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By Edward L. McHugh

Mineral resources in the Silver Creek study area of the Nez Perce National Forest. Idaho, were investigated during the summer Of 1989. The study area includes the 36,100-acre Silver Creek-Pilot Knob RARE II area (No. 1-849) on the north side of the South Fork Clearwater River, about 11 miles west of Elk City, 10. Mines in and near the study area in the Tenmile and Newsome mining districts produced about 100.000 02 of gold, mostly from placers. Gold production had an historic value estimated at 52 million, equivalent to nearly $40 million at today's prices. Lode mines produced about 19,000 oz of gold, along with smaller amounts of silver, copper, lead, and zinc. Of 34 mines and prospects examined, ten lode properties are considered to be significant by virtue of their past development or production and the presence of possibly ore-grade mineralization. There are no identified mineral resources in the study area; however, samples that contained gold and anomalous arsenic delineate a three-mile-long area from the Sentinel mine, north to the Blue Quartz prospect where exploration might disclose resources. One mining company is conducting geophysical studies and drilling within the delineated area. In addition, six placer sites may contain enough gold to be of possible interest for future exploration and development.

Jan 1, 1991

By William A. Apel

Several different strains of bacteria have been shown capable of reducing hexavalent chromium, Cr(VI), to Cr(III), a less toxic, .. more readily recoverable form of Cr. This paper examined the Cr(VI) reduction efficacies of 3 different Cr(VI) reducing bacteria: Pseudomonas f1uorescens LB300., Pseudomonas aeruginosa PAOI, and Pseudomonas aeruginosa PAOI (pCROI) It was demonstrated that all three bacterial stratns reduced Cr(VI) primarily during their exponential growth phases while using glucose as their carbon and energy source. Significant differences in the three organisms' Cr(Vl) reduction capabilities depending on initial Cr(VI) concentrations were also demonstrated. P. aeruginosa PAOI showed superior Cr(VI) reducing capabilities over the. entire range of Cr(VI) concentrations tested while the Cr(VI) reduction capabilities of the other two strains were increasingly inhibited as Cr(VI) concentrations increased.

Jan 1, 1991

By M. K. Gangal, E. D. Dainty, G. Kunchur

This paper presents a validation of C02 as a single surrogate measurement for other diesel-emitted pollutants in multi-diesel-machine operations typical of small underground mines. This means that the simple measurement of C02 alone can be used to estimate the concentrations of other components of diesel exhaust in the mine environment. The linear relationship of C02 concentration with other diesel-emitted pollutants was indicated by the results of simultaneous real-time monitoring of C02 with CO, NO, NO2, SO2, Respirable Combustible Dust (RCD), and Air Quality Index (AQI) in several small underground mines. The SO2 was not directly measured but calculated from the measured C02 concentration and diesel fuel analysis for carbon, hydrogen and sulphur. The measurements were made in the return air drift under various mining conditions involving a number of diesel LHDs and haulage trucks. The statistical analysis and mathematical representation of the several components of diesel pollutants with C02 are presented. Regression analysis shows that at the 1 percent level of significance there is a strong linear relationship of these diesel pollutants with C02. This relationship is discussed in detail, concluding that C02 measurement alone is a good indicator of overall mine air quality and can be used as a control parameter.

Jan 1, 1991

By Jon Y. Kaneshiro, Donald W. Scapuzzi

The primary purpose of the Prototype Installation Facility (PIF) for the Superconducting Super Collider (SSC) in this conceptual design was to test the magnets and other physics equipment. PIF was located in the northwest quadrant of the SSC 54 mile (87 km) main ring and consists of the first segment of tunnels, approximately 17,060 lineal feet (5.2 km) of 12 foot inner-diameter (ID) (3.7 m) tunnel, three 250 ± foot (60 m) deep shafts, connecting tunnels, and associated niches and alcoves. PIF would be the first portion of the main ring collider tunnel to be constructed. The geology, underground excavation conditions, underground facilities, and contractual considerations are discussed.

