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By Mikko Ahola

This paper describes recent innovative analyses conducted by the Bureau of Mines to demonstrate the application of the boundary-element method in evaluating the effectiveness of caving chambers or sacrificial entries to relieve the stress conditions initiating cutter roof failure in underground coal mines. The analysis assumes that cutter roof failure results when the shear strength of the roof rock at an entry corner is exceeded by the applied shear stress. The applied shear stress is due to large differences between the horizontal and vertical in situ stresses known to exist in many coal mining districts experiencing cutter roof failure. The results of boundary-element analysis suggest that driving an arched lead entry in advance of adjacent rectangular entries and allowing it to cave significantly reduces the difference between the principal stresses at the corner of the rectangular entry, thereby lowering the maximum shear stress. Slippage of the immediate roof along horizontal bedding planes into the caved entry is shown to further reduce the stress conditions in adjacent entries. Practical applications of this stress control technique to longwall and room-and-pillar mining are discussed.

Jan 1, 1987

By V. T. McLemore

The Wind Mountain (WM) nepheline syenite deposit is part of the alkalic complex in the Cornudas Mountains, which ranges in age from 34.6 ± 1.5 Ma to 36.8 ± 0.6 Ma. The WM deposit consists of a complex, zoned pluton that ranges from syenite porphyry to nepheline syenite porphyry. The WM deposit has potential use for ceramics and dark-colored beverage containers and consists of nepheline, k-feldspar, albite, and varying amounts of other minerals. Analcime also is present locally but must be avoided because it is unsuitable for ceramic and glass. Chemically the deposit consists of 56-63 % SiO2 17-21 % Al2O3 and 4.0-5 % Fe2O3. Although initially iron is high, when the crushed rock is passed through a specialized magnetic separator, the iron content drops to below commercial maximum standards of less than 0.5% Fe2O3. The WM deposit is currently under exploration and testing to determine marketability.

Jan 1, 1994

By C. H. Brehaut, W. N. Taylor, R. S. Douglas, H. A. Shannon

THE name for this new method of mining is derived from a composition of Horizontal, Radial, Diamond, and the drilling is from raises. This method, worked out at Copper Mountain, B.C., is believed to be distinct in many features from other known methods. GEOLOGY The ore deposits of Copper Mountain are related to the Copper Mountain stock, which is an ideal example of the magmatic differentiation in that it grades from a basic gabbro at the border to an almost pure orthoclase-pegmatite core. The "contact" ore bodies lie along the contact of the gabbro and an older complex of volcanics and sediment termed the "Wolfe Creek" formation. These older rocks, collectively referred to as greenstone, had been fractured prior to the intrusion of the stock and were highly metamorphosed during the intrusion. The "outlying" ore bodies are somewhat different in character, though a similar structural pattern prevails. It is believed that a deep-seated magma of which the Copper Mountain stock is a part has given off solutions that caused a partial granitization of some of the volcanics. Mining problems are caused further by the presence of a series of soft barren dikes intersecting a great many of the ore bodies, which are about 30 ft. wide, strike north-south, and dip at a high angle to the east; and are further increased by the presence of four major faults, with a great many minor faults running at acute angles from them. Fault zones average 8 ft. in width, and consist of gouge and breccia. They strike northeast and dip steeply to the northwest. The faults cut through the ore zones and the dikes, and continue on into the gabbro. The general mine structure with two types of ore bodies, bounded by weak walls and intersected by several series of soft barren dikes and major faults, indicated that a method of mining should be devised that would remove the ore at low cost with the least disturbance of the waste walls and dikes. THEORETICAL ESTIMATE OF STOPING WITH THE DIAMOND DRILL After consideration of various methods, the most suitable one appeared to be horizontal drilling to break the ore in a manner similar to shrinkage stoping. Drilling vertical holes or rings from a bench and breaking to an open slot was eliminated because the weak walls of ore, dike or waste would not permit this type of opening. It was then decided to drill either horizontal radial holes from a raise or parallel holes from a slot cut across the ore body. After discussion, the latter method was believed unsuitable, for the following reasons:

