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By Donald W. Gentry

This paper presents some of the results of a rock mechanics in¬strumentation program designed for, and implemented at, longwall panel 4N at the York Canyon Mine near Raton, New Mexico. The objective of this particular instrumentation program was to determine the response of the rock mass to longwall mining of a thick coal seam utilizing shield-type supports. Measurements were made in the rock along the ground surface, above the coal seam, in the coal seam and immediately below the coal seam. Longwall test panel 411 had a total developed length of 762 m (2500 ft) and a face width of 168 m (550 ft). The seam mining height in the panel area was approximately 3 m (10 ft). The average depth of overburden above the panel is 107 m (350 ft) al¬though it ranges from 73-134 m (240 - 440 ft). Roof support at the face was provided by Hemscheidt shields. These shield-type supports weigh 11.4 metric tons each.

Jan 1, 1977

By John A. Meech

In many multiple-sulphide ore flotation processes, it is desirable to concentrate each of the various valuable minerals into separate products. Although there are a variety of techniques and chemicals which can be employed to produce efficient separation, two basic types of flotation circuits are used: The Differential Flotation Circuit and the Bulk/Selective Flotation Circuit. Figure I depicts these two circuits in their most simplified form for the production of two concentrates and one tailing product. If three or more valuable minerals are present in an ore, a variety of combinations or extensions of these two basic flowsheets may be used. There are many examples of the successful application of both circuit types with ores containing similar minerals. Each ore must be tested individually to decide on which circuit is best. However, the following general statements can be made: 1) The differential circuit will have higher capital and operating costs than will the bulk/selective circuit due to higher rougher capacity requirement. 2) The differential circuit will achieve better separation than will the bulk/selective circuit since it is usually easier to reactivate a depressed mineral than it is to depress an already active mineral. If the deactivation problem with the bulk/selective circuit . . in can be overcome, there is a clear economic argument for its use

Jan 1, 1977

By R. H. Duthie

As at any other mine in Canada, grade control procedures are used at Steep Rock Iron Mines (1) in order to ensure that concentrator and pellet-plant operator s have a uniform feed so that they can manufacture a pellet to suit buyers' specifications and (2) to maximize ore recovery so that as little as possible finds its way to the waste dump or is downgraded by contamination. At Steep Rock, material grading 40% to 66 % Fe is considered ore. The ore may contain up to 10% sulphur. These ranges create six different stock pile types, with the possibility of more if large concentrations of arsenic are encountered. Although grading and mining techniques used to accomplish these ends are fairly standard, there is an appreciation and willingness by hourly and staff pit personnel to make grade control effective. This produces vertical and horizontal communication, which is necessary for success in this field. At Steep Rock, the waste-to-ore ratio is greater than at any other iron ore mine in Canada. Also, a high percentage of the ore mined is direct pellet feed. For these reasons, .grade control is very important.

Jan 1, 1977

By Pedro Lilienfeld

This report describes a program to develop, design, fabricate and subject to environmental testing three prototype collection-sensing devices of an eventual mining-machine mounted automated monitor for the measurement of the respirable fraction of coal mine dust to determine both short-term as well as average mass concentrations over typical 8-hour shifts. The design of this instrument is based on collection by filtration and mass sensing by beta-radiation attenuation. The emphasis of this development program was to evolve a rugged, stable and reliable collection-detection head compatible with the environment to which An eventual monitor will be subjected. Laboratory testing of this prototype instrument was performed over a representative range of temperature, humidity, dust concentration and composition, shock and vibration. The results of this testing program indicated that the operation of the prototype version His compatible with these environmental conditions and that further development of this configuration into a field operational device is justified.

Jan 1, 1977

By Edward S. Hsia

Pluor Utah has been closely associated with the engineering and construction of earth bottom thickeners for porphyry copper operations, for the counter-current decantation circuit of a gold cyanide plant and similar applications in mineral processing. During the past 13 years, some 18 of these thickeners have entered service and the bottoms have proved to be watertight structures with no particular problems encountered. In the course of this work, technological advances have been realized in the procedures for engineering and construction of these units to assure watertight basins and achieve all possible economies in construction. This paper describes the successful application of engineering and construction techniques for a number of these thickeners.