Jan 1, 1991

By McLeod RL

The Tolukuma gold-silver prospect is located approximately 100km N of Port Moresby in the Central Province of Papua New Guinea (PNG). Epithermal "adularia-sericite" style mineralisation crops out over 1200m within an en echelon quartz veined zone 1 to lOm wide. At a 4g/t cut-off grade, a geological resource of approximately 1.47Mt @ 13.77g/t Au is indicated from 38 diamond drill holes completed since discovery by Newmont Pty Ltd in September 1986. At a regional scale, Tolukuma miner- alisation appears localised in a dilatant zone at the intersection of a 1150 magnetic structure, and the western margin of a N-S trending graben which is filled by a Pliocene volcanic complex contemporaneous with the Mt Davidson Volcanics 30km to the W. A l0km diameter circular Landsat feature, which may reflect magma emplacement at depth, occurs immediately N of Tolukuma and nearby mineralisation. Mineralisation at Tolukuma occurs in sub-vertical quartz veins at, or adjacent to the faulted contact between Pliocene basic and intermediate volcanics/intrusives, and quartz mica schists and phyllites of the Cretaceous Kagi Metamorphics. Most veins display evidence of multiple episodes of brecciation and textures indicative of cyclic boiling, including crustiform rhythmic banding and quartz pseudomorphs after platy calcite.

Jan 1, 1991

By J. M. Goris

"Researchers at the U.S. Bureau of Mines are conducting research on cable-type ground supports to assess their material and support properties and to provide design criteria for implementing cable supports as a workable roof control system under various underground mining conditions. Much of this work involves laboratory assessment of the material and support properties of cable supports using both conventional and birdcage steel cables. Included in this assessment are single and double cables, effects of changes in embedment length on support strengths, water-cement ratios, use of breather tubes, and pumpability and water-bleeding properties of grouts.IntroductionSince cable supports were introduced in the early 1970s, considerable research has been conducted in laboratories and at mine sites to understand their behaviour. The U.S. Bureau of Mines began a laboratory evaluation project in 1985 at the Spokane Research Center (SRC) to study the behaviour of cables supports under uniaxial loads so that the effects of various cable support components, such as grout and breather tubes, could be identified. Other objectives were to compare the behaviour of various types of cables and grouts and to collect meaningful data for numerical analyses. Pull tests were conducted to determine how cables supports reacted under uniaxial loads and how they failed when ultimate loads were exceeded. Such data are essential for the development of numerical models for analyzing rock mass behaviour when the rock is supported with cables.Test ProgramBecause each cable support can be composed of either single or double cables as well as a breather tube, pull tests were designed to include a variety of samples containing these components. A series of samples containing a single conventional cable, a neat cement grout having a water-cement ratio of 0.45, and no chemical additives was selected as a standard (Table I). Then one component in the system, such as the presence of a breather tube, was changed, and results of tests compared to results obtained for the standard samples to determine what influence that component might have on the behaviour of the support system. If significant changes in test data occurred, they could be attributed to that one component. To control the quality of the samples, the physical condition of the cables and tubes were monitored closely, and compressive and tensile strengths as well as flow properties were determined for the grout used in each test series."

Jan 1, 1991

By Ulrich Neumann

Mining coal by employing a method called longwall mining is gaining more and more popularity in the United states since it offers many advantages over the conventional deep mining methods. Those advantages are a higher productivity, an almost total extraction of the mineral since no pillars must be left behind for support, and an increase in safety since the personnel are protected by the shield supports and rarely have to work near unsupported, exposed root. However, on some longwalls, the dust levels liberated by various equipment such as belt conveyors, chain conveyors, crushers, longwall shearers, and moving shield supports can exceed the maximum permissible limits and therefore have an adverse effect on productivity. Many attempts have been made over the past years to reduce the dust liberation by changing designs, installing various types of sprays or scrubbers, treating the mine water with wetting agents, or even using foam to catch dust before it becomes airborne. In the year 1984, the Bureau of Mines awarded Eickhoff Corporation a contract to demonstrate a water-jet-assisted cutting system for the multiple purposes of reducing dust levels, improving bit consumption, and increasing material size. During the previous phases of this contract, various trials were conducted aimed to design, build, and test d shearer loader to meet the objective of the contract. In the early stages of the research program, it was expected to see a reduction in the overall power consumption of the machine due to the fact that the high-pressure water jet would pre-cut the mineral in front of the bit. This, in turn, would then reduce the bit wear. Since there is less cutting action performed by the bit, a reduction of the dust liberation and a reduction of product fines was sought.