Jan 1, 1945

By S. Agatzini-Leonardou

The objective of this work was to prove repeated loading capacities and investigate the selectivity of physically stabilized algal biomass from Spirulina platensis and Chlorella sp. for the removal and recovery of cobalt, nickel and chromium from laterite heap leach liquors. The testwork was carried out on a bench scale in small glass columns and proved that it was possible to immobilize the biomass on the highly porous surface of pumice stone (kissiris). Nickel and cobalt could be removed from pure aqueous solutions of each metal by the immobilized cyanobacterial biomass. Nickel and also cobalt biosorption was sensitive to the initial solution pH. Cobalt recoveries up to 80% were achieved after 5 loading cycles, from low concentration solutions, at pH 6.0. Nickel removal was complete under the same conditions, whereas chromium sorption was ineffective. Desorption of the metal loaded columns was effected by dilute sulfuric acid. The algal species giving the best adsorption capacities for the metals under consideration was selected for further experimental work with real laterite heap leach solution produced by column leaching. A statistical analysis of all obtained results was conducted using the fraction of metal removed as response. The ratio "mass of metal removed to mass of protein contained in the immobilized cells" was determined as well. The described method might be applicable for recovery of cobalt and nickel from diluted laterite heap leach solutions, such as heap wash waters, or for their removal from waste streams of a hydrometallurgical extraction process.

Jan 1, 1997

By P Carrasco, E Me, M Campos, J Tapia

Correct sampling practices are of vital importance to the mining industry; key decisions for the business are made on the basis of samples in all the value chain. Geology plays a relevant role in pre- and post-investment stages. Actually the understanding of natural variability is essential for geological modelling, geometallurgical modelling, mine planning, grade and process control. Improper sampling practices obstruct this objective introducing irrelevant variability components, which can cause monumental economic losses. A good approach to accomplish this understanding is the application of heterogeneity and IngamellsÆs tests, which are useful tools to quantify the variability of a certain well-delimited geological unit at different comminution scales. The application of heterogeneity test can help minimise Pierre GyÆs fundamental sampling error and to study the impact of other sampling errors. IngamellÆs test allows us to define the correct mass of sample for chemical analysis. This paper presents the results of several heterogeneity and IngamellsÆs tests done in Chilean porphyry copper deposits that belong to CODELCO Chile (Chuquicamata, Mina Sur, Radomiro Tomic, El Salvador, Andina and Teniente), in different geological units (endogenous oxides, exotic oxides, supergene sulfides and hypogene sulfides) and for several elements (Cut, Cus, Mo and As). These tests, considering the natural variability, have helped us develop accurate sampling protocols to minimise the fundamental error to acceptable levels. A major contribution of these tests (more than 30) is the generation of secure sampling protocols using the highest sampling constant obtained in the tests, for new porphyry copper deposits that donÆt have information given by heterogeneity and IngamellsÆs tests.

Jan 1, 2005

By Erepan P. C

Flash flotation technology was introduced by Outokumpu in 1985. Considerable success was achieved in other plants with similar operations to OTML. Conclusions from site visits and amenability tests performed on plant samples were that the OTML

Jan 1, 1997

By Connell JE

The Worthing Mine near Hallett Cove. 20 km southwest of the cite of Adelaide, belongs to Aus- tralia's first mining era, which took place in South Australia between 1841 and 1851 (Figure 1). Oper- ations began in 1849 only six years after the com- mencement of metal mining in Australia at Glen Osmond. Although not as historically significant as Glen Osmond (1841), or the much larger copper mines of Kapunda (1844) or Burra (1845) its importance lies with its Cornish enginehouse and chimney. The Worthing enginehouse, built in 1851-1852 is the oldest remaining in Australia and certainly the most significant relic of Australia's first mining era. Six other stone enginehouses were built during that period: at Kapunda in 1848 and 1850: at Burra in 1849, 1850 and 1851; and at Tungkillo in 1849. All of these houses have long since dis- appeared although the foundations of one (Kapunda, 1850) still remain. The significance of the Worthing site is enhanced by its magnificant environmental setting in the bare, steep valley of Field River. Currently (1986) the Worthing Mine is the only site within the City of Marion which is on the Register of State Heritage Items. The site is also included in the Classified List of the National Trust of South Australia and on the Register of the National Estate.

