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By N. P. Reddy, Y. J. Wang

This paper describes an experimental setup for multiple fan ventilation systems at the ventilation laboratory of the West Virginia University Department of Mining Engineering. Housed in a 30-ft x 70 -ft room, the experimental setup consists of three 18-in., variable-speed, axial flow fans; an 18-in. -diam, fiberglass tubing; associated fittings for arranging networks; and a picot-tube measuring and data-acquisition system. The fiberglass tubing and fans can be organized into non-planar networks of two or three fans. The setup is mainly designed for studying the characteristic curves, operating points and fan stall for multiple fan ventilation systems.

Jan 1, 1993

The passage of a vast array of new State and Federal environmental legislation over the last couple of years has required many mine operators to sharpen their focus on environmental requirements. Established requirements, such as environmental impact assessment, minimising disturbance and rehabilitation must now be complemented by mine environmental management plans. These may not only require regular monitoring of mine operations and detailed forward planning to prevent or reduce environmental harm caused during mine operation, but annual updating. It is likely that in future these plans will be required to incorporate general principles such as pollution prevention, sustainable development, waste minimisation and conservation of biodiversity and ecological integrity.

Jan 1, 1993

By Roy M. Schnabel

The Fashion Island Boulevard Bridge over the Marina Lagoon in San Mateo, California is an eight span precast, prestressed concrete girder bridge. It is approximately 495 feet in length and 61 feet in width. It is supported on 36" diameter octagonal, hollow precast-prestressed concrete pile columns. The bridge was constructed in 1968 and suffered considerable damage during the Loma Prieta Earthquake in 1989. A damage survey report prepared by the State's Office of Emergency Services (OES) recorded that sixteen of the twenty-one pile-columns sustained heavy to moderate damage from the Loma Prieta Earthquake. The damage consisted of cracking and spalling at the tops of the pile-columns. Spalls at the most heavily damaged columns exposed the prestressing strands and confinement reinforcing which also showed signs of corrosion.

Jan 1, 1993

By Richard L. Rains

In 1992, the Bureau of Mines evaluated mineral resources of the 34,043-hectare Caribou City and 41,943-hectare Stump Creek study areas in southeastern Idaho. No resources were delineated. The areas had been proposed for wilderness. Rocks underlying the study area are part of the Idaho-Wyoming Thrust Belt. At Caribou Mountain they have been intruded by diorite-monzodiorite. Where the intrusive rocks contact calcareous members of the thrust belt, skarn bodies have formed that host metal deposits. Gold, both placer and lode, occurs in the Caribou City area, and salt occurs in the Stump Creek area. Production records show 73.5 kg (2,363 ounces) of placer gold were produced; however, field studies indicate more than 2,000 kg (67,000 ounces) probably were recovered. Minor amounts of lode gold, silver, and copper were recovered from the hard rock mines. Production of salt from the Stump Creek study area in the 1860's was used by emigrants on the Oregon trail and also shipped to various mining districts for use in silver recovery. Oil and gas were drilled for, but all holes are plugged and abandoned. There are no current leases. Examined workings consisted of 25 adits, 3 shafts, 50 prospect pits, and extensive placer workings all in the northern tip of the Caribou City area, Current BLM records show 168 placer and 146 lode claims; 14 claims are patented.

Jan 1, 1993

By Alan R. Buehler

The Bureau of Mines conducted a mineral investigation of the 32,270-hectare Cache Peak study area in 1992; the area had been proposed as wilderness. Bureau personnel examined and sampled prospect workings; 50 rock and placer samples were taken during the investigation. The study area is centered about 25 km southeast of Challis, Idaho, in the Challis National Forest. According to May, 1993, Bureau of Land Management mining claim records there were no current mining claims located inside the study area. Up to 100 claims may have been located in the study area in the past. Gold, silver, copper, lead, zinc: Significant analyses, poor exposure precludes resource estimate. Limestone: More than I billion tonnes may be chemically suitable for a variety of uses, markets too distant to favor mining. Dolomite: More than 1 billion tonnes may be chemically suitable for producing magnesium metal, markets too distant to favor mining. Sand and Gravel: Several million m3, but markets and transportation costs do not favor mining. Chalcedonic nodules: Two localities in the study area may be of interest to hobbyists who cut and polish stone. There is no reported past production from the study area.

