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By Robert C. Gabler

Three filter cloth fabrics commonly used in drains for coal waste embankments were tested by the Bureau of Mines for clogging behavior and deterioration under simulated field conditions. The objective was to provide guidelines for the mining industry for the proper selection and use of filter cloths to assure safer embankments at mine waste disposal sites. The filter cloths were tested with three coal waste samples in stand-pipes used to simulate coal mine waste disposal environments. Two of the cloths showed a tendency to become clogged with fines from the wastes. One waste caused clogging by precipitating an iron-silicon compound on the test cloths. No apparent cloth deterioration resulted from exposures to the simulated coal waste environments. (The exposures ranged from 2 to 12 months.) In other tests, exposures to waters in the pH range of 2 to 12 and to reagents used in coal-preparation plants resulted in insignificant or no deterioration, as measured by tensile strength. However, long exposures to sunlight (ranging from 4.6 to 6 months) caused major deterioration in two of the cloths (86-and 98-pct losses in tensile strength) and slight deterioration in the third cloth (9-pct loss in strength).

Jan 1, 1984

By S. Deonarain, L. S. Schultz

"This paper details the process and methodology followed to rehabilitate a rectangular ventilation shaft, situated in the Free State region of the Witwatersrand Gold Fields in South Africa. The shaft consists of seven compartments where self-mining of the sidewalls had taken place and damage to the decayed steel work in the shaft had taken place, thus limiting access down the shaft. The paper will provide some insight into the successes and challenges encountered during the project and may provide some learnings for future projects of a similar nature. INTRODUCTION The ventilation shaft forms part of the Phakisa Mine, situated in the Welkom area of the Free State province of South Africa, and is located in the Southern part of the Witwatersrand Basin, one of the world’s largest known and richest gold deposits (Figure 1).As is typical in South African gold mines situated in the Witwatersrand basin, the shaft is 1 770 metres deep (below collar). The shaft was sunk during the early 1940’s and comprised a rectangular shape with 7 compartments, used for both rock hoisting and men and material winding, respectively, with a single lift “Mary-Anne” compartment. Early in 2003, the mine decided to change the shaft from a downcast hoisting shaft to an up-cast ventilation shaft. The conveyances, ropes, winders and headgear (head frame) were removed and replaced with a high volume fan delivering 323m³/s of air at a pressure of 4.2Pa on surface. The up-cast velocity in the shaft was 6.5m/s, however this reduced significantly with the scaling of the shaft and the restrictions at shaft bottom. Although Harmony had converted the shaft from a downcast service shaft to an up-cast ventilation shaft some years back, the shaft steel work in the barrel of the shaft was left intact. Over the years, the steelwork in the shaft had decayed (rust and grime) and portions of this steelwork fell down the shaft. Concurrent with the decaying steel work, portions of the shaft lining had collapsed and it was getting progressively worse."

Jan 1, 2019

By Doug Anderson

Blast vibration seismograms are generally collected strictly for compliance with regulations. The peak levels (including dominant frequency) are typically all that are looked at. However, these records contain a lot more information about how a blast has performed. The seismogram is actually a record of explosive energy that was not used in fragmenting rock. The trick is to determine how to extract information that would be useful in analyzing blast performance.

Jan 1, 2013

By Bruington T, Perkins J, Hutton R

Natural resource developments are among the largest and most challenging projects taking place in the world. They involve capital intensive investment with long lead times and the management of geological, market, technical, operational and financial issues. A clear strategy is required to manage these projects and this strategy is underpinned by a development Philosophy.

Jan 1, 1997

By Satu Strömberg

A single-particle laminar-flow technique was used to study oxidation of two nickel concentrates and a granulated nickel matte (43 wt% of Ni). Experimental conditions were: reaction gas from N2 to N2 + 75 vol% O2; gas preheating temperatures ranging from 500 to 1100°C. The major nickel-bearing minerals in the two concentrates were pentlandite and violarite, respectively. Chemical analysis of the particles was used to determine the oxidation degree of the materials, and optical and scanning electron microscopy were used to detect their morphology and mineralogy. Total desulfurization of the nickel concentrates was achieved under the most oxidizing conditions, while the sulfur removal from the nickel matte was not as efficient, especially with the coarse size fraction. Pentlandite-based concentrate was found to be less reactive than the violarite-based.

