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By J. P. Baur

The sensitivity of radiochemical techniques makes possible the study of the initial-stage sulfuric acid leaching kinetics of chalcopyrite and other copper sulfide minerals. This Bureau of Mines study of the initial leaching of chalcopyrite used techniques to evaluate the molecular and electrochemical processes. High-grade Transvaal chalcopyrite was neutron-irradiated in a TRIGA reactor4 to produce radioisotopes copper-64, iron-59, and sulfur-35. Dissolution rates were measured in the time interval zero to 60 minutes, during which time significant anomalies were observed. First was an initial period of rapid dissolution lasting a few minutes; second, an arrest or ?plateau? region usually lasting from 6 to 10 minutes; third, a second period of dissolution of lesser rate than the first. The effects of solution variables such as pH, oxygen partial pressure, and ferric ion concentration at different temperatures were measured.

Jan 1, 1974

By J. E. Murphy

A method is being developed by the Federal Bureau of Mines for recovering lead metal from galena without the generation of SO2. Lead chloride is obtained by leaching lead concentrate at a temperature of approximately 100° C with FeCl3 solution: PbS + 2FeCl. " PbC1 2 + 2FeC1 2 + S. Electrolysis of the PbCI 2 product in a fused-salt bath results in deposition of molten lead metal at the cathode and evolution of chlorine at the anode. The chlorine can then be absorbed in the spent leach solution to regenerate FeCl3 for recycling. Optimum electrolyte composition was a PbC12-LiCl eutectic containing 7.6 wt-pct LiCl. The PbCl2-NaCl eutectic also proved satisfactory. Electrolysis in the PbCl2-LiCl bath at 450° C yielded 99 pct current efficiency at a current density of 5 amp/in2 with an energy requirement of only 0.24 kW-hr/lb metal produced. This compares with 98 pct current effi¬ciency and 0.26 kW-hr/lb metal produced for the PbCI2-NaCI bath. A typical lead deposit contained less than 100 ppm total detectable metallic impurities. At the low temperature employed for electrolysis, there was essentially no vaporization of Pb or FbC12.

Jan 1, 1974

By James R. McVey

A new method for measuring deformations of rock surfaces in underground excavations has been suggested by Dr. James Powell of Brookhaven National Laboratories (BNL) and subsequently developed and successfully demonstrated in a mining environment by the Federal Bureau of Mines, Spokane Mining Research Center (SMRC) and Brookhaven National Laboratories. The system uses 35-mm photography of targets strategically located on surfaces of interest, such as across the roof and on the sides of a mine drift or tunnel. The optimum tar-get, as determined in this investigation, consists of a white ?X? made with 1/8-inch-wide reflective tape on a black 6-inch square. Photographs, taken in pairs from two separated camera positions and at regular time intervals, were analyzed at the Bureau by hand and at Brookhaven National Laboratories using techniques and equipment similar to those used in cloud chamber film analysis. Test results show that deformation-measurement accuracies of better than ±0.020 inch in a drift that is 20 feet wide can be expected. This degree of accuracy, plus providing displacement data in the X, Y, and Z directions (rather than the one direction formerly possible), makes this a noteworthy and useful tool for industry as well as for mining research.

Jan 1, 1974

By R. T. McLamore

Lack of sufficient native permeability or skin damage caused while drilling wells for in situ leach mining projects may necessitate stimulating injection and production we1ls to increase the leaching rate to economic levels. Such stimulation processes could include acidization, hydraulic fracturing, or explosive fracturing. This paper describes an explosive fracturing process that is being developed primarily to stimulate the production of oil and gas wells, but may be useful in in situ leach mining projects as well. The process utilizes a liquid explosive that has unique safety features. The chemicals that form the explosive are subdivided into two pumpable, non- detonable components. Technology has been developed to pump these two components independently but simultaneously into the well and blend them together downhole to form the explosive. As such, surface facilities and personnel are not exposed to explosive hazards. The explosive formulations utilized in the process have been subjected to numerous safety and characterization tests and been qualified for use in deep wells with temperatures and pressures up to 250°F and 10,000 psi. The explosive composition can be varied to produce an explosive ranging, energetically, from a blasting agent to a high explosive that can be detonated after injection into a borehole, a porous media or into thin naturally occurring fractures within the roc

