Search Documents

By Robert E. Ennis

The somewhat misnomered "continuous" face section is in most mines today still far from perfect continuity. Achieving uninterrupted flow of coal from the mining machine to the outside has been a long sought for goal. Clearly, the largest problem to be solved in continuous mining today is one of increasing the cutting time of the miner. Full machine utilization can never be achieved with the new high capacity miners, as long as their performance is tied to that of the shuttle car. Figure No. I illustrates the point at which shuttle car haulage distance determines unit productivity rather than the productive capacity of the miner. Continuous mining is never realized. A recent development has proven, however, that truly continuous mining and haulage is possible. The Bell & Zoller Coal Company working with the Research and Development Department of Hewitt-Robins Inc. developed and perfected a new mining system which offers advantages in terms of increased productivity at reduced mining costs and enhances the safety of personnel at the face. This new system involves the use of two pieces of equipment that form a unbroken link, at all times, between the mining machine and the mine belt haulage system. These pieces are a Mobile Bridge Conveyor, and an extensible panel conveyor. The following areas of discussion will be covered during the review of this development. I. The design and operating features of the new system. 2. Its application in underground mining 3. The performance of the system to date 4. Operation and maintenance cost considerations 5. Safety features of the system

Jan 1, 1965

By A. E. Raddatz

The U.S. Department of the Interior, Bureau of Mines, is investigating methods for recovering tungsten from domestic resources. A calcine-quench-leach (CQL) technique was developed for the extraction of tungsten from the Golconda, Nevada, hot springs ores. The deposit contains disseminated tungsten, which cannot be beneficiated by conventional techniques and must be treated by hydrometallurgical methods. The CQL procedure consists of calcining the ore at 900° C for 3 hr, quenching in a solution containing 1.5 parts of NazCO3 and 1.5 parts of NaOH per part of WO3 in the ore and at a solution- to-ore ratio of 3 to 1, leaching at 200° C and at 250 psig for 3 hr, and filtering and washing the residue. A series of closed-circuit batch tests showed that 92 pct of the tungsten was extracted from a sample containing 2.32 pct WO3. The pregnant solution contained 11 q of W03/1.

Jan 1, 1982

By Rodolfo V. de la Cruz

Abstract. The Hoskold mineral valuation method was critically examined. The original derivation was presented and found to contain a number cf erroneous assumptions as follows: the sinking fund must be available for reinvestment in another property; the series of reinvestment of the sinking fund results in a perpetual annuity to the investor, and; evaluation of the present value of the net cash flows at the speculative rate of interest. The proper procedure of deriving the Hoskhold mineral valuation formula was discussed and illustrated with a cumulative cash position diagram, a useful tool in economic evaluation and investment decision methods.

Jan 1, 1980

By James Thompson

Mine planning at Consolidation Coal Company's (Consol) Glenharold Mine in North Dakota is being constrained by environ¬mental concerns that did not exist when the mine opened in 1965. One such concern which developed in the mid-1970's is the impact of mining on woodlands that are considered impor¬tant wildlife habitat. To better coordinate mine planning with permitting, a cooperative task force was created to evaluate woodlands for their wild¬life habitat potential. The task force included representatives from Consol and state and federal agencies. This cooperative process is seen as a method of communication between industry and government and as a way of developing decision-making tools for mine planners and regulatory agencies.

Jan 1, 1981

By S. A. Bortz

IIT Research Institute has initiated several multi-sponsored research programs. In this paper the methods for developing four of these programs are discussed. In general, a broad area of investigation must be proposed to interest a spectrum of different industries. The work must not touch upon proprietary data and will probably involve a number of scientific disciplines. Thus, the problem to be solved will attract sponsors who need to know more about the area under study but do not wish, as a single company, to commit the resources required to obtain the necessary know-how for their needs. The paper draws on the background of four IITRI multi-sponsored projects: Size Reduction, a study of grinding of material to reduce their particle size; Melt-Formed Ceramics Research, a method of producing dense, polycrystalline ceramics using glass forming methods; Binders in Ceramic Processing, which addresses the problems associated with the use of organic aids for ceramic processing; and a Study in Air Pollution Technology, a program to review and assess pollution control equipment for current and future applications.