Jan 1, 1991

By R. P. Aldis

A wide range of mineral-derived products are required by the electronics industry for it to function. In one form or another, almost all the known elements have been experimented with and tested for various electrical applications. The two major areas for which minerals are used in electronics are as conductors and semiconductors. Conductors provide the means to transport and distribute electricity, while the main application of semiconductors has been to manipulate electricity. Silicon is the most widely recognized semiconductor material, but gallium, indium, and germanium are rated as the most important metals to the semiconductor industry for future and near future technologies.

Jan 1, 1991

By Robert B. Parsons

"Exploration and development of mineral resources in developing countries by Canadian-based multinational mining companies is becoming increasingly common. One problem being encountered is that the objectives of the governments of developing countries can differ from those of developed countries. These objectives are not always consistent with maximizing returns from the projects, which can create conflicts between the mining company's responsibility to its shareholders and the desire to be a good corporate citizen. This article discusses how a mining tax regime can be designed to make the social goals of a government consistent with the economic goals of the company.IntroductionAt the recent International Seminar on Mining Taxation organized by CIM and the United Nations there was considerable discussion about the role of international mining companies operating in developing countries. Not surprisingly, given the diversity of backgrounds of individuals attending the Seminar, there were different opinions about what this role should be.Government PositionRepresentatives of governments pointed out the strong desires of their countries for technology, high-level technical training of their workforce, increased employment, and development of social infrastructure. They pointed out that, to a large extent, these objectives could be more efficiently met by mining companies operating in the country than by the governments themselves. For example, a multinational mining company (""MMC"") would have extensive knowledge of the various technologies available, and would have performed a detailed evaluation of the mineral resources before choosing the most cost-efficient technology for that project. They would, therefore be in an ideal position to assist the country in importing and developing such technology. Similarly, the company could provide opportunities for hands-on training, both at the technical and managerial levels, which would otherwise be unavailable to the government."

Jan 1, 1991

By John R. Woodcock

The Kitsault molybdenum deposit lies along the east margin of thecoast Batholith Complex near the head of the fiord of Alice Arm. It is 800 km (497 miles) northwest of Vancouver, British Columbia. The deposit is located on Lime Creek 8 km (5 miles) from the coast on a wide dissected upland valley at an elevation of 600 m (1969 ft). It is an area of coastal rain forest with high annual precipitation and extremely high winter snowfall. Although the area is of high relief, outcrops are largely restricted to ridges and canyons. Most of the area is covered by the coastal vegetation or wet swampy upland areas. The south edge of the molybdenum deposit was exposed in a sharp canyon; however, outcrops over the remainder of the deposit were largely restricted to a few small exposures of resistant hornfels. The mineralization is related to an elliptical porphyry stock of 52.3 m.y. age which intrudes argillites and microgreywackes of the Late Jurassic Bowser Group. A circular zone of alteration, with a diameter of about 700 m (2297 ft), occurs in the north end of the stock and the molybdenite mineralization is concentrated in the outer parts of this zone of alteration. Thus, the northern part of the mineralization occurs partly in the hornfels and partly in the stock, whereas the southern side of the ring of mineralization cuts across the middle of the stock. Zoning within this system includes a central circular area of almost complete replacement of quartz plus K- feldspar and this grades sharply outward into a phyllic zone. Clay alteration is largely localized along late faults. The ring of molybdenite mineralization is partly overlapped and partly surrounded by a zone of pyrite mineralization. Some chalcopyrite is coextensive with the pyrite zone. Late polymetallic veins fill two conjugate fracture sets. These quartz veins contain galena, pyrite, some chalcopyrite, and a number of lead-bismuth sulfosalts.

Jan 1, 1991

By Ogilvie M

South Bulli is the oldest and largest underground coal mine in Australia. Two longwall units are in operation and current production is 2.5 to 3 million tonnes of run of mine product per year with a workforce of 600. Prior to 1984 a workforce of around 1,200 produced 1.5 million tonnes. Advances in technology can. of course, account for some of this gain, but the changes made in the human resources area are also seen as playing a major role in South Bulli emerging as a reasonably stable operation.The human resources strategy adopted recognises the value of the workforce and is aimed at not only fostering cooperation as all levels, but also making employees aware of the direct contribution they can make to the success of the enterprise.