Jan 1, 1995

By F. W. Lee

The paramount importance of water to life of all forms on the earth is too well known to require elaboration in this brief paper. It has repeatedly been termed the most valuable of all our mineral resources. Its importance is justifiably recognized in the extensive areas covering the earth which receive sufficient rainfall to sustain a relatively luxuriant vegetation; but in those areas where rainfall is insufficient to support anything but a relatively meager plant growth, the location of a water supply and its development become of even more vital interest to those attempting to obtain a living from the soil. Geological investigations concerning the water supply of the United States have been most extensive, important work having been accomplished by Federal, State, and local governments and by private enterprise. A casual examination of the titles of the 739 Water-Supply Papers published by the United States Geological Survey3/ alone testifies 'to the vital nature of our water resources and the extensive work that has been done on them.

Jan 1, 1936

Large GDP increases in the Pacific Rim countries have been accompanied by similarly large increases in demand for oil products. In the case of residual fuels, this demand has been tempered by the substitution of other energy products such as coal or gas. In the region's developing and newly industrialised nations, it has not been possible to make the very large investments in infrastructure which allow other energy sources to be used for transportation. As a result, GDP growth has been mirrored in the demand growth for automotive fuels. Other non-substitutable products such as lubricants have also benefitted by the region's GDP growth.   The combination of a number of years of sustained growth, coupled with increasing quality requirements is now stretching the upgrading capacity of the region's refineries. IT, as seems likely, the region continues to enjoy a high GDP growth rate, then this will be accompanied by increasing reliance on finished products coming out of the Middle East.   The owners of the most simple form of refinery in which crude is simply distilled and the naphtha reformed into petrol will face major capital investments. If they decide not to bear this cost, they will face increasing problems in selling their surplus residual fuel oil at an economic price. Quality will become an increasingly important issue. Not only in the well publicised areas such as unleaded petrol, but also for products such as lubricants which play a major role in the efficiency of modem equipment. Quality of service such as hours of opening, ease of access, and service station facilities will also become increasingly important as the oil companies use these to attract customers and gain brand differentiation.

Jan 1, 1990

By Zhou Shu-cai

"A method has been proposed for the pre-treatment of high phosphorus iron ore by carbothermic reduction assisted with microwave irradiation and magnetic separation on a laboratory scale. Chemical analysis of the reduced ore sample, the metal sample and the slag sample were conducted. Based on the above research, the influences of carbon addition, microwave power and microwave irradiation time on the recovery of Fe and dephosphorization were discussed. It indicated that the increase of microwave irradiation time and power had substantial effect on the recovery of Fe while the influence of carbon addition was not obvious and the highest iron recovery ratio reaches some 95.5% when the dephosphorization ratio was 37.68%. A high iron recovery ratio and a reasonable dephosphorization rate were incompatible under the conditions investigated in this study due to the reduced iron and because unreduced P-contained gangues were not efficiently separated. This method may provide a reference for the future utilisation of high-phosphorus iron ore.IntroductionWith the rapid growth of crude steel production in China, the source of iron ore tends to become increasingly strained and is facing the risks of raw material shortage for the iron and steel industry. In order to decrease the production cost, China has to focus on the utilization of its domestic low grade iron ores for the iron and steel plants [1-2]. China has a large deposit of high phosphorous iron ore with a reserve of 7.45 billion tons which is unused in any large scale [3]. Therefore, the development of a successful and economically viable technology for high phosphorus iron ore is of profound importance. To remove phosphorus from the high phosphorus iron ore, several mineral and metallurgical processes have been proposed, such as bio-leaching [4], roasting reduction plus melting separation [5], pre-reduction and screening methods combined with mechanical crushing or air jet milling[6] selective agglomeration plus reverse flotation [7]. However these processes are not cost effective or are time consuming. The traditional pyrometallurgical process( BF+ BOF) refuse this kind of ore mainly because that molten iron is saturated with carbon or high carbon content and thus all phosphor us in the burden goes to the molten iron[8]. Therefore, it is important to exploit the cheap and abundant high phosphorus iron ore as a resource in ironmaking. In recent years, the microwave was widely introduced as a heat resource for extractive metallurgy of iron ore or other minerals. For example, microwave assisted ore milling, microwave assisted carbothermic reduction of metal oxides and microwave assisted mineral leaching issues[9-10]"

