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By R. Rosenblum, J. Y. Kim, D. Shink, K. G. Stowe

"A small scale continuous flotation cell was designed and constructed at the Noranda Technology Centre to develop a mobile testing flotation circuit located next to the production circuit. This mobile small scale flotation pilot plant can easily and economically be set up at any circuit in a mill and used to evaluate and predict plant performance against a given flotation condition. The main feature of the cell, beside the provisions of automatic pulp level and feed rate control, is to provide a reduced surface to volume ratio approaching to that of an industrial machine.This paper describes the basic design and the results of various testwork carried out to date including aeration, conditioning, reagents, recirculation, flotation gas, etc. are presented in comparison with the plant production results. INTRODUCTIONStudy of the behaviour of an ore during concentration by flotation process starts, in general, with a series of tests in laboratory cells. Given the discontinuous nature of these tests, the information obtained by such a study is somewhat limited. It has long been recognized that laboratory test results are not always reproducible in pilot plant tests and subsequently, the pilot plant results do not always predict plant performance. The differences are often blamed on batch vs continuous operations, grinding media, size distribution, aging (oxidation), water quality, equipment, operator's skills, etc."

Jan 1, 1992

By Wilson D, Kirkland J

Compressed air energy storage (CAES) uses low cost off-peak energy to compress air and pump it into pressurised underground storage. Expanding the air through a modified form of gas turbine generates electrical energy when required. While generating power, a CAES station consumes approximately one-third of the gas required for the equivalent installed capacity of a conventional gas turbine. Air can be stored in underground rock caverns, caverns in salt domes, or in aquifers. Existing CAES power stations use caverns mined out of salt domes. Aquifer storage for CAES has been proposed, but not yet implemented. The groundwater in the aquifer would be displaced during air injection and when required the air would be extracted using the natural hydro-static pressure. Victoria has no salt domes, but has aquifers onshore in the Gippsland Basin with geological dome structures of suitable depth, discovery pressure, porosity, permeability and caprock for CAES development. Field tests costing several million dollars would be required to prove the suitability. The most suitable aquifer is near Seaspray, where several dome structures exist. The aquifer, comprising of coarse sands capped by coal and mudstone, is some 600 metres deep with a hydrostatic pressure of 6.3 MPa. Computer simulation of injection and extraction of air from the aquifer under various combinations of horizontal and vertical wells, permeability and tubing head pressures indicated the largest aquifer structure had the capacity to sustain a 300 MW station. A well field comprising of 24 directionally driven wells with a horizontal exposure to the aquifer would achieve the air flow rates required. Using plant similar to that recently installed at McIntosh Alabama USA, would mean high capital costs compared to standard gas turbine plant. However, a review of modem gas turbines indicated that they could be easily and economically adaptated to CAES duty. Adapting a 120 MW gas turbine would give 344 MW output. A separate air compression plant would be used. Economic evaluations indicate that, for gas prices above $1.95 per GJ, a 344 MW CAES plant is more economic for intermediate/reserve load duty than simple cycle gas turbines.

Jan 1, 1992

Construction work on one of the world's largest landslide stabilisation projects is drawing to a close in Central Otago. Begun in mid 1990, major stabilisation work has been carried out on seven large rockslides which will be partially inundated when the Clyde dam reservoir (Lake Dunstan) is filled. The work has required the construction of 14.5 kilometres of tunnel, 60 kilometres of surface drilling, 78 kilometres of drilled drainage holes and five million cubic metres of earthworks. The stabilisation programme has been carried out by the Electricity Corporation of New Zealand as part of the Clyde Power Project, a hydroelectric development on the Clutha River.