Jan 1, 1991

By Budden J. R, Rhodes M. K

Bacterial oxidation technology was successfully applied in a mine site pilot plant for the treatment of refractory gold concentrates. The bacterial culture was proven capable of selectively breaking down the refractory sulphide minerals to release the gold. Gold extractions greater than 90 per cent were possible when oxidised concentrate was leached with cyanide solution. The pilot plant was designed using data scaled up from laboratory testing and sized for transport by standard vehicles. The bacterial culture used to break down the refractory gold-bearing mineral was a natural mixed culture able to withstand temperatures up to 55¦C, thus making the technology particularly suitable for use in Australian and in some North American gold mining regions. The pilot plant was operated at the mine site over a six month period. Performance of the bacterial oxidation technology under site conditions was as predicted from the laboratory testing. It was demonstrated that the culture was robust under normal site condi- tions and that the culture could withstand wide variations in the feed and the operating conditions, while still achieving satisfactory oxidation levels. The technology was able to be utilised by site operators and supervisors with minimum intervention. Design data for a commercial facility was collected for a number of different concentrate samples and a feasibility study completed. Estimated capital and operating cost have been obtained.

Jan 1, 1991

By R. Hogg, M. Polat, S. Chander

A fresh dust generator was designed and built in order to study the agglomeration behavior and other characteristics of freshly generated airborne dust. The size distribution of the freshly generated quartz airborne dust produced by the generator was measured both directly in air and after dispersion in water. It was observed that same dust particles had an apparently coarser size distribution in air than in water, suggesting possible agglomeration of the dust particles. It was also observed that the size distribution obtained by a cascade impactor was very similar to the liquid dispersed size distribution, implying deagglomeration by the impactor. The agglomeration was confirmed by microscopic observations of particles in air and those collected on a microscope slide. The extent of agglomeration played a decisive role on the fraction of the dust actually becoming airborne. It was also found that contamination of the airborne dust by the rolls of the crusher was almost twice as much as that of the product.

Jan 1, 1991

By Gerald A. Zicg

The Sheep Creek project area lies between 15 and 20 miles north of White Sulphur Springs in west central Montana, on the southern flanks of the Little Belt Mountains. The Sheep Creek project is a joint venture in which Cominco American Resources, Inc., has a 50% operating interest and BHP-Utah International, Inc., has a 50% participatory interest. The property consists of over 40,000 acres of leased fee land and lode claims. Modern exploration of the Sheep Creek area began in 1973 and 1974, when Homestake Mining Co. examined the extensive Sheep Creek gossans with soil sampling, trenching, and drilling. Cominco American Inc. began exploration in the area in 1976. Between 1978 and 1985, Anaconda Copper Co., Exxon Minerals Co., and Freeport also conducted exploration programs in the area. In 1985, Cominco completed consolidation of the district, gained BHP-Utah International, Inc., as a joint venture partner, and the joint venture drilled the first significant copper mineralization on the property. Of six bodies of copper mineralization so far located, the best defined are an upper copper zone, which includes a probable resource of 4.5 million metric tonnes grading 2.5% Cu and 0.1 % Co, and a lower copper zone which includes a possible resource of 4.5 million metric tonnes grading 4% Cu. Exploration drilling of the property is in progress.

Jan 1, 1991

By G. E. Wasson

Consolidation Coal Co. tested the agglomeration of fine coal using a laboratory pellet mill. The principal operating variables examined were feed coal moisture, coal size distribution, and additives to the feed coal. The moisture of the feed coal was found to be critical to both the pellet mill operability and the product strength. Coals, with feed moistures too high to pelletize, could be pelletized if mixed with lime or a water absorbent material. The addition of dry starch binder improved the product strength.

Jan 1, 1991

By Yoshiaki Numata

It is a matter of importance to use the lower alkyl monoethers of propylene glycol (polyPGME) as a frother in sulfide mineral flotation, for their compounds are highly soluble in water and are surface active frothers to some extent. The purpose of this study is to clarify fundamental roles of frothers in sulfide mineral flotation by investigating the effects of polyPGME on the floatability of galena with xanthate and adsorption property those ethers at the liquid/air interface. Fundamental investigation on the flotation of sulfide minerals using o,o-dialkyl dithiophosphates has been carried out through galena floatability tests in the following two cases:(l)single use of dithiophosphate for sulfide mineral collection and (2) joint use of dithiophosphates for its collection.