Jan 1, 1984

By D. J. Frey

While costs of most commodities and services have increased markedly over the past 25 years, the cost of electricity has steadily declined. One of the reasons for this price decline is the improved efficiencies of generating plants which is shown in Fig. 1. 1,2 Another reason for this is the decline in coal production costs. Efficiencies for the best plant increased from about 32 percent in 1540 to about 40 percent in 1962 and then decreased slightly to 38 percent in 1965. The increase in efficiency for all plants (US average) has been even more notable, progressing from less than 15 percent in 1940 to about 32 percent in 1965. The chief reason for the improved efficiency is the change in operating steam temperatures. These increased about 12 F per year until 1200 F was reached in 1962. At this high temperature excessive corrosion of super-heater and reheater tubes was experienced and steam temperatures were dropped back to 1050 F and even 1000 F in some cases. To successfully compete against other energy sources for generating electricity, this corrosion problem must be solved so that operation at higher temperatures and thus, increased efficiencies will be possible.

Jan 1, 1967

By Michel Gauthier

Several zinc showings, exhibiting many similarities to the well-known Balmat-Edwards zinc deposits of New York State, occur within the Grenville Supergroup strata of the Mont-Laurier Basin, Quebec. Metallogenic mapping programs have revealed much of the stratigraphic control of this mineralization. This control is observed on both regional and local scales. At the regional scale, these showings are confined to the perimeter of the Mt.-Laurier Basin, while at the local scale, a definite association between the zinc mineralization and dolomitic marble horizons is clearly exhibited from detailed mapping. These new exploration guidelines have proven to be useful for base-metal exploration in the Mt.-Laurier Basin and should be applicable to the entire Grenville Province.

Jan 1, 1983

By D. Suarez

The work of engineers responsible for the design and performance of mine facilities is often challenged by economic and practical constraints in the field. Problems have developed in implementing design criteria dictated by persons or agencies not familiar with the dynamic nature of mine engineering. Regional and site-specific conditions frequently require changes to standard designs, or the use of a completely innovative approach, which is not provided for in the regulations. The implementation of engineering design, therefore, usually requires a hard-sell approach to management and regulatory agencies that allows for a happy-medium to all parties concerned. Flexibility on the part of the regulatory agencies is needed to solve operational and environmental problems with sound engineering. Typical hydrologic issues which will be discussed fall in the following general categories: ? Design criteria for sizing water control structures (i.e., culverts, diversion and sedimentation ponds, ditches, etc.) ? Implementation (construction and operation) difficulties ? Regulatory compliance ? Reclamation planning with hydrologic considerations ? Protection of groundwater resources

Jan 1, 1986

By Hubert Erik Sherer

Determination of the best time to replace an aging unit of equipment is a recurring problem which is common to essentially all surface and underground mining operations. Virtually all mining equipment is subject to wear and the resulting deterioration that increases with equipment life. This mechanical deterioration results in lower availability and, thus, decreasing, production. Due to decreasing production and increasing repair costs, there is an optimum age at which the replacement of a given equipment unit with a new unit will result in the lowest cost per unit of production for the equipment operation in question (Figure 1). Determination of this optimum replacement age is further complicated by factors such as: possible overhaul alternatives, fleet replacement and expansion alternatives, remaining life of the mine, and technological improvements in the potential replacement or differences in the production capacities of these replacements. Determination of the optimum time to replace an equipment unit becomes more critical each successive year due to the rising capital costs of new equipment versus maintaining old equipment. An incorrect choice of the replacement age for an equipment unit can result in excessive costs to the mining operation. If a unit is replaced too early, the capital cost of the unit is not fully utilized; conversely, replacing a unit too late results in excessive maintenance costs and low production. The economic life of a piece of equipment is the equipment age that results in the lowest total discounted cost per unit of production for that piece of equipment, not considering the cost of future replacements. The economic life of a piece of equipment is usually shorter than the physical life, the maximum age at which a machine is capable of doing useful work. The optimum replacement age for a piece of mining equipment may vary from the economic life of that equipment due to the remaining life of the mine, fleet considerations, costs associated with potential replacement machines, and capital rationing constraints. For example, the equipment life of the current machine that may result in the lowest cost per unit of production might be 10 years; however, when the timing of the future replacement costs are entered into the calculation, a different life for the current machine might result in the lowest total cost per unit produced for the remaining life of the mine.

