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By Kan Xing

This paper introduces common detrimental consequences to the environment from mining in the Beijing West Mining Area. For example, ongoing mining operations can cause the following environmental deterioration: rock burst, roof rises, roof falls and inrush (Pit dash for ward water). Post-closure, after minerals resources are exhausted, the following environmental issues may remain: landslides (collapse, and mud-rock flow), dropping or exhausted water tables, water pollution, desertification and soil erosion, water accumulation, Slay endanger, ground subsidence, and causal factors in seismic activity. This paper analyzes this wide range of environmental consequences of mining, and offers a theoretical foundation to underpin a corresponding management scheme.

Aug 1, 2013

By I. J. Jansen, C. L. Hooks

Successful soil construction involves prepa¬ration of an adequate base, selection of high quality soil ma¬terials, and placement of those materials by means which will establish a continuous macropore network and modest to low soil strength. Where such has been accomplished, experi¬ments reveal row crop productivity on reclaimed land which is very competitive with that on undisturbed land. Inferior productivity and sensitivity to drought stress are experienced where the soils are excessively compacted during construc¬tion. Some deep tillage practices have been quite successful in improving the compacted soils, but it is preferable to avoid compaction as the soil materials are handled.

Jan 1, 1987

By Yuexin Han, Jie Liu, Shuai Yuan, Yanjun Li

"In order to improve recovery efficiency of iron minerals from iron ore tailings and to reduce its connected environmental pollution, this article investigated the reducing roasting of iron ore tailing in a laboratory fluidized magnetization roasting reactor to optimize the roasting method and conditions. The examined parameters included roasting temperature, roasting time and reducing atmosphere. The parameters evaluating magnetizing roast efficiency and theoretical value were determined. X-ray diffraction (XRD) analysis was used to investigate the conversion of iron phase after roasting. The results show that the best magnetizing roast conditions are roasting temperature of 540?, holding time of 15min, and CO concentration of 20%. The magnetization conversion ratio of roasting products is over 80%, under the best magnetic separation condition, the concentrate grade of iron is 65.61 % and the recovery of iron is 83.77 %. The XRD analysis shows that Fe exists in hematite and siderite before roasting and exists in magnetite after roasting. The technique not only recovers the iron minerals from tailings with good economic benefit, but also reduces the environmental pollution of tailings accumulation.INTRODUCTION Iron ore tailings are the solid wastes generated during the beneficiation process of iron ore concentration and are one of the main pollution concerns in the mining industry (Das et al., 1996). Continuous development of the iron and steel industry has led to the increasing amount of iron ore tailings; there are over 300 million tons of iron ore tailings discharged per year (Rao et al., 2016). The huge amount of stockpiled iron ore tailings brings a series of environmental and social problems. Comprehensive utilization of iron ore tailings can not only reduce environmental load but also conserve resources, promoting sustainable development of the society. In recent years, iron ore tailings as secondary resources have received considerable attention in many countries in the word and numbers of studies on utilization of iron ore tailings were carried out, such as recycling the valuable minerals (Datta et al., 1996; Jia et al., 2013; Panda et al., 2018), used in construction material compositions as alternative source of raw materials (Das et al., 2012; Zhou et al., 2012; Luo et al., 2016) and other utilization. The iron minerals were recovery by magnetization roasting (Rao et al., 2016; Yang et al., 2013; Yang et al., 2011) and flotation (Kumar and Mandre, 2016). By comparison the reduction roasting has more advantages, but it was found that the conventional roasting equipment was inefficient, high energy consumption and un-economically applied on an industrial-scale."

