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By L. Xiao

Using K-oleate as a collector and alizarin red S (ARS) as a modifying agent, selective depression of dolomite from francolite was achieved in alkaline medium (pH> 9.0). Interestingly. ARS was also found to depress igneous apatite in alkaline medium in oleate flotation of apatite and calcite. Adsorption of ARS alone on dolomite was found to be higher than that on francolite. Complimentary adsorption experiments of ARS and K-oleate showed that oleate adsorption was increased in the presence of ARS on francolite but not on dolomite. K-oleate adsorbs on both francolite and dolomite and causes precipitation of calcium and magnesium oleate. Such precipitates can be pre-vented when ARS is present. The results are explained in terms of competitive adsorption for the active sites on francolite and dolomite by oleate and ARS, and their interactions with dis-solved mineral species in solution.

Jan 1, 1988

By A. B. Cecala

The Bureau of Mines has developed a pallet loading dust control system designed to lower the dust exposure of workers during the bag stacking process at mineral processing facilities. The system makes bag stacking much easier because the pallet height remains constant throughout the entire bag stacking cycle through the use of a hydraulic lift table. The system uses a push-pull ventilation technique to capture the dust generated during bag stacking. A low-volume, high-velocity blower system operating at approximately 150 cfm blows a stream of air over the top layer of bags on the pallet. The blower system is composed of two 3-in air jets (approximately 1,200-ftjmin velocity) directed toward an exhaust system on the opposite side of the pallet. As these air jets travel across the pallet, they entrain the dust generated during bag stacking. The exhaust ventilation system pulls approximately 2,500 cfm of air and dust through the exhaust hood. This exhaust air can then be dumped into a baghouse ventilation system, or filtered before being discharged outside the mill. During a laboratory evaluation, a 70-pct dust reduction was recorded for the bag stacker. The system was then evaluated in an actual working environment. The first field evaluation was performed at a silica sand operation in which one worker performed the entire loading and bag stacking process. This worker's dust exposure was lowered 76 pet when using the new pallet loading system. The second field evaluation showed only moderate dust reduction, but this was mainly attributed to an overriding problem associated with background dust and the cleanliness of the bags. From both the ergonomic and production standpoint, the system was well received by both the workforce and plant management.

Jan 1, 1988

By Dundon P

The Broken Hill Proprietary Company Limited (BHP) is Australia's largest company with widespread commercial interests ranging from steel productin to minerals, oil and gas recovery. While these interests are worldwide, the Company operates or is partner in more than 30 Australian mining ventures. BHP Engineering (BHPE) is the in-house consultant to BHP but is also the largest consultancy in Australia available to general industry. Australian Groundwater Consultants Pty Limited (AGC) is a large, independent consultancy offering specialist services in all aspects of water resources, waste management and environmental engineering, both in Australia and overseas. AGC is particularly well regarded within the mining industry and has a considerable record of providing solutions for mine water related issues. By drawing on the extensive combined experience of AGC and BHP Engineering, this paper will summarize some of the unique ways in which water interacts with and impacts on mining operations in Australia, particularly in matters such as: Slope Stability Drainage and Dewatering Production Cost (Transport, Drilling, Blasting, etc) Water Supply Water Management Tailings and Waste Management Environmental Issues. The paper will also illustrate the cost benefit of providing major engineering works for reduction in total mining cost. It will be shown that, through advance planning and close interaction between outside experts (ie consultants) and on- site personnel, very significant operational cost savings can be made while at the same time achieving a safe and responsible mining environment.

Jan 1, 1988

By Ronnie W. Sisk

1. Troubles start early - Inadequate Geotechnical Data A. Owners think they are saving money by allowing limited soil borings at their site. This places a high gamble on the bidders and the Lump Sum Price will be higher. B. Inaccurate elevations on soil reports. a. Surprises in depths - over or under design bid bottom elevations. 1. Requires backfill and extraction of casing that is too short for the greater depth of the drilled shaft. 2. Redrill utilizing longer casings. 3. Softer earth (backfill) can cause difficulties in redrilling such as less quantity extracted on the auger and maintaining plumbness. 4. Greater concrete overrun. b. Extreme under depths. 1. Excessive concrete is placed as a result of planning for a deeper shaft. c. Geotechnical report that does not supply a layout of boring locations. d. Design Engineer does not have a basic knowledge of how a caisson is installed.

