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By Kidd CH

The excavation of a coal mine or any other mine, tunnel, or quarry, below the water table establishes a void towards which ground- water will flow. Inflows into the mine, if significant, can cause not only problems such as flooding, and/or muddy floors, in the mine, but commonly also require disposal of poor quality groundwater. The flow of groundwater towards a mine is accompanied by a decline in groundwater levels, which may extend up to several kilo- metres around the mine. This may seriously effect vegetation, stream flow and existing users of groundwater. At the pit face groundwater gradients can also cause slope stability problems and where a water table is intersected, increase blasting costs.

Jan 1, 1983

By Rick A. Croote

The objective of the Cerrejon Coal Project is to mine and export a minimum of 15 million metric tons per year of bituminous coal from the Guajira Pennisula in Colombia, South America. Major components of the project will include an open pit mine, 150 km railroad, marine terminal for storage and shipping, and accommodations for the support personnel. This paper primarily reviews the coal handling facilities at the mine and port which will include crushers, conveyors, silos, stacker/reclaimers, and a shiploader. Of special interest is the design concept for unloading bottom-dump railcars, a programmable controller control system with automatic stacking and reclaiming, a linear-type shiploader, and 2.4m wide conveyors running at 5 m/sec.

Jan 1, 1983

By Kenneth M. Reim

In 1971, United States Borax & Chemical Corporation (U.S.Borax) initiated a mineral exploration program on federal lands in Southeast Alaska, with the commitment that any possible development would be done with great care for the environment. This program resulted in the discovery of a molybdenum deposit and the location of mining claims in 1974, in an area 45 miles east of Ketchikan, now called the Quartz Hill Molybdenum Project (Figure 1). At the time of this mineral discovery, the area was part of the Tongass National Forest, managed by the Forest Service, United States Department of Agriculture, and open to mineral entry and multiple use. In late 1978, the area was designated Misty Fjords National Monument and closed to mineral entry, and in late 1980 the area surrounding Quartz Hill was classified as Wilderness. These new laws and regulations, as well as the special interest environmental groups which oppose resource development, have significantly delayed and increased the costs of developing Quartz Hill.

Jan 1, 1983

By T. A. Ring

The bed filtration of colloidal particles has been modeled by performing a differential particle balance. The balance considered the localized particle deposition rate to be the sum of three rate resistances: 1) mass transfer to a region near the surface; 2) adhesion onto a partially filled surface; and 3) resuspension from a partially filled surface. The differential particle balance equations, one for the free particles and one for the adhered particles, were solved by a finite difference algorithm. The results of this model are compared to experimental filter breakthrough curves.

Jan 1, 1983

By Larry R. Fletcher

A misfire results when explosives fail to detonate as planned during a mine blast. Accidental detonation of misfires is a frequent cause of personal injury, equipment damage, and lost production. In an effort to minimize these problems, the Bureau of Mines investigated the causes of misfires, methods for detecting misfires, and procedures for their disposal. During this investigation, input was obtained from explosives suppliers, mining companies, blasting contractors, blasting consultants, and governmental agencies. Additional data were obtained through detailed analysis of blasting accidents involving misfires.

Jan 1, 1983

By Daniel L. Ng

This Bureau of Mines report describes the results of scanning electron microscopic (SEM) studies of the combustion residues of carbonaceous dust particles resulting from explosions and thermal ignitions in laboratory and full-scale mine tests. The dusts studied varied widely in rank and volatility: Pittsburgh seam bituminous coal (35% volatility), Pocahontas seam bituminous coal (16% volatility), anthracite (7% volatility), graphite, and diamond. The most systematic explosion studies were performed in an 8-L chamber with narrow size distributions of Pittsburgh coal dust with surface mean diameters of 2, 22, and 84 pm. Experiments were conducted mainly in air, with some data obtained in 50% 02. Observations of the bituminous coal explosion residues showed particles with rounded edges, particles with blowholes, and some cenospheres. The lower volatility dust residues showed fewer changes from the original, unburned dust. In addition to the experimental studies, results of SEM observations of residues from a mine explosion disaster are reported. Comparison of such residues with those from the laboratory and experimental mine explosions can help investigators determine the extent of dust participation in the disaster and in identifying the possible ignition sources.