Jan 1, 2018

By Robin Adams

After nearly five years of economic hardship, the world copper industry is, in our opinion, about to enter a period of considerable strength. This opinion is based on three main propositions, namely: 1) there are a number of reasons, both general-economic and industry-specific why copper demand is likely to perform significantly, more strongly in the 1980's than in the 1970's; 2) the virtual cessation of investment in new facilities, especially at the mine level, over the past years makes it physically impossible for capacity to expand as fast as demand in the mid-1980's; and 3) there is much less "excess" inventory available than most analysts believe. If we are correct in these assumptions, then the implication is that copper prices will climb up to, and possibly beyond, the cost-justified price level. Combined with general inflation, this suggests a price in excess of $2/pound by 1985 or roughly treble the 1978 average.

Jan 1, 1979

By Peter Bourke, Marc van Olst, Seppo Ronkainen, Natalie Brown

"Since the early days of flotation, process technicians have known that the speed at which the froth is recovered over the lip of the cell has a very direct and consistent influence on the grade and recovery of the circuit. No plant would deny that, even to this day, one of the most important aspects of a process technician’s job is ensuring that the froth is moving at a desired and controlled speed over the lip. Unfortunately, process technicians cannot watch the froth throughout the entire shift, as there are always a lot of other tasks to do.A considerable amount of work has thus been done to develop a “system” that automatically measures the speed of the froth. This measurement would then be used in simple controllers to emulate the steps taken by the process technician in correcting deviations of the froth speed from its desired level. Many of the earlier attempts to measure speed were ineffective, as they were unable to cope with turbulence on the froth surface. The FrothMasterTM instrument makes use of machine vision technologies to measure the speed of the froth over the lip of a cell at a very high sampling rate. This instrument produces an extremely reliable and accurate measurement of the froth speed (as well as other parameters such as bubble size and froth stability). As we will show, the effectiveness of the speed measurement in controlling the performance of the plant is a testimony to its reliability.Three FrothMasterTM units have recently been installed on the Cadia Hills Gold Mine in New South Wales (Australia). The objectives of this installation were:To control the mass-recovery of two Tank Cells in series on the same level where differences in the hydrostatic head between the two cells result in the cells pulling inconsistently with respect to each other.Control of the concentrate grade (%Copper) from the first rougher.Reduction in the frother consumption in the rougher circuit by monitoring the froth speed.A simple controller was designed to react to disturbances in the same way that human operators react. This was done after consultation with the metallurgists and the process technicians at Cadia. The controller had two functions:Stabilisation: The stabilising controller made use of three manipulated variables (level, frother addition rate and aeration rate) to control the froth speed to a setpoint.Optimisation: The optimising controller adjusted the froth speed setpoint based on deviations of the grade (measured in real-time with an OSA) from a setpoint. The plant metallurgist adjusted the grade setpoint based on information about the ore."

Jan 1, 2001

By Jinsheng Chen

To maintain the stability of longwall tailgate entries, they have to be supported by not only the primary roof support but also the secondary roof support due to the impact of the longwall mining¬induced abutment loads. Depending on the mining condition of a typical coal seam and its distance from the previous panel's gob, the longwall tailgate entry is often reinforced by the secondary roof support in the form of standing supports and/or cable bolts or trusses during longwall retreat, Even though lots of research work has been done to study the behavior of different standing supports in the laboratory. their function and requirements for a typical mining condition are still not fully understood due to lack of field data and correct assumptions about the behavior of the already-bolted entry roof under mining-induced abutment loads. Therefore, the application of the secondary roof support for tailgate entry roof control is still limited to trial and error, which often results in either higher cost for tailgate roof control if the design is too conservative or more production delays due to roof falls in the outby tailgate entry if the design is inadequate. To have a better tailgate roof control with reasonable roof control cost, RAG American Coal, NIOSH, and HeiTech have been conducting a joint research project to monitor actual roof loading, roof deformation, and entry convergence in the tailgate entry of 10 North panel at RAG Emerald mine. The actual roof loading data are used to calibrate and improve the roof control model for longwall tailgate entries, which has been developed by RAG American Coal, and to further reduce the roof control cost for longwall tailgate entries. The authors in this study attempt to discuss the Roof Control Model developed by RAG American Coal. in which some guidelines or important parameters for designing the secondary roof support for longwall tailgate entries are proposed.