Jan 1, 1974

By Leland L. Mink, Roy E. Williams, C. Daniel Kealy

The passage by Congress of Public Law 92-500 (the 1972 Water Pollution Control Act amendment) has placed a new emphasis on the need for methods to minimize the escape of water from tailings ponds. Presumably tailings pond seepage will fall under the jurisdiction of the act. This paper is designed to explain some of the problems caused by leakage from tailings ponds and to present a method by which leakage can be minimized if not eliminated. Ground-water pollution in one case studied by the authors results from leaching of old jig tailings that are intermixed with the upper part of a sand and gravel aquifer. Anomalous concentrations of zinc, lead, and cadmium occur in ground water and soil samples taken from the portion of the sand and gravel aquifer containing the old jig tailings. Analysis of water samples from a tailings pond located in the area indicates that the pond water is not the source of the heavy metal concentrations found in the down-gradient ground water. However, leakage from the pond and water from the pond's decant system combine with natural ground water to compound the problem by raising the water table into old jig tailings which cover the upper portion of the aquifer. The ground water which discharges from this aquifer causes a statistically significant decrease in the quality of the receiving stream water. The shallow ground water contains oxygen; therefore, corrective measures include lowering the water table to depths below the old jig tailings which cover the aquifer at ground level. This, in turn, implies elimination of ground-water recharge by subsurface leakage from the pond. A laboratory study and a mathematical model study have revealed that seepage from such ponds can be minimized by a carefully designed and managed peripheral tailings discharge system. The process involves maintaining the slime zone and the free-water surface near the center of the pond so that the slimes retard downward and semilateral movement of pond water. The free-water surface must not be allowed to extend out over the nonslime portion of the tailings during or after pond operation. Mathematical model output reveals that this method can hold the subsurface discharge rate to as little as 110 gpd per acre of pond water area. The technique should be applicable to any tailings pond system in which the loss via seepage of poor quality water must be minimized or where recharge of ground water by losses from a tailings pond must be minimized, regardless of the reason.

Jan 1, 1974

By Terry O. Arney

Ore Reserve Models are well established evaluation and mine planning tools. BY definition, these models are made up of regularly sized blocks, arranged in a three dimensional matrix. Two dimensions correspond to north and east directions, and the third, to the depth or elevation. The dimensions of the blocks need not be equal, but generally at least two of the dimensions are equal. The blocks are located in space by coordinates which are generally translated into index values for computer applications. Each block will have quantitative attributes, such as grades, densities, rock characteristics, etc. assigned to it. The process of assigning values to each block in the three dimensional matrix is the process of ore reserve model development. One of several interpolation procedures may be employed to predict the value of a block, based on surrounding data. Block value models have several uses. The utilization of block models in ore reserve computations is quite common. Here, ore reserves may be calculated by level or by cross-section for the entire deposit. For each ore reserve calculation, multiple cut-off grades may be analyzed to determine the ore reserves under different cut-off conditions. The other major use of block value models is in mine simulation. Through simulation, profitable studies that analyze the effect of alternate ore removal sequences can be undertaken to determine economic optimality. Other studies that are undertaken in mine simulation problems include the evaluation of mine layout, pit slope effects, and the impact of varying cut-off grades.

Jan 1, 1974

By Ham G. I, Just G. D

The model considers a range of design parameters and operating condit- ions and evaluates the significance of these in the ultimate design of a mine. It also considers organizational features associated with the mining method and examines the inter-dependence between operations. An important characteristic of the model is the use of both stochastic and deterministic methods to study the behaviour of the complete mining system. The simulator selects the appropriate unit operation, computes and records its time, performs it and then calculates the production and cost data. Output is in the form of shift, day, week or period repor-ts. These reports will indicate problem areas such as restrictions in the production network for a given set of conditions. The likely effects of alternative means of solving these problems can be evaluated by changing the original input. Such information could be used by the mine management to select an

Jan 1, 1974

By William C. Larson

A study was conducted by the Bureau of Mines to provide quarry operators with information regarding (1) the effects of jointing and bedding on rock fragmentation when bench blasting in two small-scale (2.5-ft) limestone benches, and (2) the successful use of inexpensive equipment and field techniques to determine the orientation and spacing of joints and bedding separations within the quarry. Using inexpensive equipment, such as a pocket transit and steel and paper tapes, joint and bedding separations were mapped and their frequencies measured. Results from two small-scale bench blasts in the Stewartville member of the Galena limestone formation showed that when the row of vertical blast-holes was oblique to the vertical joint orientations, the backface expression was outlined by two relatively large triangular protrusions (joint surfaces). In this blast, part of the rock burden was unbroken. When the line of vertical blastholes paralleled a predominant joint set, all of the rock burden was broken and displaced. The thickness of fragments that had been displaced by a blast correlated with the observed bedding thickness in the bench.