Jan 1, 1992

By F. Woller

The territory of Czechoslovakia is well endowed in deposits of a variety of industrial minerals. At present, 29 different types of industrial minerals are mined from some 600 individual deposits in Bohemia and Moravia only. About half of those production centres involves structural materials like aggregate and common brick clays and loams. A significant proportion of industrial minerals produced in Czechoslovakia are exported. Destinations of main products are shown in Figure 1. Production of industrial minerals in Czechoslovakia has a long history. Glass has been produced since the 14th century, sulphuric acid since 1578, graphite since 1750, and chinaware since 1790, to name just a few; but most of the present production comes from deposits developed during the past forty years. For a variety of reasons, only about 30 per cent of registered and explored industrial minerals deposits in the country are in production (Table 1). Two of the reasons may be the complexity of processing or conflicting interests of parties involved, but lack of market research, investment funds, or processing capacity have also had an impact on the level of utilization of the resource base.

Jan 1, 1992

By S. Auger, S. McDonald, K. Ward

"This preliminary paper provides a summary of lab and mill flotation investigations into the copper collector at two Canadian operations. The orebodies illustrated in these studies both contain mainly copper and zinc with uneconomic quantities of lead. Silver is also present as a secondary precious metal.Each mill has advanced to the extended mill trial stage with Uniflot SP129 as the sole copper collector. The preliminary metallurgical results have indicated higher copper circuit zinc and lead rejection is possible as shown in Case Study #2. In Case Study #1, improved zinc circuit metallurgy has been realized during all the Uniflot copper circuit collector trials. A slight increase in silver recovery has also been observed in the extended trials at both operations. INTRODUCTIONThe Canadian base metal industry is presently going through a rationalization period in response to low metal prices and low grade ore bodies. The response from flotation mills has been to reduce costs by incorporating new technologies such as energy efficient large cells, low moisture pressure filters and low steel consumption SAG mills. Other optimization strategies have been incorporated to get better metallurgical performance such as improved process control and monitoring techniques.The newer flotation plants have embraced many of the latest equipment innovations but they continue to incorporate off-the shelf reagents like xanthate and methylisobutylcarbinol (MIBC) . New collector chemistries have been mostly unsuccessful. Our approach incorporates the best of the old and new chemistry into proprietary formulations that match the application. We have found most single chemical formulations cannot meet the demands of the optimized modern flotation plant."

Jan 1, 1992

The coal-bearing strata of Oklahoma occur in the eastern part of the state over an area of 14,500 square miles, 20.7 percent of the state's total area. Commercially valuable deposits of bituminous coal cover about 8,000 square miles in seams ranging from ten inches to five feet thick. Estimated reserves in Oklahoma are 1.6 billion tons, representing 0.3 percent of U.S. coal reserves. The vast majority of coal mined in Oklahoma used in a single power plant within the state. Oklahoma gained primacy when its regulatory program was conditionally approved January 19, 1981. Authority for the state to administer the Abandoned Mine Land program was granted January21,1982. On April 30,1984, the Office of Surface Mining substituted direct federal enforcement of the inspection and enforcement portions of the Oklahoma program. This substituted enforcement was based upon a finding by OSM that Oklahoma had not operated the inspection and enforcement portions of its program effectively. As of January 1, 1986, Oklahoma inspection and enforcement authority was reinstated. Full program authority was granted to Oklahoma on January 14, 1986.

Jan 1, 1992

By Nathan A. Tiner

Sulfuric acid anodizing process is extensively used in many industrial and consumer products to provide corrosion resistance to aluminum alloys. The anodic coatings produced consist of amorphous alhnum oxide with a pornus structure which is easily sealed and colored with dyes. The coatings may contain defects due to surface flaws, canposition and microstructure of the aluminum alloy, and/or due to the anodizing process conditions. This paper will describe the techniques used in anodizing process, various defects which may be produced in anodic coatings and the methods to control them.