Jan 1, 1993

By Shulin Nie

The dead-pressing phenomenon in emulsion explosives is wellknown. Research work on this subject has been carried out at the Swedish Detonic Research Foundation for the last few years. Several experiments with emulsion explosives under dynamic pressure condition have been carried out both in iron pipes and in blast holes in rock. The main object was to study the critical amplitude and duration of the pressure causing the explosive to be dead-pressed.

Jan 1, 1993

In this paper the reactions which may lead to particle hydrophobicity/hydrophilicity as a function of grinding environment-are reviewed. The results of pulp chemical investigations related to a Cu-Pb-Zn ore on a pilot plant scale and laboratory tests with a Pb-Zn ore to evaluate the effect of some inhibitors on grinding/flotation are presented. The flotation recoveries of the ores treated by conventional and autogenous grinding methods show only a marginal difference and the results favour autogenous grinding. Iron originating from several sources manifests in the form of insoluble hydroxy complexes in the pulps. Such metal hydroxy complexes are hydrophilic and coat the mineral surfaces indiscriminately. On the other hand, selectivity is a problem for pulps ground by autogenous milling. Some corrosion inhibitors used in the laboratory grinding/flotation tests on a Pb-Zn ore showed maximum reduction in the wear of the grinding media ranging from 25 - 36 per cent, depending on the type and concentration of the inhibitor.

Jan 1, 1993

By Hall ST, Miles NJ

Recently an inorganic salt, sodium polytungstate (SPT), has become available that allows the preparation of non-toxic solutions of relative densities up to 3.1. It is relatively expensive and at the higher relative densities achievable, highly viscous. Alternative inorganic compounds may in the future be identified that overcome these limitations. The Australian Mineral Industries Research Association Ltd (AMIRA) has initiated a project to examine possible alternatives. However, it has been found that by the addition of finely divided ferrosilicon to solutions of SPT, relative densities of up to 4.0 can be achieved. A laboratory technique for density fractionation of sized mineral samples utilising this finding has been developed. This is currently being extended to study the potential applications of such liquids and suspensions in dynamic systems for mineral, coal and recycled waste separations.

Jan 1, 1993

By Ian J. Duckworth, Pierre F. X. Mousset-Jones

A detailed heat flow project was conducted at the Homestake Mine in Lead, South Dakota. This paper presents results obtained from a stope sensor system installed in the mine. The design and installation of the system are described in detail in a previous paper (Duckworth et al., 1992). The major project objective was the construction of a comprehensive heat flow data base to allow the design and testing of a new climate prediction model applicable to irregularly shaped underground excavations in non-homogeneous surrounding rock types. A mechanized cut-and-fill (MCF) stope contributes a substantial overall heat source in a mine, and the effect of this source on the working environment must be considered when planning future ventilation and refrigeration requirements. The relative magnitudes of the component heat sources encountered with the MCF mining technique are presented, having been computed from actual stope beat flow data collected over a one-month study period. The percentage of the overall heat load that is removed from the scope for each component heat sink is evaluated, and the overall energy balance is analyzed. A one-month study length was considered a sufficient period of time to allow stope monitoring for a complete range of mining conditions.

Jan 1, 1993

Grade control is an important factor in the on-going success of a mining operation. Grade control criteria will vary depending on the commodity being mined. Financial considerations determine the actual grade control criteria at any one mine site. Mining and metallurgical capital and operating costs are ultimately used in ascertaining cut-off grades employed in grade control. The metallurgical characteristics of the ore, and ultimately the equipment selection and design of the plant, are based on samples provided by the exploration geologist. Ore variability is an important factor in designing the process plant. Ore variations, outside of those catered for in the design, as well as large ore changes on a daily basis, will impact on the metallurgical performance, and hence the economics of a mining operation. Therefore good liaison between the grade control geologist and metallurgist will undoubtedly lead to a more consistent, and more profitable mining operation.

