 5 shaft there has been extensive erosion and salt dissolution in the Rustler Formation, leading to collapse of some zones of the strata. Both ground freezing and pregrouting were considered as alternative methods of stabilizing the extremely poor ground conditions and controlling the potentially very heavy water inflows. It was decided that pregrouting the shaft was feasible and would offer substantial cost and time saving over a ground freezing technique. This paper describes the pregrouting techniques used and illustrates the requirement for flexibility in a grouting program so that it can be modified to reflect any new or additional information obtained during the progress of the grouting.

Jan 1, 1987

By K. Adam

Improved environmental performance comprises one of the key objectives of the sustainable development in the mining industry. Within this framework, a research project was undertaken by TVX Hellas, a mixed sulphides producer in northern Greece, in order to develop and evaluate anaerobic wetlands as an alternative method for the treatment of acidic waters originating from old mine areas. The anaerobic treatment using organic substrates, aimed to neutralize the acidity of the mine drainage and remove the dissolved metals, such as Fe, Zn, Mn etc., in the form of insoluble compounds retained within the substrate. The effectiveness of this treatment method, as compared with the conventional neutralization techniques with alkaline additives, extensively used in the mining industry, was assessed based on environmental and economic indicators. The indicators applied included contaminant removal, land take per unit of contaminant removed, effluents quality, remediation of past environmental damage, energy and reagents consumption, capital and operating cost. Based on the above, the applicability of anaerobic wetlands for the treatment of acidic streams originating from old mined areas was concluded.

Jan 1, 2003

By Yi Luo

Subsidence events occurred over inactive room and pillar (R&P) mines, including abandoned mines or sealed portions of active mines, are classified as unplanned subsidence because of their timing and distribution are unpredictable. When investigating such subsidence cases, many uncertainties exist and disputes often focused on whether the observed structural damages are caused by mine subsidence or other natural or artificial causes. However, solid evidences to identify the causes are often lacking. In order to conduct a thorough and impartial investigation, good knowledge in subsidence theories a

Jan 1, 2009

By J. K. Mokka, P. D. Rao, H. K. Lin

Extensive exploration has resulted in delineation of a massive sulfide district on the north flank of the east-central Alaska range. The district covers approximately 400 mi2 and contains numerous stratiform, transposed and some replacement type sulfide deposits ranging in size from less than 1 million st to 20 million st. Five types of ores were sampled for the study. Mineralogical analysis revealed that the minerals are too fine grained for conventional grinding and beneficiation. Hydrometallurgical studies were conducted using ferric chloride as a lixiviant. Ore microscopic studies as well as electron microprobe analyses of minerals in the raw samples and leach residues explained the low recoveries for certain elements as well as sources of impurities that need to be eliminated from the process streams.

Jan 1, 1992

By William E. Bedal, Richard S. Kunter

Artech Recovery Systems, Inc has developed a low pressure and temperature chloride leach process called the "Caslumu1 Process" to extract metals from arsenical flue dusts and residues and fix the arsenic in an environmentally stable form as ferric arsenate (scorodite). The process was pilot tested at Hazen Research in an integrated plant including continuous recycle from August 1989 to October 1989 during which several tons of flue dust were processed. Based on this pilot program, the process was deemed technically feasible and produced commercially salable products. Residues from this pilot program were subjected to a long-term stability test jointly designed by Prl environmental services and the USEPA. The process, its versatility, and the nature of the products ls discussed in some detail.

Jan 1, 1992

By W. Hennig

Efforts to define sustainability indicators are continuing in the mineral extracting industry and sector research institutions. Comprehensive ‘sets’ of economic, ecological and social sustainability indicators for the minerals industry are a necessary precondition for rationale-based negotiations with stakeholders from society. These tools alone, however, will not suffice in a delicately balanced economy-ecology -social well-being equilibrium with ever shifting valuation of different variables. Individual interests and emotions and also ideologically motivated positions of diverse stakeholders are gaining momentum. The minerals industry therefore has to develop beyond the rational pro-arguments for mining in the form of sustainability indicators also proactively its ‘soft skills’ to deal with expectations, fears and outright anti-mining bias, if it wants to retain the ‘social licence’ to continue.

Jan 1, 2005

By Cheng Zhengbing, Sun Baoqi

This paper summarizes several chemical purification methods used for producing high-pure industrial minerals These methods, mainly including alkali melting, acid leaching, oxidation-reduction bleaching, are respectively used to eliminate the impurities such as silicates in graphite and diamond, ferric oxides in quartz sand or other valuable silicate minerals, colouring impurities in kaoline, barite and other minerals which are required to have a high-whiteness. The fundamentals of the chemical purification methods and some practical examples in China are introduced in the paper.

Jan 1, 1995