Jan 1, 1992

In 1987 Wyoming became the largest coal producing state in the country. The state is known for its extensive coal resources and extremely thick coal seams. Wyoming's coal reserves total about 69.3 billion tons, or 14.2 percent of the U.S. coal reserve. Coal seams range generally from 10 to 80 feet in thickness, although one seam is 220 feet thick. The coal-bearing areas of Wyoming underlie approximately 41 percent of the state's total land area. Wyoming's coal ranges from lignite to high volatile bituminous. Most of the coal produced is subbituminous from the Powder River coal region near Gillette. The presence of coal in Wyoming was discovered before 1834 on the Belle Fourche River. The state's first mine opened in Carbon County in 1865, and with the completion of the trans- continental railroad, the demand for coal increased. Currently approximately 80 percent of Wyoming's coal production is shipped out-of-state to meet the growing demand for low- sulfur coal to fuel electric generating plants. Wyoming received conditional regulatory approval November 26, 1980. Its Abandoned Mine Land Program was approved February 14, 1983.

Jan 1, 1992

By Peter A. Rona

The Mid-Atlantic Ridge in the central North Atlantic and the Gorda Ridge within the U.S. Exclusive Economic Zone off northern California and southern Oregon are yielding new discoveries of seafloor hydrothermal mineralization. The TAG hydrothermal field in the rift valley of the Mid-Atlantic Ridge near 26 degree N, 45 degree W has been a site of international collaborative research since the discovery there of extensive manganese deposits associated with low temperature hydrothermal activity in 1973 as part of the TAG (Trans-Atlantic Geotraverse Project). The first high-temperature hydrothermal activity, massive sulfide deposits and vent biota discovered in the Atlantic were found at the TAG hydrothermal field in 1985. Collaborative dive series with DSV ALVIN in 1990 and in 1991 with the two Russian MIR submersibles in the TAG field have found and sampled large inactive sulfide mounds in addition to the previously known active sulfide mound. The active sulfide mound on the floor of the rift valley is about 250 m in diameter and 40 m high with a concentric zonation of mineral types and flow regimes decreasing in temperature from 365 degree C black smokers at the center to white smokers and diffuse flow toward the margins. The recent dive series in coordination deep-towed instrument surveys have delineated a zone extending about 5 km along the lower east wall of the rift valley of inactive sulfide mounds up to a kilometer in diameter. MIR Mound in this zone consists of a central sulfide zone about 400 m in diameter and 50 m high surrounded by a halo of low-temperature deposits to 200 m wide. Inactive sulfide chimneys contain the first primary, free gold grains found at a hydrothermal site on a mid-ocean ridge (P.A. Rona, Y.A. Bogdanov, E.G. Gurvich, N.A. Rimski-Korsakov, A.M. Sagalevitch and M. D. Hannington, 199 1 EOS, Transactions, American Geophysical Union, 72:470-471 and Journal of Geophysical Research, submitted).

Jan 1, 1992

By P. A. Lindberg

Early Proterozoic ore deposits in the Verde district at Jerome, Arizona have produced 33.7 million metric tons of ore (1893-1975). The United Verde and United Verde Extension deposits produced most of the ore that yielded 1,644,323,100 kg Cu plus large amounts of Au, Ag, and Zn. These deposits are situated on the fractured and hydrothermally altered apex of a large submarine rhyolitic extrusive (Cleopatra formation). Precambrian lithologies are penetratively deformed and at Jerome the Fl folds plunge steep to the NNW. For the past two decades the volcanogenic model has superseded the replacement theory of ore formation.

Jan 1, 1992

By S. Behl

A major limitation in developing successful selective flocculation schemes is the difficulty encountered in adsorbing the polymeric flocculant only on the desired substrate. In this paper a correlation between selectivity of flocculant adsorption and separation efficiency is outlined and a potential technique to achieve selective adsorption of flocculants is discussed.