Jan 1, 1982

By L. George Imperato

The Blocked Iron Corporation has been active for many years in the development of mineral agglomeration processes by cold chemical induration. Millions of tons of iron ore fines agglomerated by their methods have been consumed in open hearth steel making furnaces. Some of you may remember these open hearth agglomerates as the carbonate-bonded cylindrical block shown in figure 1. With the realization that iron making would create the greatest demand for agglomerates our research efforts were directed to the production of carbonate- bonded (C-B) pellets containing iron ore, flux and carbon, shown in figure 2.

Jan 1, 1968

By Ralph W. Barbaro

This paper presents a cyclic queueing model which evaluates the productivity of a shovel-truck materials haulage system. For a cyclic queueing problem with exponentially distributed service times, a cyclic queueing model provides exact solutions in a fraction of the time that simulation takes to produce an approximate solution. The model is applied to an example problem, and the results are validated with simulation. Simulation is used to show that the assumptions of exponentially distributed service times and steady-state are not serious problems. A cyclic queueing model can be used to quickly obtain an accurate assessment of the productivity of a shovel-truck system.

Jan 1, 1986

By Frank Littlewood

Research over a period of ten years resulted in the development of an efficient automatic ore feed regulator for mill grinding circuits. The facilities that a large mining company gave the inventor made it possible to develop the control apparatus under actual mill operating conditions. The Littlewood Regulator automatically determines the optimum power input at which a mill should operate, and controls the rate of ore feed to maintain this optimum power for any predetermined operating conditions. It is to be noted that the optimum power varies with many factors such as ball, rod, and mill liner wear, therefore the regulator is designed to automaticall keep itself properly calibrated. To efficiently control the rate of ore feed of a mill grinding circuit the regulator analyzes and interprets all power changes of the mill motor. The critical electrical measurements for this type of control are made possible by a patented device that has the ability to detect and integrate minute changes in power. In ball mill operation the small but significant changes in power serve to select the rate of ore feed in accordance with the rate at which ore accumulation takes place within the mill, and in rod mill operation they serve to select the rate of ore feed in accordance with the degree of rod spread.

Jan 1, 1970

By R. L. Grayson

The health and safety of employees, efficiency of the operating system and production are paramount goals in underground coal mining. The section foreman assumes responsibility for making his part of the total system function to meet these goals. However, section foremen often have not been prepared to assume the full range of their responsibilities upon becoming a supervisor. This discussion addresses the full range of section foreman responsibilities and concomitant authority. Management principles that must be mastered by him are presented, and performance expectations as well as criteria for their evaluation are examined. The benefits realized from effective foreman training are discussed.

Jan 1, 1985

By Mehmet Guney

[The Atlantis-II-Deep is a hydrothermal mineralization located along the median valley of the Red Sea at a water depth of about 2200 m. Extensive exploration of the metal-rich brine deep revealed a potentially mineable deposit on economic interest consisting of oxides, silicates and sulphides with considerable concentrations of zinc, copper, cadmium and silver. Geostatistics was applied to assess the most likely in-situ vague of the metal potential for economical exploitation. Semi-variograms were constructed to characterize the structure of the regionalized distribution of the geological parameters. Volume grades and thicknesses were determined by the kriging technique, avoiding systematically biased high or low grades, and then block .tonnages were computed. The estimation variances, distribution of errors and histograms of observed and kriged values in each grid Mock were also produced.]

Jan 1, 1983

By R. L. Hills

America's industry uses about 44% of the total energy consumed by the nation directly as fuel burned in industrial plants or indirectly as fuel burned by utilities to provide electric power. In addition, industry requires raw materials or feed stocks derived from fuel sources or having fuel value. This represents about 11% of total U. S. energy consumption, bringing industry's portion to about 55%. Adding that portion of energy consumption required by the transportation sector to move raw materials, intermediates, and finished products, the total energy impact of industry approaches 213 of total U. S. consumption. It is obvious that American industry has the largest share in the task of balancing energy demand and supply. What are we going to do? -- We must increase the supply of energy and increase the beneficial results obtained from each unit expended. Both avenues, unfortunately, are limited in extent and speed. Increases in supply cannot occur without drastic and permanent increases in cost. These increases in cost are un- desirable and inflationary but do provide incentive for the rational businessman to expend the effort and money required to improve the effectiveness of energy in industry.

