Search Documents

The Racecourse Orebodies at Mount Isa consist of a series of parallel steeply dipping lead/zinc/silver orebodies with a strike length of up to 1000 metres. Production from these orebodies between 13 Level to 9 Level has been by a series of cut and fill stopes in two level stages, leaving a crown pillar at 11 level. Development of the 15 level to 13 level extraction stage has recently been completed. The layout consists of a series of parallel stopes over a strike length of 1200 metres. Access to the stopes is by two declines connecting the stopes with a series of crosscuts This paper describes the basic layout with development and production methods employed.

Jan 1, 1977

By William P. Diamond

A 3-inch pilot hole was directionally drilled to intercept the Freeport coalbed horizon horizontally at Mather, Pa., as part of a Bureau of Mines degasification project. The original concept was to continue the horizontal drilling into the coalbed, after the initial intercept, with a total of three horizontal holes eventually being completed. However, the erratic thickness (0.0 to 4.3 feet) of the Freeport coalbed at Mather was not sufficient to support the horizontal drilling degasification technique, and the site was abandoned after six attempts to locate adequate continuous coal thicknesses. The drilling of coreholes in the immediate vicinity of proposed well paths to evaluate coal thickness is essential prior to future slant hole operations. Although mechanical failures of the new directional drilling equipment, mud pump and rig breakdowns, directional control problems, and exploratory horizontal drilling in the Freeport horizon more than doubled the anticipated cost of the pilot hole, continuing improvements in directional drilling equipment and techniques should significantly reduce the time and costs of future drilling operations.

Jan 1, 1977

Allow miners to communicate via the pagerphone system when they are not near one of the phones. Approach A small lightweight pagerphone, having crocodile clips which pierce the phone line insulation, was developed. How It Works The Portable Telephone/Intercom is temporarily clipped onto an existing pagerphone line at any location, and operated like an intercom. It is riot necessary to strip the insulation from the pagerphone line to make the connection. In addition to the clips for connecting to pagerphone line, the Portable Telephone/Intercom consists of a small belt-carried control box, an ear-phone, and a bone-conduction microphone which is attached to the webbing in a miner's helmet. All together, these components weigh only 20 ounces including the batteries

Jan 1, 1977

This Bureau of Mines report summarizes the research, development, and evaluation demonstrations conducted by the Bureau of Mines under the Health and Safety Act of 1969 to improve the means of notifying miners underground, who are away from their own phone, that they are being called.

Jan 1, 1977

By R. L. Braun, D. L. Leach

Laboratory experiments simulating in-situ copper recovery from primary sulfide ores in sulfuric acid systems pressurized with oxygen are reported. Copper extraction and acid consumption data are correlated with temperature in the range 50 to 150°C and quenched pH in the range 0.25 to 2. Adverse changes in the chemical composition of the leach solution and the formation of gangue-mineral alteration products and secondary sulfides can severely limit the extraction of copper above 90°C. Keeping the pH below the self-buffered value of about 2 and the temperature below about 110°C produces the maximum extraction rates. Forcing the pH too low not only results in excessively high acid consumption but may also limit the extraction of copper at temperatures above 100°C.

Jan 1, 1977

By Wilbur L. Webb

An electrically powered methane sampling system for application on mining machines was designed, fabricated and laboratory tested. The system will sequentially draw sample air at a controlled rate from up to three machine positions across the mine face and deliver the air to either an approved methane monitor, methanometer or flame safety lamp. The prime considerations in the design were to provide an intrinsically safe, water and dust resistant control box and an explosion-proof power box capable of being operated from the various mining power sources. The power box contains an internal battery that provides operating power prior to mining machine start-up and alter machine shut-down. The internal battery is recharged automatically when mining machine power is available.

Jan 1, 1977

By Blair J. R

In the Bayer process, bauxite is leached with caustic soda, forming a solution of sodium aluminate, from which hydrated alumina is precipitated. The efficient operation of the continuous form of this process requires that the concentration of caustic soda be controlled. A computer simulation of the concentration of caustic soda has been conducted to provide information, regarding the dynamic behaviour of caustic concentration, which is not available from normal plant data. The basis of the simulation is a state- space model of an alumina refinery, linearized about the normal operating condition. The formulation of the model, with the relevant approximations and assumptions, is outlined. The simulation of the mudwash section of the. plant is described in detail. A continuous model of the mudwash, having time-varying coefficients, was driven using operating data from an alumina refinery. The modelled response showed reasonable agreement with the recorded plant response.