Jan 1, 1992

By McNicol M. D

Petroleum exploration in onshore Gippsland was directed in the 1950s and 1960s towards plays in the basal Latrobe and Strzelecki Groups, but these became forgotten in the 1970s with the Latrobe play discoveries offshore. The principal explorationists of the time were Woodside Oil and Arco Ltd, who then departed the scene after drilling some 18 wells without major success. In the late-1980s successful hydrocarbon finds in equivalent age Otway Group sediments in the Otway Basin were made and in early 1990 Tyers Petroleum began investigations into Strzelecki Group prospects as applied to the onshore Gippsland Basin. Some 18 anticlines have been mapped, based on shallower coal exploration drilling in the Latrobe Group, which from seismic and gravity evidence are believed to unconformably overlie similar anticlinal structures in the underlying Strzelecki Group. Strzelecki targets of interest within drilling depth are the basal Tyers Conglomerate/Rintouls Creek Sandstone Formations which outcrop in the north of the Latrobe Valley and are analogous to the Pretty Hill Sandstone in the Otway Basin. In addition, intra-Strzelecki Group targets similar to Heathfield and Windermere Sandstone Members are also considered to be present. Good source rocks are abundant including coal seams and carbonaceous sediments of Neocomian and Jurassic age, which lie within the oil window. Seal is provided by the overlying Aptian-Albian aged volcanogenic sediments. The Tyers/Rintouls sandstones - a target in the Woodside/Arco wells, with two exceptions, were not reached. Encouraging intra-Strzelecki shows were reported in many of the wells. Basal and intra-Strzelecki porous quartzose sandstones remain one of the few untested plays left in the Gippsland Basin and, in the onshore, merit extra attention as they he within the oil window at economically drillable depths.

Jan 1, 1992

By McGuckin P. H

The Cadjebut orebody is a MississippiValleyType (MVT) zinc-lead deposit, and is located approximately 80 km southeast of Fitzroy Crossing in the Kimberley region of Western Australia. It is one of five zinc rich orebodies discovered by BHP Minerals in the region.The participation in the Cadjebut Joint Venture is BHP Minerals limited (Manager), 58 per cent and Billiton Australia Limited, 42 per cent.The mineralisation is contained in gently dipping dolomitised limestone sediments (part of the Lennard Shelf carbonate sequence) with an orebody width of between 60 and 120 m and a strike length of approximately 3 km. The deposit consists of two thin, stratabound shallow dipping orebodies, one overlying the other, to provide discrete but not independent mining areas. The orebody contains approximately 2.1 million tonnes of recoverable ore at an approximate grade of 12 per cent zinc and four per cent Lead.

Jan 1, 1992

By Renwick MT

Two innovative ground reinforcement products have been developed for use in the mining industry. One of these products is a high strength polyethylene (HOPE) bar for use as a rib bolt in underground coal mining and as a corrosion proof tendon in open pit mines. The other product is a cable bolt (Ultrastrand) which demonstrates enhanced load transfer and is available in continuous lengths. Ultrastrand's exceptional in- situ performance and versatility makes it ideal for mechanised installation in both underground and surface mining operations. Details of these products are presented and results from labortaory and field trials are discussed.

Jan 1, 1992

By E. Martinez

A heavy mineral sand sample was tested containing 13% heavy mineral consisting of rutile, zircon, and ilmenite. Eleven tests were run at a mill site with a Mineral Deposit Limited MG 4 spiral to determine the effect of the addition 0; magnets to the spiral compared to conventional gravity separation. Different magnet configurations and field strengths were tested. Optimum results were obtained with the spiral retrofitted with magnets. The heavy mineral content of the concentrate was increased from 55.5% in the control to 64.2% with the magnets. The 8.7% improvement in heavy mineral recovery was due not only to the weakly-magnetic ilmenite, but also to increased recoveries if the non-magnetic zircon and rutile. The increased recoveries were achieved with no loss of concentrate grade.