Jan 1, 1993

By H. L. Monro

CONTRIBUTION BY J. R. F. HANDLEY Mr Monro is to be congratulated on his concise treatment of a very complex subject. As a graduate with only Mathematics I in my curriculum, I am unable to comment on the mathematical treatment of the factors affecting his supply/demand model, but the logic does not escape me. The main conclusion is that any excess of supply to the spot gold market will depress the price in a normal market, and particularly in a falling market.

Jan 1, 1993

By J. R. Cobble

Dissolution of chalcopyrite with acidified ferric sulfate produces a sulfur layer on the unreacted chalcopyrite surface that interferes with further dissolution. The U.S. Bureau of Mines has developed a process to improve the leaching kinetics of these types of diffusion-controlled systems. The system features the Bureau-developed turbomill, an attrition grinder that scrubs the reaction product coating away from the unreacted mineral grains during leaching. The system can be operated continuously at any temperature up to the boiling point of the leaching agent. This method is a hydrometallurgical alternative to chalcopyrite smelter technology and eliminates sulfur dioxide emission problems with its associated costs. Batch testing at 900 C with the chalcopyrite-ferric sulfate system resulted in copper extraction exceeding 99 pct. At an optimal energy consumption of 1,520 kW· hjst, 95 pct of the copper was extracted. The pregnant liquor was clarified and tested for typical solvent-extraction recovery of the copper. Two-stage extraction and two-stage stripping recovered 96 pct of the copper in an electrolyte suitable for copper electrowinning.

Jan 1, 1993

By Earl Gebhardt

"The planning and design of mining panels in the Potash Corporation of Saskatchewan Inc., Lanigan Division mine Block B involved a number of investigative techniques. The techniques utilized to gain insight into the viability of mining included2-D and 3-D seismic surveys, longhole drilling, exploration wells, photo lineament, magnetic and gravity surveys, and actual room excavation.IntroductionPotash Corporation of Saskatchewan Inc. (PCS) owns and operates four potash mines in the province of Saskatchewan. The Lanigan Division mine is located 110 Ian east of Saskatoon, Saskatchewan, near the town of Lanigan.The Lanigan Mine commenced production in August 1968under the ownership or Alwinsal Potash of Canada Limited. The mine was purchased by PCS in 1977.Lanigan Division's productive capacity is 3.4 million tonnes of product per year. Ore is extracted from the "" B"" zone or Layer III or the Patience Lake member of the Prairie Evaporite, more than 1000m below surface . The Patience Lake member (approximately 20 m thick) consists of potash interbedded with salt. The average run-of-mine ore grade is 21070 K20 (Fig. I).The mine was initially developed using the room-and-pillar technique. Improvements in mining resulted in the use or extensible conveyors in long panel rooms."

Jan 1, 1993

By B. Morris

This presentation will describe the process by which the Quebrada Blanca (QB) copper project in northern Chile was financed. It will also show how a relatively junior mining company addressed the problems created by its inability to provide its share of the equity funding and the guarantees required by the project lenders. QB is located in the semi-arid Andean highlands of northern Chile, 170 kilometres southeast of the port of Iquique and 30 kilometres west of the border with Bolivia, at an altitude of about 4,300 metres (14,000 feet). Figure 1 depicts the project's location. The QB orebody is a secondarily enriched porphyry copper deposit containing reserves of 85 million metric tons grading 1.3 percent copper. Underlying the enriched zone is a significant primary ore zone containing several hundred million metric tons grading about 0.5 percent copper. In the late seventies and early eighties Falconbridge and its affiliates spent $20-30 million dollars exploring the deposit and conducting feasibility studies. For a variety of reasons they decided not to develop the property which was returned to its owners, Empresa Nacional de Mineria (ENAMI), which is a Chilean state mining corporation. In 1988 ENAMI announced its intention to privatize the property through a public bidding procedure.