Jan 1, 1988

By Bengt H. Fellenius

THIS PAPER deals with the analysis of results from axial testing of vertical single piles, i.e. the most common field test per-formed. Despite the numerous tests which have been carried out and the many Papers which have reported on such tests and the analysis thereof, the understanding of pile test loading in current engineering practice leaves much to be de-sired. The reason for this is that the engineers have concerned themselves with mainly only one question: "Does the pile have a certain least capacity?", finding little of practical value in analysing the actual capacity and the pile-soil interaction. This Paper aims to show that engineering value can be gained from elaborating on a pile test ? during the actual testing in the Held, as well as in the analysis of the results. The first portion of the notes make use of an earlier Paper by the author (Fellenius. 1975). However, additional views and recent literature have been incorporated.

Jan 1, 1988

The Que River and Hellyer polymetallic massive sulphide ore bodies are located 3 kilometres apart in the Cambrian Mount Read volcanics of Western Tasmania. Both deposits are classic examples of the Kuroko volcanogenic style. Base and precious metal rich hydrothermal solutions rose through a deep fracture system and vented on the sea floor, causing sulphides to accumu- late in adjacent topographic lows. Together the preproduction geological resource is approximately 23 million tonnes at greater than 18% zinc plus lead, with economically significant silver and gold. Exploration by Aberfoyle in the Mount Read volcanics com- menced in 1970. Que River was discovered in 1973 following a comprehensive data review, a regional stream geochemical survey and a helicopter-borne electromagnetic survey. Production began in 1981, and the mine is currently producing 300,000 tonnes per year. The ore is sold to the Electrolytic Zinc Company of Aus- tralasia Ltd mill at Rosebery. Ten years of extensive geological mapping, soil geochemistry, and induced polarisation, combined with continual study of the Que River orebody and its host rocks, formed a strong frame- work for the discovery of the Hellyer deposit, which was found as a result of drilling .a subtle time domain electromagnetic anomaly in 1983. Hellyer is currently being mined at a rate of 250,000 tonnes per year, with the ore being concentrated at Aber- foyle's converted Cleveland tin mill. Treatment of 1 million tonnes per year will begin in early 1989 at a new mill located near the Hellyer site.

Jan 1, 1988

By G. Macfarlane

"In 1985, a crushing plant, located in the feed preparation area of Kidd Creek's copper smelter, was modified. The plant, which originally had treated only copper-bearing materials for the smeller, at a rate of 10 tonnes per hour, was expanded to 40 tonnes per hour capacity and modified to treat silica ores to meet the smelter’s flux requirement and also gold ores from the company's Hoyle Pond property. In the storage area adjacent to the crushing plant a 300 tonne per day gold mill was constructed.This paper outlines the construction and first year of operation of the crushing plant and gold mill with emphasis placed on the capital and operating advantages to be gained by utilizing an existing metallurgical infrastructure.IntroductionThe Kidd Creek Mines Ltd. copper-zinc-silver orebody is located 24 km north of Timmins, in Northern Ontario . Mining of this massive sulphide de posit commenced in 1966 and, in the ensuing years, a concentrator and zinc plant were constructed at the metallurgical complex, approximately 17 km by rail from the mine site . At this same site, in 1981, a copper smelter and refinery were commissioned. The smelter which utilizes the Mitsubishi smelting process for the continuous production of blister copper from copper concentrate, has been comprehensively described in previous papers.At the time of the smelter construction, a small (10 tonnes per hour) crushing plant was installed in the smelter's feed preparation area. This plant was used to treat the copper-bearing revert material produced by the smelter, and, apart from periods when slags and matte were produced through furnace drainage at the end of each operating campaign, it was generally under-utilized. This fact, together with the requirement to devise a more cost effective method of providing silica flux for the smelting operation, was the basic rationale for modifying and expanding and crushing plan t. At the same time, development at Kidd's Hoyle Pond orebody had progressed to such a stage that a gold mill of 300 tonnes per day was warranted."