Jan 1, 2003

By Víctor Gobitz Colchado

Dentro de la industria minera, el objetivo principal del sostenimiento a una excavación subterránea conlleva un soporte de la masa rocosa. Para tal fin, se utiliza la técnica del concreto lanzado (shotcrete), malla metálica y pernos de roca, puesto que ofrecen versatilidad y capacidad portante. En este sentido, el presente texto describe la importancia de dicha técnica a partir de su estructura, filosofía, dimensionamiento, dosificación, rebote, problemas operativos típicos y formas de medición de pago, así como los resultados de campo de una obra proyectada en una mina de la selva central.

Apr 1, 1991

By Vadym Drozd, Yongzhou Sun, Shah Najiba, Jiuhua Chen, Andriy Durygin

"Phase transitions of the potential hydrogen storage compound, ammonia borane (NH3.BH3), was investigated using Raman spectroscopy and a diamond anvil cell at high pressures up to 9.5 GPa and low temperatures down to 90K. At room temperature, ammonia borane has three phase transitions in this pressure range. Upon cooling, four new phases were discovered through changes in characteristic Raman spectra. This result provides information about the stability of new bonding characteristics of this potential hydrogen storage material at low temperature and high pressure region.IntroductionDevelopment of hydrogen technology requires the safe, efficient and environmental friendly materials for hydrogen storage and hydrides have attracted much attention as hydrogen storage media. Among chemical hydrides, ammonia borane (BH3NH3) stands out due to its high gravimetric and volumetric hydrogen density ' "". Despite high hydrogen content, this compound is very stable. It releases hydrogen in several steps by thermal decomposition in the temperature range of 100°C to 500°C. Direct thermal decomposition also causes toxic borazine emission. Recent research interests on ammonia borane include destabilizing this compound to lower the dehydrogenation temperature with an enhanced hydrogen release rate using different techniques, e.g. the nanoscaffolds'', ionic liquids"" and acid'"" or transition metal catalysts' ""'. As a molecule of ammonia borane consists of protonic (NH) and hydritic (BH) hydrogens bonded by the polarized dative bond, thermal or catalyzed decomposition requires breaking of N-H and B-H bonding. Still now, the detailed information about the bonding characteristics of ammonia borane is not sufficient to understand details about its phases and structures. The development of methods to enhance hydrogen discharge rate from ammonia borane requires a detailed study about the structural and dynamical properties that control the stability and the intermolecular interactions of this material. This study is motivated to investigate the stability of the existing phases and also to explore the existence of any new phases at different temperatures and pressures which may have enhanced hydrogen release and uptake properties."

Jan 1, 2012

By M. W. John, I. D. Matthews

SYNOPSIS This paper describes the process adopted for the recovery of gold from a dump originating from clean-up operations at Durban Roodepoort Deep Gold Mine. The gold-bearing dump material was refractory in nature, not being amenable to cyanidation because of the high level of carbonaceous material present. The laboratory tests on the material involved particle-size and chemical analyses, a mineralogical examination of the material, preliminary tests, and optimization of the process for the treatment of the dump material. The preliminary tests included tests on roasting, flotation, pre-leaching, adsorbent-in-leach, and blinding. Of these options, carbon-in-leach showed the greatest potential. The rate of gold dissolution, the rate of gold adsorption by the carbonaceous material, and the ratio of carbon to pulp were then investigated. It was determined that the ratio of carbon to pulp necessary to yield a reasonable gold recovery resulted in a carbon loading that was not high enough for economic elution and regeneration. A process incorporating washing of the carbon with cold acid between adsorption cycles was tested, and reasonable gold recoveries and carbon loadings were obtained. Durban Roodepoort Deep Gold Mine piloted the conceptualized process and determined that it was economically feasible. Two Browns tanks on site were modified, and an acid-wash tank was installed. The capital outlay for the plant was recovered within some 3 months.