Jan 1, 1993

By Zhang Hengzhong

Ni-P-Fe slag is the by-product in the production of phosphate fertilizer in blast furnace with nickel contained serpentine ore as the raw material. It contains nearly 5-7% Ni, 65-7( Fe, and 10-12% P. The slag is very hard to process, it neither dissolves in aqueous ammonia, nor in sulphate acid. In the stiff the technique to treat the slag in order to extract valuable nickel was developed, it essentially consisted of the processes of roasting, leaching, separation and purification. Nickel sulphate was prepared with this method.

Jan 1, 1993

By Michael D. Odekirk

The U.S. Bureau of Mines investigated solvent extraction methods for recovering scandium from water leach filtrates of sulfated tantalum tailings. These complex solutions typically contained 20 or more metals in significant quantities. Two commercially available organics, DEHPA and PC-88A, were identified as effective scandium extractants. The two organics were tested in continuous solvent extraction circuits to compare loading and stripping kinetics, recyclability, and general processibility. Results showed that 95 pct of the scandium, greater than 80 pct of the zirconium, and only small amounts of other solubilized metals were extracted. Scandium was stripped directly as a 3.6 pct Sc precipitate when a 3n NaOH liquor was used as the stripping agent. This precipitate was subsequently upgraded to 94 pct ScE3 via a selective HE leach.

Jan 1, 1993

The status of remote sensing data availability in New Zealand is outlined and discussed. Currently, two multispectral remote sensing satellites are providing regular data over New Zealand; aircraft scanner services are available from Australia.; operational radar satellite services are yet to materialise. The advantages and disadvantages of the various data types are compared and contrasted. Some image processing considerations are outlined.

Jan 1, 1993

By Natsumi Kamiya

The Metal Mining Agency of Japan (MMAJ) has started the project in the fiscal year of 1989 under the administration of the Ministry of International Trade and Industry '(MITI). The purpose of this study is to assess the impact on the ocean environment caused by manganese nodules mining. Summary of research and survey of MMAJ is as follows: 1. Evaluation of environment impact The aim of this study is to assess impact for ocean environment by manganese nodules mining. It is studied by using three-dimensional hydrodynamic prediction model and by carrying out cultural experiment of surface fauna with adding deepsea water and sediment. Development of hydrodynamic prediction model for discharged water at ocean surface has started in 1989. On board cultural experiment was carried out in the Japanese application area in the eastern Pacific in May 1991 and in May 1992.

Jan 1, 1993

By Kenneth N. Han, Xinghui Meng, A. J. Monhemius, G. W. Warren, E. Peters

The leaching of gold in ammoniacal solutions containing various oxidants in an autoclave has been investigated. Also studied are thermodynamic and kinetic aspects of the ammonia leaching of gold and silver. The variables studied included stirring speed, temperature, concentration of ammonia, ammonium, and various anions. Arrhenius activation energy values were found to be between 47.1 kJ/mol and 86.2 kJ/mol depending upon the kinds of oxidants used. An electrochemical reaction controlling mechanism has been proposed for the dissolution reaction. The leaching behavior of gold and silver from various ores in ammoniacal solutions containing various oxidants has also been investigated. The samples tested included sulfidic as well as carbonaceous refractory ores. The recoveries of gold and silver from these refractory ores were better than 96% within 2-3 hours of leaching time.

Jan 1, 1993

By Steve Kral

Amax Coal Industries Inc.'s Delta Mine is a medium-sized. high-sulfur coal producer that has lived up to the challenges posed by nearly six decades of a highly competitive domestic coal market. The mine now faces one of its biggest challenges - the same one staring at the dozens of other high-sulfur producers in the Midwest - the Clean Air Act Amendments of 1990. The 59-year-old mine, located in the coal fields of southern Illinois, has remained one of the state's oldest continuously operating mines by rolling with the ups and downs of the coal market and by incorporating new technologies and innovative productivity improvements into its operation.

Jan 1, 1993