Jan 1, 2014

By Patricia R. Devine

This report expands an earlier study by Jack Faucett Associates (OFR #40-88) of the same title. Both reports are based upon an interindustry analysis from 1963 through 1982, during which time U.S. metals consumption and production did not keep pace with economic growth. The report discusses three sources of change: technological change, economic growth, and composition of final demand, as well as the relative importance of the individual components of final demand for metals. The results show investment and personal consumption to be the most metal-intensive components of final demand, and technological change to be the major cause of decline in consumption growth during the study period. Technology change is defined as alterations in production processes resulting in more or less consumption of metal per unit of output, often because of material substitutions and design changes. A trade analysis shows the significance of import growth, particularly indirect imports (metal contained in imported goods) as a factor contributing to the reduced growth rate of domestic metal production. The effect of import growth is partially offset by indirect export growth, suggesting that continued increase of all U.S. exports can have a strong effect in reducing the negative trade balance in metals.

Jan 1, 1988

By James L. Elder, J. P. Capp, James J. Dowd

The Bureau of Mines and the Alabama Power Co., jointly, conducted the first experiment undertaken in the United States in underground gasification of coal in place, at Gorgas, Ala. Milton H. Fies, manager of coal operations, Alabama Power Co., proposed the cooperative investigation to Arno C. Fieldner, chief, Fuels and Explosives Branch, Bureau of Mines; and assisted in supervising the experiment. The objectives of the experiment were to determine whether coal in place could be burned successfully and whether the burning could be controlled; the effect of the fire on the coal bed and the overlying strata; and the yield and quality of gas that could be obtained.

Aug 1, 1947

By Rainer Kahrger

During the last decade, advances were made in solvent extraction/electrowinning (SX/EW) technologies. Combined with heap leaching, these technologies made it viable to exploit large, low-grade oxide copper deposits. The El Abra Mine is a good example for such a deposit. The deposit is situated in northern Chile at an elevation of about 4,000 m (14,000ft), 70 km (45 miles) north of Calama. Codelco sold 51% of the El Abra to Cyprus Minerals in June 1994, with Codelco retaining the balance. In 1993, Cyprus and the engineer on the project began discussions withinternational companies regarding the materials-handling system requiredfor the project. These early discussions were considered critical for this fast-track project.

Jan 1, 1996

By L. A. Morley

Volume IV of the final report examines the problem of indirect contact of overhead high-voltage power lines by mining personnel. This refers to the contact of energized lines by workers through some intermediate conductor such as a metallic tool or a piece of high-reaching mobile equipment, thus the term "indirect contact." The shock hazard presented by such contact has been a major cause of electrical fatalities associated with mining operations. The report volume is divided into three major areas. The first gives a general background of overhead lines, basic characteristics, and associated hazards, and continues to describe presently used techniques and devices which attempt to alleviate the contact problem. The second area narrows the discussion to the mining industry by presenting a detailed analysis of 39 overhead-line contact accidents in mining since 1970. The third major section uses the information from the first two areas to formulate recommendations to prevent these accidents and subsequent electrocutions at mining operations.

Jan 1, 1982

By Bengt H. Fellenius

"ABSTRACTAn example from a guidelines document for the Eurocode is discussed that addresses design for geotechnical strength of piled foundations in settling soil, generating drag force and downdrag. A modified example of geotechnical response is then analyzed in a failure mode, Ultimate Limit States (ULS), and stationary long-term state, Serviceable Limit States (SLS). It is shown that the Eurocode principles, when applied to correctly determined forces, results in an irrational and costly design. The results of the analysis of the modified example are applied to eight different codes pertaining to piled foundations from USA, Canada, Europe, and other countries. Several of the codes require that the drag force be included as a load in a ULS design, which an absurd and costly requirement, in some codes, in one case made even worse by combining drag force with live load. A major weakness of almost all codes is their minimal treatment and sometimes total absence of aspects of settlement of piled foundation. In contrast, my main argument is that design for capacity, whether in working stress approach, or by LFRD or ULS approaches, is not always safe unless a thorough settlement analysis shows that the design also meets the requirements of the SLS.1. INTRODUCTIONFirst, there were analysis, design, and construction establishing a State-of-Practice, SOP. Then, came codes and specifications summarizing the SOP, as interpreted by a committee. When the state-of-art, SOA, was not understood by that SOP-interpreting committee, the codes and specifications are uneconomical and, sometimes, also unsafe.The paper first presents an example quoted from two commentaries on the Eurocode 7 on design for geotechnical strength by the Eurocode (1997). The example is then modified to a more realistic case and analyzed in failure mode (ultimate limit states, ULS) and in the context of settlement (serviceability limit states, SLS). The analysis results are then applied to eight codes addressing piled foundation design and changes necessary for the referenced codes and specifications to be closer to the SOA are identified."