Jan 1, 1987

By D. D. Schlepp

There is a continuing debate about the influence of circulating load and classifier efficiency on the capacity of the circuit. Specifically, the effects of preferential classification, bypassed fines, and the sharpness of classification will be examined. Horizontal cyclones have also proven to be very successful in a number of operations but their impact on the circuit capacity has not been clearly defined.

Jan 1, 1990

By M. D. Gerst

The degree to which copper will continue to be in an integral part of the world economy in the future will depend largely on the dynamics of global economic development, the primary and secondary copper resource stock, technological change, and potential environmental constraints. We have characterized the copper cycle of 1994 for all of Earth's regions and for the planet itself (T. Graedel et al., Environmental Science & Technology, 38, 1242-1252, 2004) and recently updated that cycle to year 2000. In this paper, we compare various features of the 1994 and 2000 cycles. The three largest-using regions, Asia, Europe, and North America, all increased their absolute rate of copper use between 1994 and 2000, and all increased the per-capita rate of copper use as well. Globally, the use of copper increased by about 32%, from 11.7 to 15.3 million metric tons, while population increased by only 8%. Various changes are seen in scrap trade, finished products trade, and other parameters of the cycle. We conclude by considering how the rates of technological change and growth in demand, especially in Asia, may influence the copper cycle in the years ahead.

Jan 1, 2007

By Drain P, Dibdin T. R

THE completion of the Linda incline man and supply haft at the Mount Morgan Gold Mining Oompany's mine led to an investigation of the various safety gears in general use in mining shafts. One of these gears completely fulfilled the necessaryconditions. This paper endeavours to give a description of the man car and safety gears now operating in the before mentioned shaft, together with the main considerations leading to their design and sub equent adoption. Fig 1 diagramatically shows a longitudinal section of this shaft.

Jan 1, 1911

It is no longer adequate in running mines and quarries to simply select the best equipment. Today's competitive international commodity markets demand superior efficiency. This requires efficient production and commercial processes together with systematic involvement of people in continuous improvement of processes. True Total Quality of Management (True TQM) principles provide an operating philosophy for maximising productivity and minimising unit costs of output. Unfortunately, even though these principles are proven in all industry sectors worldwide, they have not always been used correctly. This paper describes basic methodology for correct use of these principles to successfully improve the productivity of rock breakage production processes.

Jan 1, 1995

By GEORGE D. RAMSAY

WHEN the Ironton blast furnace of the Columbia Steel , Co. was first put into operation the iron ore was mined frol11 the deposit near Iron Springs, Utah. This is principally a hematite with 12 to 20 per cent of magnetite finely disseminated throughout the ore. It varies from a fairly soft broken rock structure to that which is hard and compact. In the broken form it will weigh about 150 lb. per cu. ft., and in place the density is approximately 250 lb. per cu. ft. The first ore received for the blast furnace was crushed so as to pass through approximately a 4-in. square opening screen. A typical screen test of this ore is shown in Table 1.

Jan 1, 1935

An Attractive Investment ?Near term low cost and secure PGM producer ?restricted supply legislated demand ?strong pipeline of resource development ?Building Canada?s largest undeveloped PGM-Cu resource ?All work (resource, reserves, DFS, EA) is NI43-101 compliant ?Strong balance sheet: over $8 m in cash with no debt

May 1, 2010

By Wasp E. J

A review is given of recent commercial long distance slurry pipeline systems in- stalled worldwide. The technological advan- ces in slurry engineering and system opera- tion are discussed, together with a brief re- view of the economics of slurry transportation and future trends in the industry.