Jan 1, 1977

By V. L. Gravitis

Radioisotope X -ray techniques of analysis for nickel have been tested in laboratory and plant trials. In the laboratory tests. a comparison was made of radioisotope and conventional analyses for nickel in solid s samples taken from streams of a nickel concentrator. Coefficients of variation of 1.7% for feed and concentrate samples , and equal to 10% for final tailing samples, were obtained. Continuous determination of nickel in final tailing slurries was demonstrated in a trial lasting 20 days at a nickel concentrator (Western Mining Corporation), nickel being determined with a standard error of 0.036% Ni in the slurry solids within the range of 0.24 to 0.68% Ni. This error, obtained by comparison of on-stream probe analyses with assays of samples taken from the stream, includes errors in sampling and assay by conventional techniques.

Jan 1, 1977

Reduce spillage hazards and contamination when adding hydraulic nil to mining machine reservoirs. Approach An easily transported module, that delivers hydraulic oil directly into mining machines, was built and tested. How It Works The Hydraulic Oil Delivery Module is carried, from the oil storage area to the equipment needing oil, in the bucket of a scoop or other utility vehicle. Oil is pumped into the module reservoir from storage, or out of the module reservoir into the machine being serviced, through a long hydraulic hose. During long-term testing, the 115 foot long delivery hose made it possible to replenish the hydraulic oil in mining machines at the face with only limited interruption to the mining operation. (Figure 1 shows one! version of the module.) The compact Hydraulic, Oil Delivery Module consists of: an oil reservoir: a pump driven by a hydraulic motor; two high pressure, low volume oil lines, filters; and a low pressure, larger capacity delivery hose equipped with quick-connect-couplers. The high pressure oil lines are connected to the scoop's hydraulic power takeoff, which supplies the power to pump oil in or out of the module reservoir.

Jan 1, 1977

By R. P. Chapman

The geochemical interpretation of results of statistical analysis of published multi-element stream sediment data from southwest and northern New Brunswick is presented. Element concentrations in southwest New Brunswick are low and comparable to element concentrations in background areas in northern New Brunswick. Deposits of copper and nickel are indicated in southwest New Brunswick. Anomalous element concentrations occur in several areas in northern New Brunswick and the elements most commonly associated with these anomalies are Cu, Pb, Zn, As and Ag; and also Mo, Wand Sb. Bedrock geology greatly influences element concentrations and may cause false anomalies. Manganese has a pronounced effect on the dispersion patterns of Co and also Zn, Mo, Pb, As, Ba and Ni. Nickel and Cr are strongly sympathetically related and this association is independent of bedrock type.

Jan 1, 1977

By D. G. Ball

Other than being used to convey fill material for the gob stowage or building of ribside packs on advancing longwell faces, pneumatic conveying has not been used for the transport of materials on a large scale in mining operations. The technique is extensively used in the wood products industry for conveying wood chips, limestone and other ingredients for the manufacture of paper, for the transfer from railcars, barges or ships to silos or stockpiles and further transfer into the pulp mills. This method of material transfer has the distinct advantage of transporting suitable material over horizontal and vertical distances within the same system. In considering material associated with mining, this includes, ore, coal and rock up to 4 inch cubed size, throughputs of 200 tons per hour over horizontal distances of 3000 feet or vertical lifts of 2000 feet. In recent years tests have been carried out to determine the physical and economic limitations of pneumatic hoisting, the results of which have led to the installation of two fully productive coal hoisting systems at mines of the National Coal Board in Great Britain. The equipment used for the pneumatic hoisting of coal or waste rock is described in this paper, together with a brief history of the tests which led up to the installation of the two hoisting systems in Great Britain.

Jan 1, 1977

By Fred K. Stieler

The largest updraft sinter machine built has a roasting area of 132 sq.m. Sinter machines with an area of over 200 sq.m. are under consideration. These large machines require new techniques with regard to drive thrust and sealing mechanism. To optimize the results of sinter plants, the charge preparation systems and the return fines circuits were improved. Special crushers were developed for crushing return sinter of up to 800 ºC to a size of minus 6 mm. Strand cooling of Pb-sinter was investigated. Different methods for plant ventilation were compared. New processes, which might replace sintering in the future, are in the stage of large - scale testing.

Jan 1, 1977

By Charles H. Greene

This paper will describe briefly the steps taken in the development of a Central Florida phosphate ore deposit from acquisition to mining. Further, the design and early operation of the mining and beneficiation facilities will be depicted. During the 1950's, with confidence in the continually increasing requirement for phosphate fertilizer materials essential for producing food, I'. R. Grace & Cc acquired the Hookers Prairie tract containing approximately 45 million metric tons o. (50 million short ton~ of potential phosphate rock product. In 1973, at a point when the Grace captive need for rock was being greatly enlarged by a planned doubling of its Bartow phosphate chemicals plant capacity, the decision was made to expand existing phosphate rock production by building a new mine and plant. The initial annual capacity was to be 2.3 million tons (2.5 million st); however, subsequent investigation pointed to a higher than estimated dragline operating factor 'and the forecast of annual capacity was set at 2.5 million tons (2.8 million st).