Jan 1, 1974

This report is a compilation of all information obtained in accordance with the requirements of contracts S0122076 and H0232056. A series of eight coal mines were visited to determine their communications usage and requirements. Presently available equipment was surveyed and evaluated to determine its applicability to the needs of the mines. The equipment studied includes that made by the following companies: Anaconda Telecommunications Division Andrew Antenna Bendix Communications Division Collins Radio Group of Rockwell International Executone Communication and Sound Systems Gai-tronics Mine Safety Appliances Company Motorola Communications and Electronics, Inc National Mine Service Company Plessey Communications Systems Corp Pye Electronics Limited Reach Electronics Set Com Corporation Sonex Incorporated

Jan 1, 1974

By T. V. Falkie

REMARKS OF DR. THOMAS V. FALKIE, DIRECTOR, BUREAU OF MINES, U.S. DEPARTMENT OF THE INTERIOR, BEFORE THE FALL MEETING OF THE SOCIETY OF MINING ENGINEERS, AIME, ACAPULCO, MEXICO, SEPTEMBER 23, 1974 This is a time of uncertainty on the world mineral scene. For some of the world's so-called "developed" countries, reserves and production of key minerals are running low. And, we have learned that the energy so essential in recovering and processing minerals can suddenly be in short supply. The prospects for a "no growth" situation in energy or mineral consumption are practically nil. Moreover, the world's economy is in flux, casting doubt on whether traditional mineral customers will continue to be able to buy, or for that matter, whether traditional suppliers of minerals will continue to sell. It is clear that the mineral situation is contributing to world inflationary pressures, which incidentally are most damaging to developing countries. So it is appropriate that SME members devote this session to the world mineral situation, and consider some of the opportunities and responsibilities that we will inevitably encounter as the future becomes the present. The opportunities, to me at least, are especially intriguing, I have the good fortune to be part of an organization that has an enormous capability and responsibility for dealing with mineral problems. The Interior Department's Bureaus, including the Bureau of Mines, have been around for a long time. They are. a prolific and reliable source of both mineral information and mineral technology.

Jan 1, 1974

This report summarizes the results of several field tests conducted by Collins for the Bureau of Mines under contract S0122076 and contract H0232056. The field projects represent a part of Collins continuing effort on a broad study of coal mine communications. These experiments analyze the propagation characteristics of radio signals in a working coal mine environment. The intent of the program is to provide basic propagation loss characteristics by which we may evaluate various approaches to an integrated mine communications system. The goal of such a system is to satisfy both operational and emergency communications needs in the mine.

Jan 1, 1974

By L. S. Darken, H. A. Wriedt

The equilibria at 1 atm total pressure and 600° to 1300°C (1112° to 2372°F) between gas mixtures with various partial pressures of the reactive constituents (principally sulfur dioxide, carbon dioxide, water vapor, oxygen or carbon monoxide, and hydrogen) and coexisting solid phases (groups variously including calcium oxide, calcium carbonate, calcium sulfide, calcium sulfate, iron, ferrous sulfide, and the iron oxides) are examined. Tables and charts show the combinations of temperature, oxygen activity, and carbon dioxide partial pressure under which the various groups of the solid phases coexist and the corresponding sulfur dioxide pressures. In the presence of calcium sulfide, calcium sulfate, and calcium oxide, the partial pressure of sulfur dioxide has a peak value at each temperature which increases from 101 atm at about 800°C (1472°F) to 1 atm at about 1200°C (2192°F). With water vapor present, hydrogen sulfide may predominate among gaseous sulfur compounds, particularly at low temperatures and oxygen activities; under all other circumstances considered, sulfur dioxide is the dominant gaseous sulfur-bearing species.

Jan 1, 1974

By T. A. Griffin

Gentlemen: The subject of this paper is: ADVANCED APPLICATIONS OF BUCKET WHEEL EXCAVATORS AND RECLAIMERS. Against an urgent world wide energy crisis, the role of bucket wheel excavators and reclaimers in the surface mining of fossil fuels and other ores has been raised to new prominence. This paper will review the reasons for the expanded application of bucket wheel technology, its unique contributions, and other factors relative to volume, cost, versatility, and efficiency. Today, surface mining is faced with the twin challenge of (1), accelerating the rate of removal of massive quantities of overburden and ore, and (2), replacing comparable high volumes of overburden back into the mined-out portion of the pit. Optimum quantitites for - a single electrical power plant now range from 5 to 15 million tons of coal per year. The use of bucket wheels offers the best method for meeting this challenge at lowest possible cost. For example, an advanced application that also satisfies environmental concerns involves the simultaneous functioning of two bucket wheel excavators during surface mining operations. Working at spaced intervals and different levels in conjunction with a transfer conveyor and stacker, one excavator removes the ore while the other one transfers overburden to a stacker that replaces it back into the open pit. The result of this continuously operating cycle is: (1) removal of ore and replacement of overburden back into the pit in massive quantities, (2) at accelerated volume and extreme low cost that cannot be matched by conventional loading machines of any size, and (3) fulfills a basic environmental requirement which is to

Jan 1, 1974

By Jerry M. Whiting

Greater awareness of the increasing need to develop supplementary energy sources is accelerating us towards many basic decisions regarding future utilization of mined energy materials -- uranium, coal, oil sands and oil shale. The latter material comprises a major potential source of oil which will require creation of unusually large and low-cost underground mining systems. In this paper, the author briefly outlines and analyzes several of the factors which continue to provide the somewhat unique character of oil shale nine planning and mine operation.