Jan 1, 1973

By Borshoff J, Coles R

The Rum Jungle Uranium Province is lo cated on the western margin of the Pine Creek Geosyncline approximately 60km south of Darwin. Uranium was discovered in the Embayment area (Whites Deposit) in 1949, spurring active ex- ploration and leading to the discovery of the Rum Jungle Creek South Deposit in 1959. With the discovery of the Alligator Rivers Uranium Field, new criteria in the understanding of the controls for mineralization sparked a re- surgence of exploration activities in the Rum Jungle area. Uranerz Australia Pty. Ltd. (UAL) commenced exploration in the area in the late 1970's in joint venture and in its own right. Two domal Archaean granitic complexes, the Rum Jungle and Waterhouse Complexes, domi- nate the area. They are unconformably mantled by Lower Proterozoic sediments metamorphosed to middle to upper greenschist grade. The Lower Proterozoic sediments are unconformably over- lain by remnant blocks of Carpentarian sand- stone, generally preserved in downfaulted blocks. Over a six year period extensive geolo- gical, geochemical and geophysical programs were conducted to reinvestigate previous target areas and locate new prospective zones. Exten- sive shallow bedrock drilling showed that lo- cally the stratigraphic succession is quite variable and cannot always be divided into an ordered succession for correlation with groups and formations established by the Bureau of Mineral Resources (BMR). Deformational events resulting in intraformational recumbent folding and overthrusting also account for repetition of certain lithotypes.

Jan 1, 1984

By Miller JD, Ye Y

The Air-Sparged Hydrocyclone (ASH) has been developed for the fast and efficient flotation of fine mineral particles in a centrifugal field during the past decade at the University of Utah. Over the years, the air-sparged hydrocyclone unit has shown promising potential for the flotation of copper porphyry ore, low-grade placer gold and auriferous pyrite ores, various industrial minerals, and fine coal cleaning. Many fundamental studies including the X-ray computed tomography (CT) analysis have been carried out in order to understand the multiphase fluid flow phenomena associated with ASH flotation. With data available from these studies, it is now possible to construct more accurate ASH flotation models for different applications in order to analyse the behaviour of the system and to optimise design and operating variables. The ASH flotation model developed in this paper is based on the data given in `Air-Sparged Hydrocyclone/Advanced Froth Flotation Fine Coal Cleaning', Final Report, DOE Contract No DE-AC-88PC88853, submitted by Pennsylvania Electric Company (PENELEC), December 1989. Data from several hundred experiments with the two-inch ASH-2C air-sparged hydrocyclone (capacity 0.1 - 0.3 tph dry coal) are available from the report and have been used for this analysis. In the past, a preliminary model based on limited data had been developed. The current study, however, emphasises the global behaviour of the ASH system by utilising almost all the data from the report for the purpose of scale-up and industrial application. There are two parts in the current modeling and analysis effort for ASH flotation of fine coal. The first part is the modeling/analysis of dimensionless ratio of overflow opening area to underflow opening area, A*, and the dimensionless ratio of air flowrate to slurry flowrate, Q . The second part involves the modelling/analysis of all other variables in the system and an expert system for operation and control is introduced.

Jan 1, 1993

By Yuki Tsunazawa, Shuji Owada, Sho Fukui, Chiharu Tokoro

"Since the amount of e-waste has been rapidly increasing all over the world, there is a desire to develop the effective recycling process. E-waste has various kinds of electronic components with valuable and/or hazardous materials. Recycling of them is an important subject from the viewpoint of both the recovery of valuable materials and waste treatment. In common with all mineral processing, the comminution of e-waste is a key process because the liberation states after comminution determine the overall efficiency of metal recovery. Since some of useful critical metals are concentrated in a specific component, a special and selective grinding is expected to be effective. However, the knowledge about the mechanism and the effectiveness of the selective grinding is still limited and unclear.To better comprehend the mechanism, in this study, the investigation of comminution process using the particle-based simulation was conducted. Especially, this study focused on the comminution performance of printed circuit boards (PCBs), which are major components of e-waste. The behavior of PCBs and airflow in a drum typed agitation mill having flexible chains was simulated by the discrete element method (DEM) coupled with computational fluid dynamics (CFD). To model the shape of PCBs, the particle based rigid body model was introduced into the DEM. Since this model could not directly simulate the breakage phenomena, collision energy was calculated to qualitatively evaluate the comminution performance. In addition, the simulation results were compared with the experimental comminution tests using simulant PCBs where some capacitors were solder-mounted. These results indicated that comminution performance was affected by the rotation speed of the agitator. It was also demonstrated that the comminution performance was qualitatively evaluated using the particle-based simulation and this particle-based simulation made it possible to investigate the mechanism of e-waste comminution."