Jan 1, 1988

By L. J. Cabri

The level of mineral exploration activity for platinum in recent years, especially in North America, has ranged widely. Exploration programs have been based on a variety of ore deposit models and deposit types. These range from the classic magmatic model for sulfide/oxide deposits and their associated placers, through hydrothennal models for bonanza-type deposits, to low-grade mineralization potentially amenable to lower cost bulk mining methods. The platinum-group element (PGE) distribution in these different deposit types is not well-known however, and PGE determination is fraught with analytical difficulties. To properly assess a prospect or to achieve effective recovery by mineral processing, it is important to determine the mineralogical distribution of the PGE.

Jan 1, 1988

By K. G. Wallace

In 1982, the US Congress passed the Nuclear Waste Policy Act (NWPA) to provide for the development of an underground repository for spent nuclear fuel. This development will be managed by the US Department of Energy. In 1986, the President selected three areas for site characterization to determine their suitability for the development of an underground repository. Those sites were: (1) a site in volcanic tuff located at Yucca Mountain in Nevada, (2) a site in bedded salt located in Deaf Smith County in Texas, and (3) a site in basalt located in Hanford, WA. At present, conceptual repository designs are being developed for each site. A key element of a repository design is the underground ventilation system required to support construction, nuclear waste emplacement, and potential waste retrieval. This paper describes the preliminary ventilation system designed for the repository in tuff. The concept provides separate ventilation systems for the construction and waste emplacement activities. The paper further describes the means by which acceptable environmental conditions will be reestablished to allow reentry into previously closed rooms for the purpose of inspection, maintenance, or retrieval.

Jan 1, 1988

By Murdaugh W

The application of photogeological techniques and analysis of more advanced remote sensor images can be a cost and time effective tool in the search for desert placer gold deposits. Examples are given of regional analysis using standard false color composit Landsat images and conventional black and white aerial photography. The examples include identification of sites to sample to evaluate the pathways of .alluvial gold migration and identification of potential sites of concentration. The results of these studies developed an increased number of target areas and exploration in proceeding with promising results. In addition to the development of additional target concepts and identification of specific target areas data useful to evaluation of mineability can also be obtained from photogeological investigation. Some indication at least can be obtained of the existence of duricrusts and salines that may hamper mining. Identification of possible sources of water is another important task in the desert environment. In addition indications of the clay content of the material to be worked is very important because of its economic impact on operational costs and overall recovery. The application of photogeology to these questions is discussed.

Jan 1, 1988

By M. Fujikawa, S. Goto, M. Nishikawa

"The semi-pilot scale plant for injection smelting of zinc calcine was operated under the committee of Joint Research Organization of Injection Metallurgy. The capacity of the plant is 10 ton metallic zinc per day. The plant was designed by the resul ts of basic and bench scale tests of the capacity of 1 ton metallic zinc per day which was published at ""Zinc '85"". The equipments of the plants, operational conditions, results of the operation such as recovery of zinc in injection furnace and condenser, combustion rate of powdered coke and consumption of energy in this process are presented in this paper. The results of the study of the feasibility of the commercial plant of 100,000 ton zinc per year by the injection smelting are also discussed in the paper. IntroductionThe research committee of new smelting process of zinc by injection was established in 1981 under the finantial support of Mining Promoting Foundation of Japan. Six zinc producing companies joined in this organization. The price of zinc was very low at that time and the energy cost, especially, cost of electric power in Japan was extremely high. Invention of a new economical process for zinc extraction had been stronglydesired. The author proposed a injection smelting of zinc as a economical process in energy saving after a calculation of thermodynamical equilibrium and heat balance(1 )(2).The research committee has been studying the injection process since 1981. The small basic experiment by using a crucible furnace was carried out from October 1981 to March 1983 and the reaction of reduction of calcine by injection smelting was ascertained (2). Vaporizatipon of zinc and behaviours of impurities were examined. After the basic experiment, the bench scale test with the production capacity of zinc of 1 ton per day was carried on from November 1983 to October 1984.The bench scale tests were carried out to obtain the proper design of feeding devices of calcines and coke into a furnace and also to obtain fundamental data for enlargement of this smelting process(3,4). The recovery of metallic zinc in this small equipments was about 50% and main loss of zinc was formation of dross in the condenser."