Jan 1, 1991

An integrated mining equipment development organisation is typified by Deutsche Montsn Technologic of Essen, Germany. working on improvements in reliability, production and control in coal mines. Examples of recent mining advances are in mechanised roadheading, in different approaches to cutting technology, and in low height roof bolting.On the longwall face the mechanics of cutting are related to supplied energy as well as to dust make. In conveying both armoured face conveyors and conveyor belts are monitored. Roof support is not neglected and the continuous pumping of stowage slurries provides further options for longwall support. Surveying developments, particularly the gyro-theodolite, directional drilling. and shaft vehicle monitoring provide further examples of advances in control in coal mining activities.

Jan 1, 1991

By Victor F. Hollister

This section includes examples of discoveries of Kuroko- and Anyoz-type massive sulfides, and shale-hosted, zinc-lead deposits, and describes exploration models for each group of case histories. Exploration or empirical models can differ from genetic models, because ore guides and controls are emphasized in exploration models. Genetic models may form the scientific basis for exploration or prospecting models, although factors that are important to the localization of ore are stressed in exploration models. The paper by Sato (abstracted herein) on Kuroko deposits can be used as a general exploration guide for that type of deposit. It is clear, however, that no unambiguous stratigraphic control for Kuroko-type ore is given in the Sato paper. The paper by MacIntyre (an excerpt herein) describing Gataga, Midway, and Windy Craggy includes most of the elements of the shale-hosted and Anyox models. Although more recent work by the Geological Survey of Canada has modified the Windy Craggy stratigraphy, the Anyox model as applied to Windy Craggy is well described in the MacIntyre (1983) paper. Discoveries of ophiolite-, Ducktown-, volcanic-associated Ni- Cu-, and Besshi-type deposits are not included in this section. Conformable massive sulfide deposits are generally assumed to be syngenetic. Sulfides in the crosscutting feeder zones, however, are classed as epigenetic. Therefore, volcanogenic massive sulfides can contain both a syngenetic and an epigenetic component. Vital to the development of the epigenetic component is a heat source that propels the convection cycle that forms both components. In all massive sulfide discoveries described in this section, it is assumed that a volcanic magma fueled the hydrothermal fluids.

Jan 1, 1991

By J. David Lowell

The discovery of the Kalamazoo (Arizona) ore body was a comedy of errors and coincidences and luck -as most discoveries probably are. The story began in early 1965 when Quintana Petroleum decided to diversify from petroleum into minerals and decided to do this by the route of minerals exploration. Quintana Petroleum is owned by the Cullen family of Houston and has Geen successful over the years in discovering oilfields. In 1965, the president and general manager was Corbin J. Robertson, son-in-law of Harry Cullen, founder of the company and a famous Texas wildcatter. But, in 1965, Quintana's financial advisors suggested that the company go into several mineral commodities, including copper, with Tucson, AZ, as the jumping-off point for copper exploration, and with a geological consultant (me) as the point man. The stage was now set! (See Fig. 1, location map of the San Manuel District, Arizona.)

Jan 1, 1991

By J. H. Gasper

The overall success of steep slope (>20°) contour mining is dependent upon many factors. The major factor is the selection of the mining method that best suits the premining site conditions both environmentally and economically. These conditions can be divided into three major categories: 1) Geometric Conditions --machine limitations, slope stability restrictions, erosion capacity, among others; 2) Physical Conditions--material properties, rock strengths, diggability, driving surfaces, among others; 3) Chemical Conditions --acid/base relationships, blending or selective placement of overburden, among others. This paper incorporates these conditions through conceptually modeling compliance oriented contour mining methods; in particular Haulback methods, utilizing: 1) the Front-End Loader (FEL)/Truck; 2) Tractor Scrapers; and 3) Combined FEL-Truck/Scraper. Engineering analyses including machine selection, sequencing, ease of varying production rates, slope requirements (for stability and running surfaces), drainage requirements and many others can be performed after the geometric constraints dictated by in-situ conditions and regulatory requirements have been conceptualized. Once all generalized geometries have been established, reduction to idealized three-dimensional views is achieved. These are then reduced to two-dimensional symbolic models, mainly plan views, but also elevations and sections. Equipment activities and operations are then conveniently overlayed. Without this simple two-dimensional reduction, technology transfer remains awkward and non-analytical.

Jan 1, 1991