Jan 1, 1977

By Peter F. Steidl

As part of the Bureau of Mines methane control program, the Upper Free-port coalbed was studied in Fayette County, Pa., where this coalbed lies about 650 feet below the Pittsburgh coalbed and contains the largest remaining reserves of any coalbed in the county. Coal and overburden isopachs, structure and joint pattern maps, and a fence diagram were prepared using data from gas and oil exploration logs and coal outcrops. These maps will aid in deter-mining the need and/or feasibility of degasifying the Upper Freeport coalbed in the study area. Much of the coalbed in this area is under 600 to 1,400 feet of overburden. By correlation with data from the Pittsburgh coalbed, the gas content at depths of this order is estimated to be between 140 to 300 cf/ ton of coal, for a total of 190 to 400 billion cubic feet of methane in this coalbed in Fayette County.

Jan 1, 1977

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

MINE VENTLATION NETWORK ANALYSIS

Jan 1, 1977

By Kenneth L. Maloney

Ten small and intermediate-sized [11 GJ/hr to 264 GJ/hr (10,000 lb/hr steam to 250,000 lb/hr steam)] coal-fired boilers in the upper Midwest have each been tested on both a bituminous eastern coal and a subbituminous western coal. The purpose of this study was to determine the feasibility of substituting western subbituminous coal for eastern bituminous coal as a means of reducing the SO x emissions from this class of boiler and to demonstrate the feasibility of greatly expanded western coal utilization as a means of reducing the use of oil and gas. The scope of this study was such that the representative boiler types were tested on both eastern and western coal for a period of time sufficient to completely characterize their individual emission and operational characteristics.

Jan 1, 1977

By Michael J. Bertoldi

The purpose of this Bureau of Mines report is to describe the methods and establish the basic economics for dragline, shovel-truck, and scraper mining systems. An overall view of the techniques of preliminary design and the cost involved is presented. Considerations of equipment selection, emphasizing short-range evaluation of required equipment, and a long-range evaluation are considered at a constant production rate over the life of a hypothetical mine. Separate cost analyses for each system were based on 1977 equipment prices, prevailing wage rates, and associated mining costs. Specific engineering and cost breakdown for such items as access roads, transmission line installation, rail spurs, etc., are beyond the scope of this report.

Jan 1, 1977

By Haydn H. Murray

Kaolin is defined and described as an industrial mineral. In addition the types of deposits -primary and secondary are defined and the genesis of kaolin from feldspars and other minerals discussed. The major deposits of the world found in the United States, Great Britain, Brazil, and Czechoslovakia are described along with many of the minor kaolin deposits. Four areas which have very large deposits of kaolin could, with technological breakthroughs to reduce viscosity significantly, become important factors in supplying the world markets which are increasing year by year.

Jan 1, 1977

By Mitchell P. Rothman

This paper concentrates on profits and other measures of return in the Canadian mining industry, especially in the non-mineral-fuels sector. The paper examines the historical patterns of mining profits, both before and after taxes, as compared with profits in other sectors of the Canadian economy, as well as some of the more important influences on mining profits. These include the prices of mineral products, provincial and federal tax policies with respect to mining , and the effect of inflation on mining profits and the financial position of mining firms - in each case, comparing mining with the other sectors of the economy. Finally, the paper provides an analysis of current and prospective rates of mining profits in relation to the capital required to ensure the future viability of the Canadian mining industry.

Jan 1, 1977

By Charles Sanford, William B. Schmidt, Eugene Moroni, John Murphy, Richard Bullock

An industry/government team sponsored by the Dept. of the Interior completed a study tour of the underground coal mining industries in Great Britain and Germany to review new and emerging coal mining technology. The group found that differences in tradition, mining conditions, and industry capabilities have led to different approaches in technological developments, many of which have the potential for application in U. S. mining. Both countries are working to improve materials and procedures for roadside pack wall. The British are developing a pump-packing system in which bentonite, water, stone, and a special cement are pipelined to the pack area to form a low strength compressible pack wall. The German industry is using anhydrite or blotzdammer to form a high strength pack wall. Both countries are using full-face tunnel-boring machines. The German industry has had considerable success with shield-type longwall supports.

Jan 1, 1977