Jan 1, 1988

By David A. Lipton

In the summer of 1985, at the request of the U.S. Forest Service, the U.5. Bureau of Mines examined the 109,000-acre West Big Hole study area to evaluate its identified mineral resources. The study area is in Beaverhead County, about 50 mi west of Dillon, MT. Four lode properties within or adjacent to the study area contain an estimated 452,000 tons of identified subeconomic gold-silver resources. Resources ranged from 900 to 302,000 tons, with estimated grades between 0.02 and 0.23 oz/ton gold and as much as 4.8 oz/ton silver. Gold, silver, and base-metal content in samples of poorly exposed mineralized structures indicate that exploration may identify resources on 18 additional lode properties within the study area and 5 properties adjacent to it.

Jan 1, 1988

By H. N. Maleki

Extensive measurements and underground observations in three Western U. S. coal mines are integrated in this paper to determine in-situ pillar load-deformation characteristics for narrow (30 it wide, 80 ft long) pillars in two-entry gate road systems. In spite of similarities in the regional geology, coal pillar laboratory mechanical properties and gate pillar geometries, the pillar peak strength, post-failure behavior, and failure mechanism were shown to be significantly different. Pillar peak strength was shown to be dependent on depth at one site, approaching burst-prone stress levels of 4000 psi. At another site, the pillar peak strength was lower because of lower confinement; this was related to the higher frequency of cleats and the lower friction- al properties of the roof/floor and coal contact. Two failure mechanisms were identified - one in the pillar, and the other in the mine floor. The roof stability was good at all three sites because of the thick-bedded nature of the roof strata and limited total gate span in a two-entry system. Existing pillar design techniques were shown to be inadequate for design, requiring adjustments for depth of cover, cleat frequency, and roof /floor frictional properties.

Jan 1, 1988

By S. Ford

The introduction of recent advances in molecular biology into the field of microbial ecology has made available a powerful set of analytical tools for dissecting the structure of microbial communities in natural environments. The use of these approaches, many of them based on DNA-DNA hybridization enables the researcher to assess the occurrence of specific DNA sequences among the natural bacterial flora (Ford and Olson 1987). These techniques promise to have wide application as tools for monitoring the spread of introduced microorganisms (Trevors, 198'): Ford and Olson. 1987) and have been used to examine the response of bacterial communities to environmental contaminants and stressors (Barkay and Olson. 1986. Olson and Ford. 1986. Olson. Ford and Lester 1987) The occurrence of heavy metal resistance among microorganisms has been discussed as a possible tool for the detection of pathfinder elements employed in mineral exploration (Olson and Barkay 1986). In addition, the occurrence of heavy metal resistant bacteria may be utilized in protocols for assessing the occurrence and biological impact of contamination occurring as a consequence of mining operations. In this context the use of DNA hybridization technology enables the investigator to directly quantify the number of heavy metal resistant bacteria by the use of genetic probes specific for those resistance genes. The implementation of a strategy for detection of heavy metal resistance genes by hybridization technology is dependent on the availability of data on the genetic systems which encode resistance The availability of extensive DNA sequence data on mercury resistance genes (Brown et a11986. Barrineau et al 1984) has lead us to use gene probes specific for mercury resistance within natural bacterial populations as a model system for investigating the response of these bacterial populations to the occurrence of mercury In the environment.