Jan 1, 2014

By Tom Snyder, John Brulia

PART 3 – UN Identifi cation Markings for the Highway Transportation in Commerce of Bulk Explosives, Oxidizers, and Combustible Liquids

Jan 1, 2015

By Diane Jones, Jeremy Spearman, Tom Matthewson

Requirements for minerals are on the increase globally and the deep sea offers a potential source of essential materials. Extracting these minerals from what is considered an environmentally sensitive area, and one about which little is still known, is a challenging activity, which needs careful consideration and an appropriate environmental impact assessment to be carried out. Extraction of material from the deep sea beds can cause disturbance or damage to benthic communities; impact on mobile marine species such as fish, mammals and reptiles; cause increases in suspended sediment and sediment deposition onto potentially sensitive areas or potentially release contaminants which were previously bound to the sediment. This paper discusses the potential environmental issues surrounding extraction of deep-sea deposits using aggregate dredging techniques and how those issues can be appropriately assessed. In particular issues of suspended sediments, plume transport, water and sediment quality and underwater noise impacts on potentially sensitive species and habitats will be explored.

Sep 1, 2014

About 15 per cent of total electricity (400 MkW) was generated by nuclear power plants in the world (2009) and about 36 000 tons of uranium has been mined in uranium mines annually. Radioactive waste material is produced from uranium mines and nuclear power plants. The wastes must be disposed or stored safely for long-term. If they leak and/or move from disposal or storage sites due to air/groundwater flow, then a serious environmental pollution can occur. Hence, multi-layer system has been proposed and employed in order to seal off these radioactive waste materials from biosphere. Basically, bentonite is now used for establishing absorbing and sealing layers in this system. However, the amount of high quality betonite is very limited and in some cases it is hard to be obtained.On the other hand, a great deal of refuse from coal burning plants is produced every year and the amount of it is expected to be higher each year, especially in developing countries. More than half of flyash is utilised and the remaining is disposed at the disposal sites. However, the life of the disposal site is limited and it is diff cult to find a new disposal site. It is requested that the percentage of the utilisation of the flyash be increased in every field.From the above two points of view, a flyash-based barrier layer/cover system is considered in this research and this paper discusses the applicability of flyash as a content of barrier layer/cover material based on the results of a series of laboratory tests.

Dec 6, 2010

By A. Mazhary

"Although ore sorting in mining is not a new concept, sensor-based sorting has failed to gain broad acceptance due to perceived challenges with the technology. In order to gain wider applications, this research focuses on treating waste rock and low-grade ore to identify and test appropriate sensors and to evaluate the response. Results showed that amenability of rocks to sensor-based ore sorting is both sensor and ore specific. It was also observed that the efficiency (recovery) of sorting is directly influenced by the degree of heterogeneity of the rocks. The overall outcome showed that with the right sensor, several of the materials tested are amenable to sensor-based ore sorting. Mining companies could benefit from multiple economic and design impacts, such as lower energy cost, lower transportation costs, higher metal recoveries and smaller footprints that lead to more sustainable mining. This paper will focus on the effects of heterogeneity of rocks on sorting potential and efficiency.IntroductionSensor-based ore sorting has been attracting more attention since the pressure for effective resource extraction and management has increased. An urge to make most of the current deposits, and to make the low-grade deposits economic to mine has ushered the technology to find new ways to overcome the new challenges. No matter the terminology used, such as coarse beneificiation, waste rejection, particle or bulk sorting, the purpose of sensor-based ore sorting is to remove low-grade rocks before the comminution circuit, increasing the feed head grade and quality while reducing the energy costs related to comminution.Despite nominal advantages, there have always been some concerns that have impeded the intorduction and acceptance of the technology. One of the most important shortcomings of ore sorting is their capability, or capacity, to keep up with the high-tonnage mining. Some other issues that have been mentioned as drawbacks to sorting include installation cost of such devices, feed preparation for effiecient sorting along with accuracy of sorting and probability of false negatives (Manouchehri, 2003)."