Jan 1, 2016

By W. M. Weigel

SALT production in Louisiana and Texas at the present time is entirely from salt domes of the interior and coastal groups. Before and during the Civil War salt was recovered from numerous salines and salt springs by evaporation in open 'kettles. The location of these in nearly every instance was near what is now known to be a salt dome, and the source of the salt in the salines and spring waters was that in the salt core. The tops of many of the shallower domes have been subjected to erosion1. The discovery that the salt occurred as large masses of rock salt in the form of domes was made in May, 1802, at Avery Island, La., by John Marsh Avery, grandson of the original owner, John C. Marsh, who built the old salt works in 18122. The first shaft for mining was sunk on the Avery dome in 1867 by Chouteau and Price. It was 90 ft. deep, about 58 ft. being in solid salt. It was abandoned in 1870. There are three general groups or fields of salt domes; interior Louisiana in northern Louisiana, interior Texas in northeastern Texas, and the coastal domes nearer the Gulf Coast and extending from the Mississippi River to the Rio Grande. This last group contains by far the greatest number of domes. As many of the coastal domes especially are prolific producers of petroleum and a few of sulfur, their geology has been intensively studied and fully covered in the literature. The depth to the top of the salt varies from near the surface, where shallow ground waters have dissolved the salt to just below recent deposits, to several thousand feet, where the depth has been estimated only by geophysical methods. The diameter of the salt core varies from less than ½ mile to over 2 miles. Only domes where the salt is compara-tively near the surface have been developed for commercial salt. Three deeper domes, which will be described later, have recently been developed or are in process of development, as a source of brine for chemical use.

Jan 1, 1935

The high pressure acid leach process (HPAL) is being commercially used in four plants around the world to treat limonitic laterites. The two major operating costs of the HPAL process are the sulphuric acid and the energy required to heat the pulp to the desired temperature (>240°C). As an alternative to acid injection and steam heating, the in-situ generation of sulphuric acid and heat, produced during the high temperature pressure oxidation of sulphur-bearing materials blended with laterites, has been investigated at the laboratory scale. Various sources of sulphur have been examined, in particular, elemental sulphur, pyrrhotite and a Cu-Ni low-grade bulk concentrate. Under the proper blend ratios, all sulphur sources tested generated sufficient acid to result in equivalent nickel and cobalt dissolutions. A significant improvement to the process economics can result from the addition of sulphur sources containing valuable by-products, such as nickellcobalt andlor precious metals (gold and PGMs). This is especially true in the latter case, when the HPAL can be operated under Platsol conditions (i.e. with the addition of 5-10g/L of chloride), to dissolve the base metals and precious metals simultaneously in the autoclave. Various examples of the application of this concept are presented, together with a brief discussion of its implication on the autoclave design and the downstream processes to recover the values from the leach solutions. Keywords: limonite, co-treatment, acid consumption, sulphur, sulphur compounds, pressure acid leach (HPAL, PAL), Platsol process

Jan 1, 2004

By Lung Cheng

Based on earlier tests that showed steel to be much more likely to cause frictional ignition than tungsten carbide, the Bureau of Mines redesigned coal-cutting bits to reduce the hazard of face ignitions. Two bit designs--a mushroom-shaped bit with a conical shank and a dove-tail bit with a rectangular shank--are described, as well as bit wear tests conducted in the laboratory and in an operating coal mine. In laboratory tests, for 1/8-, 1/4-, and 1/2-in-deep cuts and cutting speeds of 280, 500, and 660 ft/min, the mushroom bit had significantly longer tip wear life than the conventional bit; the dovetail bit was also superior to the conventional bit. Results of in-mine tests on the mushroom bit agree well with laboratory results. In-mine tests of the dovetail bit are underway.

Jan 1, 1983