Jan 1, 1988

By M. Moinpour, E. Liao, C. Y. Aw, D. J. Brown, P. W. Cheung

"Currently, silicon-based insulated-gate field-effect devices are being widely developed as the basic structural elements in a new generation of chemical microsensors. In this paper, we discuss some of the process considerations related to the fabrication of the Chemically Sensitive Field-Effect Transistor (CHEMFET). This ion-sensitive CHEMFET (or ISFET as it is often called) can be used for pH measurements (i.e., as a pH sensor) when the gate insulator of the electrolyte/insulator interface is made of Si3N4 obtained by the LPCVD method. Effects of processing parameters such as the Si3N4 deposition rate, gas composition, total flow rate, annealing treatment, etc. on Si/Si02, Si/Si3N4 and Si/Si02/Si3N4 structures are discussed in relation to the CHEMFET fabrication. Their effects on the electrical characteristics and chemical response of the sensor are also examined. Capacitance-Voltage (C-V) measurements and ESCA analysis have been used to interpret the results. The Si3N4/Si02 double dialectric layer provides improved ion blocking for the gate insulator in electrolyte solutions with enhanced pH sensitivity over time. The stability and performance of the fabricated CHEMFET sensors were tested by measuring the pH sensitivity in various storage conditions. The SEM analysis was used to evaluate the hydration effect at the ISFET's gate insulator with respect to different storage conditions.IntroductionThere has been a continuous interest in the development and fabrication of various chemical microsensors for chemical and biomedical applications over the last fifteen years. The application of semiconductor (particularly silicon) technology to the area of sensor fabrication has led to an emergence of a new generation of miniaturized, microelectronic, solid-state chemical sensors. There are numerous clinical situations where continuous monitoring of body electrolytes concentrations such as Na+, K+, Ca+2 , etc. and blood gases (pH, Po2 , and PC02) would be essential for the effective diagnosis and management of patients under critical conditions. Solid- state microsensors can be used for direct and continuous in vivo measurement of the above parameters in most instances."

Jan 1, 1988

By N. S. Dalal, X. Shi, V. Vallyathan

"Electron spin resonance (ESRJ spectrum of the hydroxyl (· OH) radical spin adduct with .the spin trap 5,5-dimethyl-1-pyrrolintt-N-oxide has been obtained in suspensions of freshly ground quartz particles. The concentration of the spin adduct (and hence of the • OH radicals) increases with the amount of grinding. The dust's potential for the generation of the· OH radicals is maximum when fresh (i.e., immediately after grinding) and decreases to 50% in about a day on storage in air. Studies involving metal chelates .indicate that the • OH radical formation involves mainly the silica surface and H20 rather than the Fenton reaction. The results suggest that hydroxyl radical reaction(s) could be important in the lipid peroxidation and fibrogenicity by quartz dust, particularly .in acute silicosis. INTRODUCTIONIn this paper we report on our electron spin resonance (ESR) detection of the formation of hydroxyl (·OH) radicals in aqueous suspensions of freshly crushed quartz particles. This work was undertaken with a view to find possible clues to the role of free radicals in the pathogenesis of quartz-induced fibrogenicity, commonly known as silicosis. We noted that while silicosis is one of the major health hazards in coal and mineral industries, the mechanism by which the quartz particles exert their toxic action on cells and the process(es) by which these actions progress to fibrogenesis are still poorly ·understood (Reiser and Last, 1979; Singh and .Rahman, 1987). It is generally thought, nevertheless, that the action of quartz particles on the biological membranes is the starting point of the silicotic process (Parazzi et - al., 1968). A possible clue to the mechanism of the membrane damage by quartz particles, in terms of the role of oxygenated free radicals, is suggested by the following observations. A suspension of quartz particles in contact with alveolar macrophages has been reported (Gabor et al., 1975; Koike et al., 1982) to initiate an enhancement of lipid peroxidation, defined broadly as the oxidative deterioration of polyunsaturated components of lipids. Hydroxyl (· OH) radicals are known to be capable of peroxidation by abstracting hydrogen atoms from cell-membrane lipids (Halliwell and Gutteridge, 1985) and of initiating lipid peroxidation in lysosomal membranes. (Fong et al., 1973). Arong other lines, it is known that exposure of cell membranes, fatty acids, and unsaturated food oils to ionizing radiation, which generates· OH radicals, causes rapid peroxidation (Halliwell and Gutteridge, 1985). Thus • OH radicals (and also other oxygenated species such as Oi, 10 2, and H20 2) might be expected to play a role in the toxicity of quartz. Earlier studies of the aqueous chemistry of quartz suspensions have reported detection of H2O 2 (Kalbanev et al., 1980), implicating the formation of ·OH radicals as transient species. However, we are not aware of any report of the detection of • OH radicals in quartz reactions, and thus the present study was undertaken. Since it-is known that, because of their high reactivity (hence short lifetime) in aqueous media, the • OH radicals cannot be detected via ESR directly (Finkelstein et al., 1980; Buettner, 1982) we have used .ESR combined with the spin-trap methodology (Finkelstein et al., 1980) for studying the· OH formation. The results show that· OH radicals are indeed formed in aqueous suspensions of freshly ground quartz; thus pointing to ·a possible new clue to the cytotoxicity of freshly formed quartz particles and thereby to silica fibrogenicity."