Jan 1, 1977

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is intended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

By Ann G. Kim

The Bureau of Mines estimated the methane content of a coal, which depends primarily upon rank and pressure, from the adsorption equation V kpn, where k and n are constants related to rank. By incorporating corrections for moisture, ash, and temperature, and estimating pressure and temperature as a function of depth, the methane content of coal in place can be estimated from the following equation: [ ] Values calculated with this equation generally are in reasonable agreement with direct determinations. By assuming a standard moisture and ash content, and using the hydrostatic head to estimate pressure, a graph of rank and depth versus gas content was constructed. Although estimated values were consistently high for several high-volatile bituminous coals from an area where the pressure is known to be less than hydrostatic, the estimated methane content for most coals shows reasonable agreement with values determined by the direct method.

Jan 1, 1977

Minerals are a fundamental component of the Nation" material and economic base. Without a continuous supply of minerals to meet growing and changing needs, the basic character of our society would be very different. The importance of minerals to the United States was reemphasized by the Congress in I970 when it enacted the Mining and Minerals Policy Act, which stated that it is the continuing policy of the Federal Government in the national interest to foster and encourage private enterprise in (I) the development of economically sound and stable domestic mining, minerals, metal and mineral reclamation industries, (2) the orderly and economic development of domestic mineral resources, reserves, and reclamation of metals and minerals to help assure satisfaction of industrial, security and environmental needs, (3) mining, mineral, and metallurgical research, including the use and recycling of scrap to promote the wise and efficient use of our natural and reclaimable mineral recources, and (4) the study and development of methods for the disposal, control, and reclamation of mineral waste products, and the reclamation of mined land, so as to lessen any adverse impact of mineral extraction and processing upon the physical environment that may result from mining or mineral activities.,.

Jan 1, 1977

By Michael Rieber

An analysis of coal slurry pipelines was presented in our May 1976 study, Route Specific Cost Comparisons: Unit Trains, Coal Slurry Pipelines and Extra High Voltage Transmission (4]. The present study extends that analysis. The earlier work included technical and economic cost descriptions of the black Mesa and ETSI pipelines as well as some hypothetical pipeline routes. Water problems, safety and environment, required resources, and labor impacts were discussed at some length. Additionally, pipeline impacts on competing railroads, slurry-rail comparisons, and cost escalation. were analyzed. The difference in pipeline profitability to an owner-operator versus a promoter-builder was suggested. These aspects are not redone in this study. Here, we present a synopsis of the previous results and a general statement of coal slurry pipelines. Extensions of the arguments are presented where they appear warranted. New material is developed in the area of pipeline branching and tapping. This would appear necessary if slurry pipelines are to function as more than private lines; if they are, for example, to be responsive to common carrier requirements.

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. Its estimated recoverable reserves in Fayette County are between 670 and 800 million tons. 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 determining 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.

Jan 1, 1977

By D. W. Hayley

The rapid expansion of exploration drilling with anticipated production facilities for oil and gas in the Mackenzie Delta region of the Northwest Territories has created a demand for granular construction materials. This paper discusses the technique adopted and experience gained by the authors from several major resource evaluation programs in this remote area. The first part of the paper describes a methodology for deposit identification, logistics of helicopter and ground-based drilling operations and the sampling difficulties which are unique to permafrost: soils. The second part describes the exploitation of a large glaciofluvial deposit at YaYa Lake on Richards Island. Granular construction material is sparse in the delta region relative to projected demand. Exploitable sources of granular materials for aggregates or construction borrow are found in glaciofluvial deposits of Pleistocene age or in outcrops of Paleozoic bedrock. Glaciofluvial landforms can be located by reference to published surficial geology maps coupled with airphoto interpretation. Preliminary assessment of these features in a large region is most economically carried out during the summer months with a drill that is transportable by helicopter. Once prospective borrow pit sites are identified, a detailed ground-based winter drilling program must be undertaken to establish aggregate quality and quantity, and to provide information on natural features which could affect development. The glaciofluvial terrain has been highly modified by the formation of massive ground ice within the gravel deposits. This presents some unique pit development problems which are not encountered in a normal bedrock quarry operation.