Jan 1, 1975

By Thomas V. Falkie

Of the various critics of federal energy and minerals policy we are hearing these days--and they are legion--few make their points more vividly than our fellow SME member and eloquent spokesman for the mineral industry. Mr. Eugene Guccione. In a moment of comparative mellowness. Mr. Guccione recently characterized Washington's time-honored legislative and bureaucratic machinery as a case of "...scientific illiterates asking the incompetents to do the unnecessary." I hope the prevailing industry view of government is not quite that harsh, and yet one cannot deny that government intervention is indeed pressing in on the mineral industry with increasing force. What is happening today in Washington and in state capitols will have enormous impact--both short and long term--on the future of coal and mineral production in the United States. Symptoms of this trend are everywhere. In the first place, there is a sentiment, widely held and still spreading, that the government must become involved-- that no matter what the problem, the solution lies in more government intervention. Free enterprise versus statist, reflex reaction organizations. When it cones to regulation in the resource field, there is too often a tendency to start out by assuming guilt on the part of the mineral industry. This can lead to laws governing mineral recovery that are more punitive than constructive...laws drawn up with little research into the scientific or economic considerations involved.

Jan 1, 1975

By Douglas H. Bolton

In recent years, equipment manufacturers have been busy developing remote control systems to catch up with the sophistication and efficiency of continuous miners. Now the tables are turned, and manufacturers are undertaking the new challenge of upgrading, refining and equipping continuous miners to take full advantage of the capabilities made possible by modern, successful remote control systems. Because the operator can safely advance the miner farther without pulling out for roof bolting, continuous miners now need to be equipped with means of complying with correct face ventilation, dust suppression, methane detection, diffusion and improved lighting. Some of the exciting possibilities being developed to catch up with remote control include feedback controls using laser beams as datum points, coal sensing devices with feedback signals to show the operator what the machine is doing, show where it is relative to the coal seam, how hard it is working, and more sophisticated use of cyclic control. Mining machinery manufacturers have accepted the new challenges, and faster, safer mining procedures are already in sight.

Jan 1, 1975

By A. Andreas

The transportation of mine products incurs a cost which can have a significant bearing on the competitive position of the product. This statement not only holds true for the transportation of the finished product but certainly as much for the in- plant haulage of the raw materials. Extensive literature is available both in North America and Europe on all aspects 02 these questions and to cite only a few of them: Pipelining of slurries, oil and gas, shipping of minerals and oil from the Arctic by icebreaking tankers, airlifting of metals or concentrates, etc. This paper is concerned with movable crushing plants as opposed to stationary and their influence on the in-plant transportation, that is trucks vs. belts.

Jan 1, 1973

By Donald L. Gaughenbaugh

Under the terms of the 1970 amendments to the Clean Air Act, the EPA established national ambient air quality standards for a number of pollutants. Sulfur dioxide (SO2) was one of these pollutants. These ambient air quality standards have had perhaps their biggest impact on the power utilities. In an effort to meet the air quality standards set forth by the EPA, utilities using high sulfur fuels have been forced to install flue gas desulfurization (FGD) systems. The majority of FGD systems in operation today are nonregenerable systems, that is the by-product of the system is disposed of, usually into settling ponds. Limestone slurry is the most common reagent used to remove SO from the flue gases. The calcium carbonate (limestone) slurry interacts with the flue gas, absorbing the SO2 and forming a by-product of calcium sulfate/sulfite which is disposed of.

Jan 1, 1986

By R. S. Shepard

A quick glance at a-portion of the title of this discussion -'Rolling With The Punch" may immediately lead you to assume that I am about to expound on the so-called manly art of self-defense. So that you will not have been misled entirely we will devote our considerations to a far more important art and if I may, I should like to begin by quoting Vincent Van Gogh. According to a literal translation the artist in describing one of his famous paintings said "these peasants are eating their potatoes with those very hands that dug them from the earth' and put them in the dish". Vincent Van Gogh may not have realized at that time, that he could likewise have been describing what is probably one of the oldest of all arts - the art of Material Handling - an art that man with the aid of science has tried to improve since the beginning of time.

Jan 1, 1963