Jan 1, 1983

By Robert J. Garino

Around two-thirds of world silver mine production comes from mines where the majority of ex-mill revenue is obtained from other metals. In this talk I will illustrate the importance of this output of silver as a by-product of the mining of various base metals. I will also consider the impact of relative changes in base and precious metal prices on mill-head revenue, and therefore, on production decisions. During the latter half of 1982 improving silver prices encouraged re-openings at several base metal mines. Thus some production of lead, zinc and copper can be regarded as partly conditional on the prevailing silver price. Conversely, a good deal of silver production can be considered to be independent of the silver price and dependent on the production of some base metal. It is the degree to which the value of silver mined affects the revenues of nominally, base metal, producers that is the central concern of this presentation.

Jan 1, 1983

By Robert B. Parsons

"Although the April 19, 1983 federal budget appears to put greater emphasis on new or expanded government spending programs in an effort to get Canadians working again, the budget proposals contain a light sprinkling of tax changes which could be of some direct benefit to the mining industry.This month, Tax Notes examines some of the more important of these changes.IntroductionSome sectors of Canada's mining industry could benefit from the proposed income tax changes announced by Finance Minister Lalonde in delivering his budget address to the House of Commons on April 19, 1983. Improved depletion allowance rules, expanded investment tax credits, better use of business losses, and inflation proofing of personal capital gains on Canadian common shares are all part of the measures included in Mr. Lalonde's first budget to try to reinvigorate the battered Canadian economy.Improved DepletionUnder the Income Tax Regulations, a taxpayer who incurs Canadian exploration expense (and certain other eligible expenses) is permitted to deduct not only the full amount of the Canadian exploration expense (""CEE""), but also an additional allowance (the so-called earned depletion allowance) equal to one-third of the CEE. Thus, a taxpayer in certain circumstances can claim a deduction of $1.33 for each $1.00 of eligible expenditure, including CEE.Although CEE can be deducted from any source of the taxpayer's income (for example, from investment income, salary income, and so on), prior to budget date the earned depletion allowance was deductible only from the taxpayer's resource profits. This restriction on the deductibility of the earned depletion allowance substantially reduced the attraction of the allowance: few individual investors or investment companies, for example, have the required stream of resource profits, at least when the CEE or other eligible expenditure is made."

Jan 1, 1983

By Rodger C. Smith

The topic chat has been assigned to me ?Economic and Political Climate of the Potash Industry? is a function of two basic facts: 1. Potassium is absolutely essential to plant and animal growth. Along with nitrogen and phosphorus it is one of three major plant nutrients, the three nutrients required in largest quantities for plant growth. 2. United States is unequivocally an "have not" nation with regard to potassium. Quantity of potassium ores is limited and, more disturbing, the cost of production at all U.S. potash mines is marginal in comparison with the major producing countries, i.e. Canada and U.S.S.R.

Jan 1, 1983

By Thomas J. Peters

During the 1982 Bureau of Mines study, 55 lode and 17 placer claims were held in the RARE II area. An estimated 150 lode claims and 50 placer claim, have been located in the study area; five were patented. There are no mineral leases. Gold has been produced from 8 lode mines and stream gravels have been worked for placer gold at 4 sites. Two suction dredges were active in stream gravels, but no significant gravel bars are identified. Identified mineral resources in the Weaver Bally area are gold and byproduct silver. The identified resources are at the Globe Mine, where approximately 33,000 tons of indicated marginal reserves (2,000 tons in the RARE II area, and 31,000 tons in the adjacent proposed Trinity Alps Wilderness) contain 0.45 oz gold per ton and probably 0.1 oz silver per ton. There are an additional 150,000 tons of inferred marginal reserves (35,000 tons in the RARE II area, and 115,000 tons in the adjacent proposed wilderness) averaging 0.38 oz gold per ton and probably 0.1 oz silver per ton. There is high potential for additional resources at the Globe Mine.