Jan 1, 2015

By William R. Nash

The scope of work for the fast track construction of the Weeks Island Replacement Facility, Weeks Island, Louisiana included the design and construction of two salt mines. Mine #1 - An interim underground mining level consisting of a 975 m (3200 ft) incline and 3520 m of 5.5 m x 7.3 m (11560 ft of 18 ft x 24 ft) drill and blast excavation; raise boring; core drilling; roadheader excavation; complete bulk material handling facilities utilizing an existing production shaft. Mine #2 - Simultaneous with the interim mine construction a new one million ton per year underground salt mine was constructed consisting of: two 5.5 m diameter x 381 m (18 ft diameter x 1250 ft) deep shafts; 76450 cu m (100,000 cu yd) of drill and blast bottom excavation; surface and undergound bulk material handling systems (conveyors, skip loaders, shaft equipment, hoisting); ground freezing for water control for both the production and service shafts; the design of the first underground doublewall slipform installation of a dynamic bitumen shaft lining system; the emergency grouting of both the existing production shaft and the interim mining level in the salt dome; 227 mt x 64 m (250 ton x 210 ft) high structural steel production headframe; 2.2 MW (3000 hp) double drum mine hoist; service shaft headframe; and service buildings.

Jan 1, 1987

By Madgwick J. C

Leaching column techniques and microbiological methods have been described in detail in Madgwick and Ralph (1980) and Madgwick, Ralph and Sadler (1981).Sixty-nine kilograms of copper porphyry ore (0.4 per cent Cu, 2.7 per cent Fe) (particle size 2.4-11.2 mm; 60 The effect of sodium chloride (O.6M) irrigation on bacterial leaching of Bougainville copper porphyry ore was studied.Viability of suspended Thiobacillus ferrooxidants was reduced to less than 10 cells/ml in NaCI (O.6M) compared with 10' eells/ml in dilute II,SO, (0.01 M, pll 2). Salt irrigation had no significant effect on heterotrophic and sulphur oxidizing bacteria. Increascd short term recovery of copper (145 g/tonne/ 15 days) was followed by a marked decrease in tenors to less than 20 mg/litre/day compared with an acid leach, steady release, of 110 mg/litre/day. Resumption of acid leaching restored average solution copper to 46 mg/litre/day and the viability of suspended T Ierrooxidates to 10 cells/ml.Quantitative removal of sodium ehloride from ore particles was difficult and t races of NaCI remained for more than 200 days.

Jan 1, 1982

By Charles Knilans, Tassos Grammatikopoulos, Nicole Hoffmann

"Twin Metals Minnesota LLC, (TMM) has recently completed a prefeasibility study evaluating the development and operation of an underground copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), and gold (Au) mining project on the Maturi deposit in northeastern Minnesota.The Maturi deposit is a magmatic Cu-Ni-sulphide deposit occurring along the basal contact of the South Kawishiwi intrusion, comprised of heterogeneous troctolites to gabbros forming a tabular body designated the BMZ (basal mineralized zone). These rocks provide the major gangue mineralogy (plagioclase, olivine, and clinopyroxene) with local, minor rock-forming orthopyroxene, biotite, magnetite, and ilmenite. Altered silicates exist within local fracture and/or alteration zones, which are commonly associated with minor faults in the regional area. The Maturi deposit is comprised of four main mineralized zones within the BMZ, referred to as Stage 1, Stage 2 (S2), Stage 3 (S3), and Upper Heterogeneous. Chalcopyrite, cubanite, pentlandite, and pyrrhotite are mainly hosted within the S2 and S3 units, with talnakhite frequently occurring within the S3 unit.A cross-discipline approach combining geology, geochemistry, metallurgy, QEMSCAN™ mineralogy, and mine planning has been implemented to develop a preliminary geometallurgical model and life of mine metallurgical performance forecast. This paper provides an overview of the methods that were used to develop the model and forecast, and discusses the advantages of such a model in project development and evaluation.INTRODUCTIONThe TMM Project proposes mining a copper-nickel-palladium-platinum-gold-silver (Cu-Ni-PGM) magmatic sulphide deposit situated in the Duluth Complex of northeastern Minnesota, USA. The prefeasibility study proposes a 45,000 million tonnes per day mine and concentrator facility to produce two saleable concentrates. The mine will access two separate deposits, Maturi and Maturi Southwest. Saleable concentrates are the final products of the sequential flotation plant where a high grade Cu concentrate is produced followed by a Ni concentrate."

Jan 1, 2015