Jan 1, 1977

By Clarence O. Babcock

This Bureau of Mines publication presents guidelines for mining near surface and underground bodies of water. The guidelines were based on information developed under contract in three phases of study, as follows: (1) Collection and documentation of data from worldwide sources; (2) application of existing guidelines, foreign, Federal, and State, to case histories of previous inundations; and (3) development of recommended guidelines for underground coal mining near bodies of water aimed at maximum efficient utilization of underground coal resources consistent with minimizing inundation hazards. While the contract guidelines were for the mining of coal seams, they may also be used for mining any tabular sedimentary mineral deposit. Tables are given for the determination of the size of coal pillars needed; for other bedded deposits, similar tables could be determined based on their strength properties.

Jan 1, 1977

By Michael P. Hardy

The report described improvements and applications of the Hybrid Computer facility. Improvements implemented under U.S.B.M. Contract H0252035 included expansion of the capability to model nonlinear seam behavior, installation of a color video output display monitor, and further development of software capabilities. To demonstrate the capability of the system, firstly, the influence of nonlinear seam behavior response to the occurrence of coal mine bumps was fully investigated and secondly, the effect of improper mining sequence on bump occurrence was demonstrated. In addition, the system was applied to the analysis of a series of practical coal mine problems. Mines in three coal seams were analysed to investigate the parameters which contribute to the occurrence of coal mine bumps.

Jan 1, 1977

By Robert G. Woolery

Union Carbide_ began looking seriously at heap leaching in 1971. At that time some 1.6 million tons of mineral averaging 0.040% U308 were stockpiled at various sites around the Gas Hills, Wyoming, uranium facility. Several alternatives for economically exploiting these reserves were considered and heap leaching seemed the most attractive. At the time, Western Nuclear Inc. was operating a heap leach project nearby in which the low-grade ore was leached with sulfuric acid, the product liquor treated in an on-site solvent extraction circuit, and the stripped product liquor re-acidified and recycled. They were most generous in allowing us to visit their site, answering our questions, and were helpful in discussing the problems associated with heap leaching. They confirmed our belief that, it was possible to operate a heap leach profitably on material too low grade for. conventional milling. Based largely on what we had learned from Western Nuclear's experience, a program was set up involving a laboratory study to determine the characteristics of the mineral stockpiles as related to heap leaching and to conduct a pilot heap leach adjoining our Gas Hills mill. Basically, the pilot heap construction and leach procedure were similar to those described in the literature(1,2) with certain modifications to permit detailed monitoring of the operation. In May, '1972, the decision was made to construct a test heap. The UCC plant at Gas Hills, Wyoming was selected as the most appropriate site for the follow¬ing reasons:

Jan 1, 1977

By K. C. Ko

The pit slope angle dictates the economics as much as the depth of the pit. Steeper slope provides more ore reserves, at the same time, the steeper slope presents higher probability of instability and associated maintenance problems. While large open pit mines mostly belonged to nonferrous metals in the past, other mines are becoming deeper as the mine economics permits deeper mine operations, Such minerals include coal, uranium, phosphate, and others. There are some basic differences between an open pit slope and slopes that are encountered in usual civil engineering work such as dam embankments and highway cuts (Figure 1). The stability of the civil engineering slope changes continuously with time due to ground-water movements, weathering, etc. But the stability of the open pit slope (Figure 2) changes more drastically day-to-day or even hour-to-hour, These changes occur because not only is the slope geometry being continuously changed by the mining operation, but also different geology and geologic structures are being exposed on the slope. Even when a particular slope area is not presently being mined, excavation in adjacent areas can affect the general condition of that slope area. A pit will experience some slope failures during its life.