Jan 1, 1974

The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the ?fire door? type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self -Propelled Electric Face Equipment/Automatic Emergency Brake s II by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By K. A. Natarajan, I. Iwasaki

The meaning and the utility of redox potential (Eh) measurements in sulfide flotation systems are examined. Since some preliminary plant Eh and laboratory flotation data were available, experiments were made to establish the pH range at which a platinum electrode might be used for such measurements without much difficulty in aerated systems. Triangular wave voltammetry was used to study the surface conditions of the electrode immersed in pyrrhotite suspensions at different pH. The measured Eh both at the plant and the laboratory is interpreted in terms of the experimental water-oxygen line.

Jan 1, 1974

By C. E. Schmidt

Condensate waters from the Bureau of Mines Synthane process for coal gasification have been investigated by mass spectrometric methods to determine the organic contaminants. Waters from the gasification of six coals were extracted with methylene chloride, yielding 0.6 to 2.4 weight-percent extractable material. Using high-resolution mass spectrometry (HRMS), combined gas chromatography-mass spectrometry (GC-MS), and low-voltage mass spectrometry, 60 to 80 percent of the extract was found to be phenolic. About 20 organic contaminants have been identified and are present in the condensate waters from each coal gasified. The relative distribution of contaminants in the condensate water was nearly the same for the six coals gasified under various conditions; phenolic compounds were the most abundant in all cases.

Jan 1, 1974

By Frank C. Appleyard

As the environmental movement gained force during the past few years, it was inevitable that attention would be focused on surface mining, and we have seen this method of extracting minerals from the ground come under heavy attack by conservation groups, the press and television, legislators at all levels of government,, and the public at large. It is difficult, and in some situations, perhaps impossible, to measure either the need for, or the results of, land reclamation in absolute terms. Therefore, much of the criticism of surface mining has been based upon subjective analysis rather than hard data, with the result that discussion of the subject often includes a fair amount of emotional response. To be fair, this reaction is not limited to just our critics; even we hard headed engineers sometimes respond in the same way, an observation with which you may agree when I finish this talk. This leads to the thought that whether you are for it, or against it, land reclamation in many respects is a state of mind. That is, our reaction to it can vary considerably, depending on how far we have thought it through. And think it through we must, because the pressures being brought to bear need to be met with positive actions if the problem is to be brought under control, and in the next few minutes I would like to discuss from a management point of view some ideas which might aid in this thinking process. It would be a mistake, I believe, to think that the current energy crisis will suddenly bring the environmental movement to a stop, and therefore, we can relax and go back to running our busi¬ness the way we used to. This is not realistic; on the contrary the energy crisis is focusing attention on the limitations of our natural resources as nothing else could, and with respect to land

Jan 1, 1974

By D. E. Hirsch

The Bureau of Mines, as a part of American Petroleum Institute Research Project 60, Characterization of the Heavy Ends of Petroleum, has made extensive use of gel permeation chromatography (GPC). Data developed in this study were used to develop several correlations that greatly expanded the usefulness of GPC and the data have been used as an aid in the interpretation of mass spectra (MS). GPC retention volume data on pure compounds were used with molecular structure to develop correlations that can be used to accurately predict retention volumes, molecular volumes, densities, chain lengths, and ring numbers of many components of petroleum without resorting to further laboratory experimentation. Conversely, the correlation can be used to select or reject some compounds from several possible compounds that are indicated on the basis of MS analysis. The utility of these correlations in compound type characterization is demonstrated by showing their application to 330° to 550° C fractions from a low-sulfur and a high-sulfur crude oil.

Jan 1, 1974

By Mohamed Yusuff

Modern transportation systems are one of the most important achievements of our civilization and provide us with tools for broadening individual and social freedom of choice. The transportation system initiated today is handed dawn to the next generation, probably with little choice because of the enormous expenditure of monies involved, and influence their way of life as to where they should live and where they should work. The ever increasing antagonism between the citizens and the planners of the transportation systems necessitates a careful review of the entire planning process. The planning process can be broadly classified into: the goal formulation and decision making process; the plan development process; and the plan implementation process. THE GOAL FORMULATION AND DECISION MAKING PROCESS Goal formulation and decision making is one of the vital phases of the planning process and is primarily based upon social values. In measuring social values, the planner must employ an appropriate scale of measurement since in the absence of this yardstick, these values tend to became vague and abstract ideals. The need for major social programs and concerns (poverty, etc.) of the urban areas should be analyzed to determine the type of transportation system which would contribute to the solution.

Jan 1, 1974