Jan 1, 1990

By W. Drummond

The cooling of smelter gases by air dilution, adiabatic evaporative cooling and indirect heat exchange is discussed with reference to the process, to the subsequent cleaning of the gas. and to the use of the heat extracted from the gas. The method of reducing the effect of acidic sulphide formation on the corrosive properties of the gas and the dust and the development of surface cleaning mechanisms?are discussed. The development of indirect recuperators using air, water or steam cooling, made possible by the control of surface fouling is traced. The application of the modern Waste Heat Boiler to the new sulphide smelting processes is discussed with respect to the natural and forced circulation concepts. Case histories are presented to illustrate mistakes made with respect to designs produced without recourse to sensitivity analysis and without an appreciation of "worst process? conditions".

Jan 1, 1992

By Alan R. Cameron, William Forsyth, Tom H. Kleinel

Because good and bad blasting must be defined in terms of overall mining costs, blast optimization requires combined blasting and costing models. Furthermore, the models must be both accurate and comprehensive. A combined fragmentation and preliminary costing model was developed to investigate alternative blasting strategies.

Jan 1, 1995

By D J. Williams, S Islam

Worldwide production of black coal amounts to about 8 billion tonnes. Perhaps 20% of this annual production is washed to improve its quality, generating perhaps 250 million tonnes of coal tailings annually, generally in the form of a slurry. The coal tailings slurry is typically thickened to about 25% solids by mass prior to disposal to a tailings storage facility (TSF), and hence comprise mostly water (about 85% by volume), plus sand, silt and clay-sized mineral particles and carbonaceous material. While the tailings settle and consolidate on deposition in the storage facility, their high moisture content makes them prone to run-out should the tailings dam fail, and makes rehabilitation of the tailings difficult. Hence, it is important to understand the consolidation and shear strength of coal tailings. Laboratory consolidation testing of coal tailings from a slurry to a soil-like state has been carried out in a purpose-built, large-scale, slurry consolidometer, instrumented with load cells and pore water pressure (PWP) transducers. Laboratory vane shear testing of coal tailings produced at different gravimetric moisture contents has also been carried out. The test results have allowed a regression model to be developed relating the peak vane shear strength of the coal tailings to their gravimetric moisture content.CITATION:Islam, S and Williams, D J, 2018. Consolidation and shear strength of coal tailings slurries, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 62–71 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Sjaw WJ

Conditional simulation is a set of geostatistical tools that is becoming popular as powerful personal computers make the use of these tools less costly. The more familiar set of tools for spatial estimation has a number of varieties (eg Ordinary Kriging, Simple Kriging, Multiple Indicator Kriging, etc) each suited to particular solutions of the problem of estimation, for example predicting the average grades of blocks in a region from more or less sparse data. Similarly, conditional simulation has a number of varieties, discussed in this paper, which in various ways address the problem of characterising the variability of a deposit between the known data locations.Conditional simulation can provide a number of equiprobable images of a deposit, at a finer resolution than would be economic or practical to sample, and that can be constrained by various criteria (which may be geological, statistical and geostatistical), to ensure that the images reasonably represent the deposit. These images can then be used to assess the risk involved in various practical mining decisions. Examples are provided where conditional simulation has been used for validating resource estimate parameters, optimising grade control sampling grids, and for ore block optimisation for mining grade control.

Jan 1, 1997

By T. F. Tomb

Past experience has shown that the penetration characteristics of the 10-mm nylon cyclone used on approved personal sampling equipment are significantly different from those determined in the laboratory using a nonpulsating flow source. The Bureau of Mines has developed and recommended a modification to presently approved equipment that will alleviate this difference. However, as a result of this modification, a new relationship for converting respirable dust concentrations measured with approved personal sampling equipment to equivalent concentrations as measured with an MRE instrument will have to be established. This Bureau of Mines report describes the underground sampling program conducted to establish a new factor for converting respirable dust concentrations measured with personal sampling equipment, modified with a recommended pulsation damping device, to an equivalent concentration as measured with an MRE gravimetric dust sampler.