Jan 1, 1988

By J. E. Shearer

The state of Arizona produced 253,276.2 metric tons (279,000 st) of crude gypsum during 1986. This represents approximately 1.7% of the total U.S. production. Four mines provided Arizona's gypsum, three of these mines are in the San Pedro Valley. The uses of the gypsum produced in Arizona are for manufacture of cement, agricultural uses, and wallboard manufacture. The gypsum is used as a retarder in the manufacture of Portland cement. The use in agriculture is treatment of alkali soils to allow water penetration. Other deposits in the San Pedro Valley have production potential, providing there is sufficient market for additional wallboard. The author completed an evaluation of one property earlier this year.

Jan 1, 1988

By Paul W. Jeran

Subsidence over a series of longwall panels undermining sloping terrain in southwestern Pennsylvania was monitored to verify the Bureau of Mines subsidence prediction model for the northern Appalachian coal region. Comparison of the field data to model output shows close agreement. Vertical movements over each panel ceased with the mining of the adjacent panel. Horizontal movements were significantly affected by topographic slope. The distribution of horizontal strains over each panel were similar, with a zone of compression occurring over the center of each panel. The zones of compression were flanked by zones of tension toward the rib. The magnitude of the tensions were affected by the slope. The strains developed at the completion of each panel were not significantly altered by the mining of subsequent panels.

Jan 1, 1988

By James R. Boyle

The Bureau of Mines initiated a program to address short-and long-term objectives of wetlands restoration as a option for reclamation of lands mined for phosphate. The short-term objectives were to identify a suitable wetland test site, initiate an extensive premining monitoring plan, develop an acceptable mining plan, and recontour and revegetate the test site. These goals were accomplished using a unique combination of expertise provided by Federal and State agencies and private industry. A 6.5-ha forested wetland with an associated streambed was offered by private industry as the test site. A premining monitoring program was established and carried out from May 1982 to October 1983. A control site was established to determine ecological changes unrelated to mining. Clearing and mining began in October 1983 and was completed in April 1984. Grading and streambed restoration was completed in February 1986. Revegetation of the site was completed in February 1987. The program to meet the long-term objective of postmining monitoring is described.

Jan 1, 1988

By R. E. Nelson

The Alton Coal project, located in south-central Utah, lies at one point just over six miles from Bryce Canyon National Park. This region of the southwestern United States has been called the "Golden Circle" of national parks and monuments. Can a mine be inserted into this region so that it does not intrude on this spectacular landscape? The Alton Coal Project is a proposed surface coal mine designed to serve as the fuel source for the Harry Allen Power Plant, a 1,000 megawatt generating station planned for a site 25 miles northeast of Las Vegas, Nevada. The mine and the power plant will be connected by an underground pipeline through which coal will be transported in slurry form.

Jan 1, 1988