Jan 1, 1992

By H. Soto, J. Jara, F. Nava

"A combination of oxidation and precipitation was used to eliminate cyanide from gold milling effluents. Preliminary laboratory work developed with both synthetic cyanide solutions and with industrial effluents indicated that ozone can easily destroy free cyanide and weakly complexed cyanide (i.e. copper and zinc cyanide). In this case the reaction is quite fast and seems to be controlled by the mass transfer of ozone to the solution. Experimental results indicate that free cyanide and weak-acid dissociable cyanide in mill effluents can be reduced to less than 1 ppm. However, the iron-cyanide complexes proved to be quite resilient to destruction with ozone and they remained in the solution even after most of the free and weakly complexed cyanide was destroyed with ozone. These results were confirmed in a pilot trial developed at the Sphinx plant in northern Quebec.To deal with the problem presented by the presence of the iron complexes two different approaches were studied: use of a combination ozone-ultraviolet light oxidation, and the precipitation of iron-ferrocyanide complexes in the residual solution after ozonation. This last method proved quite promising since reduced the total cyanide levels of industrial solutions assaying as much as 250 ppm to less than 1 ppm of total cyanide. Control of the · pH of the solution was the key to obtain the precipitation of the iron complexes. The use of iron to precipitate cyanide complexes has the advantage of being less expensive and less toxic than copper (used by the Inco process)."

Jan 1, 1992

By M. D. Monroe

Getting the best match between truck and haul road requires examination of many factors and their effect on the bottom line. Most mines use a bottom line measure based in some way on cost per ton of material moved. This measure focuses on the two components of truck haulage cost per ton: productivity (or performance) and operating cost. Productivity can be measured or predicted for specific tasks using either field measurement or modelling. Individual tasks can be combined to provide a larger scale, longer term net figure for total mine output. True cost is more difficult to capture as they are time and task oriented and can be influenced by a summation of factors over a truck lifetime. For example, "allocated" costs, such as owning (depreciation) and some repair costs, are spread over long periods of time. Other cost, such as fuel and tires can be tied more directly to certain tasks such as fuel and tire cost. This paper focuses on the more direct, task-oriented factors that affect truck productivity and cost.

Jan 1, 1992

By Manca PP, Rossi G, Lipari D, Knissel W, Massacci G, Licheri P, Fioravanti E, Helms W, Lai S

Mining of the massive complex sulphides orebodies of Campo Pisano and San Benedetto (Southern Sardinia, Italy), dates back to before Christ, though their exploitation with modern technology was only resumed in the middle of the last century. The increasingly adverse economic conditions and the weakness of both country rock and mineralization were concurrent in forcing the Company's management to develop suitable high-productivity stoping methods. In the framework of a project fi- nanced in part by the Commission of the European Coranunities, and carried out in cooperation with the Universities of Cagliari (Italy) and Clausthal (Germany), a cemented backfill stoping method was developed. The concrete mix preparation and placement facil- ities, study of the cement mixes and endeavaa-s to optimize the methods are described. The monitoring system for measuring stress evolution within the emplaced backfill is illustrated together with the successful replacement of part of the Portland cement

Jan 1, 1992

By M. A. Boucher

The purpose of my presentation is threefold: a) to make you aware of what is available in Canada in terms of refractory minerals. b) indicate the mineral deposits that have potential for development. c) show the advantages of Canada as a supplier of electrical energy necessary for the production of electrofused minerals. Canada is a producer of natural refractory minerals, electrofused minerals, and synthetic refractory minerals. Several deposits also have good potential for development. The natural refractory minerals produced in Canada are shown in Table 1. The major minerals by decreasing order of importance in terms of tonnage and values are: dolomite, graphite and magnesite.

Jan 1, 1992

By Batric Pesic

Recovery of gold from refractory ores was studied by pressure oxidation as the method of ore pretreatment followed by bromination of oxidized residues. Three different ores were examined, Au-Ag, Au-Ag-Te, and Au-silver free ore. Pyrite was the major host mineral for gold in these ores. The effect of pressure oxidation parameters (temperature, pressure of oxygen, time, and pulp density) on subsequent bromination under standard conditions was examined. Bromination of residues produced under standard pressure oxidation conditions was examined as a function of: temperature, bromine and sodium bromide concentration, and time. Recovery of gold on activated carbon, from the pulp after bromination, was studied too. Recovery of gold from silver containing ores was lower (87-91%) than the recovery of gold from silver free gold ore (97%). In each studied case, the presence of activated carbon in the pulp further increased the recovery of gold.

Jan 1, 1992