Jan 1, 1983

By Yoginder P. Chugh

This study has appraised available deeper soil loosening equipment in the 1-4 ft. depth range, in the U.S. and abroad which has potential for Illinois prime farm-land reclamation. The appraisal was based on written and/or oral contacts with equipment manufacturers, reclamation experts, and visiting with selected equipment manufacturers. The results indicate that several manufacturers in the U.S., West Germany, and England market static and vibratory deeper soil loosening equipment which may have potential for application in Illinois. The pertinent information concerning each equipment with potential is presented in this report.

Jan 1, 1983

By D. R. Lawrence

A one-day colloquium on the 'Selection of mining systems and methods' was held at Mintek, Randburg, on 21st September, 1983. The overall theme of the colloquium concerned the underlying reasons for the selection of a particular method or system of mining.

Jan 1, 1983

By Lucia Kuizon

The Miranda Pine Roadless Area Review and Evaluation (RARE II) study area (No. 5114) comprises 12,600 acres (5,100 ha) in Los Padres National Forest in Santa Barbara County, California, about 15 mi (24 km) east of Santa Maria (fig. 1). Mineral investigations are made by personnel from the U.S. Bureau of Mines on National Forest lands identified as Further Planning Areas in the RARE II program. The Bureau of Mines reviewed literature, mining claim records, and production files; examined the study area; and sampled mineral properties where appropriate.

Jan 1, 1983

By Robert B. Fulton

Commercially, celestite (SrSO4) is the predominant strontium mineral. Among other strontium-bearing minerals, only strontianite (SrCO3) occurs commonly; however, it is rarely an item of commerce. Production of celestite is principally in Mexico, Spain, and Turkey. An attempt to produce celestite in Canada was unsuccessful. The United States, which is wholly dependent on imports, chiefly from Mexico (99%), is the largest consumer of strontium. Lesser quantities are consumed in Japan and Europe. The Federal Republic of Germany is the principal source of strontium compounds imported to the US. Uses The principal uses of strontium are for the manufacture of strontium carbonate and nitrate. Carbonate is used in glass for TV tube face plates and in ceramic ferrites for magnets. Nitrate is used in pyrotechnics, mainly in safety flares, to which it imparts a characteristic brilliant red color. Minor amounts of strontium compounds are used in electrolytic zinc manufacturing where the carbonate is used to remove unwanted lead. Small quantities are consumed in greases, ceramics, soaps, alloys, and pharmaceuticals. Specifications Typical celestite specifications for the carbonate and nitrate markets are shown in Table 1. Specifications of manufactured carbonate, sold in two grades, one to the glass industry and the other for ceramic ferrites, are shown in Table 2. Both grades of carbonate are shipped in palletized 50-lb bags. Glass grade material is shipped in bulk by rail. [ ] Manufacturing Processes The following description is adapted from Anon. (1980) . The manufacturing process for strontium carbonate and strontium nitrate chemicals is conceptually simple. Strontium nitrate is made from strontium carbonate in two additional steps. The production process begins with celestite, the natural form of strontium sulfate. In the first step the ore is crushed, ground, and mixed with coke. This mixture is then fed into a kiln where the ore is reduced at high temperatures to strontium sulfide; the coke is added to the ore as a source of energy and carbon. The carbon combines with the oxygen [ ]

Jan 1, 1983

By Kenneth E. Skiff

INTRODUCTION United Nuclear Corporation and Homestake Mining Company are partners in a major uranium mining and milling venture near Grants, New Mexico. The partnership was formerly called Homestake-Sapin Partners and was recently renamed United Nuclear-Homestake Partners (UN-HP). The mill, originally built in 1958, had a capacity of 1,650 tons per day. With subsequent improvements and the addition of the adjacent Homestake - New Mexico Partners mill, the UN-HP mill is currently rated at about 3,500 tons per day. An alkaline type leach process is utilized by the mill. Milling consists of five basic steps: A. Ore handling and preparation B. Extraction C. Solid-liquid separation D. Precipitation and purification E. Product preparation MILLING Ore Handling and Preparation The primary source of ore for the UN-HP mill is from its four

Jan 1, 1983

By Larry R. Fletcher

The Bureau of Mines obtained blasting accident data from the Mine Safety ant Health Administration (MSHA), U. S. Department of Labor. These data were analyzed to determine the most frequent causes of accidents in mine blasting. Accident totals for 1971 through 1981 are tabulated for metal-nonmetal and coal mines both surface and underground. In the past 11 years (1971-1981, inclusive) there has been an annual average of 9 fatal and 121 nonfatal blasting accident victims. Underground mining averaged 6 fatal and 93 nonfatal injuries each year.