Jan 1, 1973

By S. K. Kawatra, A. K. Bakshi

Mineral suspensions in water show Newtonian flow properties at low percent solids. However, this changes to a non-Newtonian regime as the pet-cent solids increases. For Newtonian fluids, viscosity is independent of shear rate, hut, for non-Newtonian fluids, viscosity varies with shear rate. Therefore, if the slurry is non-Newtonian, attempting to measure the viscosity at a shear rate different from the shear rate experienced by the fluid within the process is futile. This is especially true for a hydrocyclone, where the rate of shear is different at different points within the hydrocyclone. In this case, it is very important to determine the flow type of the suspension before attempting to establish any correlation between the viscosity and the process efficiency. A new technique to distinguish such changes inflow type was developed. This involves two viscometers: a coaxial cylinder-type viscometer that measures apparent viscosity at low shear rates and a vibrating sphere-type viscometer that measures the apparent viscosity at high shear rates. For each of these instruments, special precautions were taken to allow, for the measurement of the viscosity of rapidly settling mineral suspensions. Because the vibrating sphere viscometer is operated at a much higher shear rate than the rotating viscometer, the two instruments together could determine the shear-rate dependency of the viscosity. Ground silica (80% passing 65 µm) in water was used to prepare slurries at concentrations ranging from 10% to 70% (by weight) solids. The viscosity of each slurry sample was measured simultaneously by both viscometers, and the results were compared. With this technique, it was found that all of the silica-slurry samples tested were in the Newtonian flow regime for up to 70% (by weight) solids. Methocel and Cellosize polymer solutions showed clear non-Newtonian behavior using this technique. This confirmed that non-Newtonian behavior of the silica slurries, if present, would have been detected by this arrangement.

Jan 1, 1997

By Xiaoping Xu

An albitization granite type tantalum-niobium ore from Jiangxi Province, China was taken as the research object in this paper. The main valuable minerals in this ore are tantalite-columbite and uranmicrolite, and the minerals that can be comprehensively recovered include cassiterite, sulfide minerals, topaz, zinnwaldite, and quartz-feldspar. Based on the research results of process mineralogy, the roughing process of gravity separation for coarse particles combined with flotation for fine particles is proposed. The combined cleaning process of flotation-gravity-magnetic-electric-hydrometallurgical separation is adopted for the rough concentrate of gravity separation while the combined cleaning process of gravity-flotation- hydrometallurgical separation is adopted for the rough concentrate of flotation. High intensity magnetic separation is used to separate and recover zinnwaldite and quartz-feldspar from gravity tailings. By mineral processing for the crude ore containing (TaNb)cassiterite concentrate is 0.0003% with a grade of Sn 63.22% and a recovery of Sn 47.42% while the yield of sulfide concentrate is 0.0783% with a grade of Pb 33.15% and Zn 27.09% which can be separated to get lead and zinc concentrate respectively. The yield of topaz concentrate is 0.1545% and the topaz mainly distributed in the size range of -0.4+0.074mm, which can be made into abrasive products of different particle sizes after classification. The yield of zinnwaldite concentrate is 16.91% with a grade of Liwhiteness of 75%, which is a glass-ceramic material of good quality. 2O5 0.0346%, Sn 0.04%, Pb 0.10% and Zn 0.33%, the tantalum-niobium concentrate with a yield of 0.00278%,a grade of (TaNb)2O5 53.61% and a recovery of (TaNb)2O5 44.49% is obtained. And the yield of 2O 1.34% and Rb2O 0.40%. The yield of quartz-feldspar concentrate is 30.42% with a grade of K2O+Na2O 8.98% and Fe2O3 0.11% and a natural All of tantalum, niobium, cassiterite, topaz, zinnwaldite, quartz, and feldspar are recovered effectively. Keywords: tantalum-niobium ore, gravity separation for coarse particles, flotation for fine particles, comprehensive recovery