Jan 1, 1977

By Matthew I. G, Hall P. G

The Selective Precipitation (Basics) Process is a means of controlling impurities such as the ions of Mn, Mg, and Cl as well as sulphate and water, in an electrolytic zinc plant circuit. This is achieved by precipita- ting zinc selectively as a basic zinc sulphate from a portion of impure circuit solution. The impurities remain in the solution, which can be discarded, while the zinc, substantially free of impurities, is returned to the main circuit by using the precipitate as a neutral- ising reagent. A description of the process and its development to a full scale operating plant at the Risdon Works of the Electrolytic Zinc Company of Australasia Limited is Presented.

Jan 1, 1977

By H. C. Harrell

The Tennessee Valley Authority began employing geophysical well logging for foundation investigations in October 1973. Since that time more than 3,000 holes have been evaluated for engineering purposes. The Tennessee Valley Authority has not actively used geo-physical well logging for exploration of construction materials, but we feel that much of the information derived from geophysical logs for foundation exploration is applicable to the construction materials industry. This paper will then discuss geophysical logging as applied to foundation engineering and, by implication, the feasibility of use in construction materials exploration. The use of geophysical logging and percussion drilling instead of coring has greatly expanded TVA's data acquisition capabilities and has also resulted in substantial savings in time and money. Economical boreholes are obtained through the use of large percussion track drills (Figure 1). This equipment is capable of drilling through the overburden, setting steel casing on the top of rock, and drilling the rock beneath the casing. Holes as deep as 400 feet (121.9 m) have been drilled by this method.

Jan 1, 1977

By W. W. Cummings

Canada's only current tungsten producer started up in 1962 with a small open-pit mine on the Flat River , 180 air miles north of Watson Lake, Yukon Territory. The orebody was in a contact-metamorphic skarn zone and contained about 1.5 million tons of ore grading an estimated 2.47% W03 and 0.5% copper. Near the end of the open pit , a new zone was discovered on the lower limb of the same structure, and the decision to go underground was made in 1972. The new "E Zone" contains over 4 million tons of ore grading an estimated 1.6% W03 and 0.28% Cu , and has been supplying the concentrator at about 175,0 00 tons/ year since late 1974. A continuing program of change and up-grading is necessary in the conversion from a seasonal open-pit mine with limited life to an underground operation with twenty years of reserves. Changes are necessary in plant and services as well as the mine. Also, environmental protection requirements have changed from rudimentary to rigorous over the life of the operation. This paper sums up the changes in the operation since 1971 and outlines the changes yet to come.

Jan 1, 1977

By A. A. McDonald

Anode casting has been in operation for two years in Hudson Bay Mining and Smelting's Flin Flon smelter. The new plant allows all casting to be done on one shift and so achieves considerable labour savings. The equipment and operations are described. Some important features are as follows: very consistent anode weights by the use of the load-cell controlled casting ladle; excellent mould life ; very low reject rate; and trouble-free take -off tower. Some of the start-up problems are described and an outline is given of the main operator functions. Data on labour, propane and maintenance costs are presented.

Jan 1, 1977

By Louis M. Perlman

CAN PRESENT TRENDS CONTINUE? Can population growth in the world keep going at the average rates of the last few decades, till, say, the year 2000? And beyond? At the same time, can we expect steady increases in mineral consumption per head, all over the world, as the living standards of many nations converge toward the living standards of North America? If they do converge? Does the total fund of world resources extend, with foreseeable techniques, to supplying the consequent demands for metals, non-metallic minerals and energy? Do we have the requisite economic and scientific techniques available to answer these questions? Certainly, we cannot forecast over decades with any certainty. There are many, of course, who seem to believe that by the simple fitting of trends, they can tell us something about the world and resource constraints in the year 2000, twenty-three years from now. It is significant that many studies of this sort have added sustenance to the 'doom-watching' fraternity of commentators. The reason is simple. The extrapolation of exponential trends into the distant future frequently leads to the most astounding and impossible scenarios. Another feature of exponential growth is the suddenness with which certain fixed limits are approached. It took world population two hundreds years to increase by 1/2 a billion, from 1650 to 1850. Yet some U.N. estimates suggest that the net addition to human population will be over 2 billion between now and the end of the century. Thus, the present world population would increase from a little under four thousand million today to rather over six thousand million in the year 2000.

Jan 1, 1977