Jan 1, 1983

By Ellis G. Goree, George A. Simmons, Andrew B. Pervis

The pneumatic classifiers are widely used for fine dry powders separation These classifiers can be used for either the removal of fines from coarse feeds or the removal of coarse particles from ultrafine feed To optimize the operation of pneumatic classifiers, a thorough understanding of the impact of operational parameters on the efficiency of classification is essential This paper describes the design features and effects of operational parameters followed by illustrations of pneumatic classifiers usage in two case studies

Jan 1, 1983

By Kevin Connor

The mineral industry in Burundi was a minor contributor to the country's gross domestic product (GDP), which was estimated at just $1 billion for 19812. Coffee and tea continued as the Nation's major export commodities. Mineral exports consisted of small tonnages of wolframite, cassiterite, and baetnasite. Burundi's trade balance of payments situation worsened in 1981, with import payments more than double export revenues. Petroleum imports alone equaled 46% of the export revenue total. By year-end, the only indigenous fossil fuel source to have been found in Burundi was peat, which the Government had been attempting to develop to alleviate some of the petroleum import requirements. In June 1981 the Irish Peat Development Authority, Bord na Mona, signed a 4-year contract with the Burundian Government to supply technical staff for the ongoing peat project work there. Funding for the project was provided by the VS. Agency for International Development and the Government of Ireland. The new contract, which was an extension of ongoing peat research there, represented Burundi's increased awareness of the value of its large peat reserves for both energy and agricultural uses. At yearend, Burundi's Ministry of Public Works and Mines was does to selecting a contractor to study the feasibility of developing Burundi's phosphate deposits. The study would determine the potential for establishing fertilizer production facilities based on the country's phosphate reserves at Matongo-Bandaga, The study's specific objectives are to prove mineral reserve tonnage and grade, draw up mining and processing facility designs, estimate capital and production costs, and conduct a regional market and distribution survey. The cost of the study was estimated at slightly over $1 million, and it should take approximately 16 months to complete. The proposed project will mark the Burundian Government's first step in its plan to exploit on a large scale its natural mineral resources for advancing its agriculture-based economy. Burundi was dependent on imports, which are expensive to transport inland from coastal ports, to supply its domestic requirements for fertilizer. It was planned that part of the fertilizer production from the

Jan 1, 1983

By W. T. Reid

Analysis of the energy resources available in the United States confirms that coal will be needed to satisfy the future energy needs. The trends in the market place, particularly economic and political, suggest that the bulk of the coal will be consumed for generation of electricity. The utilization of coal to produce electricity will require technical solutions to the variable characteristics of coal and ash, development of methods to improve coal quality, and public acceptance of the cost of compliance with environmental standards.

Jan 1, 1983

Chalcopyrite concentrate was combusted in oxygen-nitrogen atmospheres, the composition of which ranged from 1-100 per cent oxygen. Factors studied included particle size, experimental temperature and oxygen concentration. The study was assisted by chemical and X-ray diffraction (XRD) analysis and temperature measurements of single particles. Size reduction occurring after melting was found to have a major effect on the overall reaction time. Thus time to attain ignition was largely determined by the original particle size, whereas combustion time was independent of this factor. For particles larger than 40 I'm in air the time to attain ignition predominated. The maximum temperatures measured for single particles were the result of pyrite present in the concentrate. Chalcopyrite did not attain thesame temperatures. Vaporization, either as CU(g) or CuO(g) lImited the temperature. Maximum temperatures measured for single particles of pyrite ranged from 1610°C in 14 per cent oxygen to 2360°C in 100 per cent oxygen (both at 700°C). Measured temperatures were compared with those calculated from a diffusion-based model.

Jan 1, 1983