Sep 1, 2012

By T. Mudder

The objectives for closure of a hard rock mine include minimizing long term environmental liability, attaining regulatory compliance, and maintaining geotechnical stability, while closing as cost-effectively as possible. Proper planning for closure should come during the feasibility study, design and permitting phases, and during operations as updates. The lack of a proper or updated closure plan can result in severe environmental and economic consequences. Effective mine closure is the result of a combination of innovative concepts, long-term commitments, and multi-party cooperation. The purpose of this paper is to discuss concepts, commitments, and cooperation as they relate to an effective closure plan.

Jan 1, 1999

By H. E. Peterson

This report revises an earlier publication by the Bureau of Mines on tungsten analytical procedures and expands the coverage by including appropriate procedures for the critical impurity elements that commonly occur in tungsten ores and concentrates (13).3 The basic methods described are not original, but many of the modifications to improve reliability and sensitivity were developed by the Bureau. Gravimetric and colorimetric methods currently used for the determination of tungsten in ores, mill tailings, and concentrates are described. Colorimetric procedures are preferred for low concentrations of tungsten, whereas either procedure is satisfactory for moderate concentrations. Conversely, a gravimetric method is preferred for the determination of tungsten in concentrates.

Jan 1, 1963

By H. Sherman

The general curtailment of activities, so marked in 1931, was continued and intensified in 1932 and although production was maintained at approximately the level of the previous year, 1932 was chiefly characterized by the virtual cessation of drilling in many of the proven fields, a further decline in wildcatting activities, particularly in the Maracaibo Basin, and the relinquishment of large blocks of unfavorably located acreage. A total of only 60 wells was completed during the year of which six were wildcats, while at the same time concessions aggregating approximately. 3,222,000 acres were renounced and reverted to the National Government. The maintenance of production at the previously established level was made possible through the large potential built up by drilling in previous years and by a gradual increase in pumping and gas-lift installations. Towards the end of the year there was a slight but perceptible tendency towards increased drilling in certain of the proven fields. Total production for the year came to 118,076,000 as compared to 118,418,000 bbl. for 1931, while exports amounted to 114,758,000 as against 116,683,000 bbl. in 1931. Table 1 shows production and exports and the average rate per day for the first half of 1932 as compared to the second half. Table 1.—Petroleum Production and Exports in 1932, Venezuela (Barrels of 42 Gallons) Production Rate per Day Export Rate per Day I January-June............ 61,943,000 1 390, 347 July-December.......... 56,133,000 305,071 50,788,000 276,022 Total.........,....... 118,076,000 322,612 114,758,000 313,546 During 1932 the number of active vessels comprising the Lake Maracaibo fleet of shallow-draft tankers was still further reduced, some being temporarily laid up and some transferred to service in other coun-

Jan 1, 1933

HIGH LAKE PROPERTY --HISTORYHISTORY -19501950??s ??Kennarctic Exploration discovers Exploration sulphides (A/B & (D Zones) at High Lake during helicopter reconnaissance exploration program.- -1991 93 Aber signs agreement to earn in to the High Lake Property from Kennecott. 63 holes drilled, primarily testing the known deposits. -2001 Wolfden purchases 100% interest in High Lake from Kennecott and Aber -2002 Wolfden performs helicopter borne TEM Survey over the High Lake Greenstone Belt. -2003 West Zone was discovered following UTEM & Gravity Surveys (performed by Teck Cominco ) over an airborne anomaly approx. 1km west of the known deposits. -2004 Wolfden awarded Bill Dennis Prospector of the Year

May 1, 2006