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By Edgar F. Cruft

It is sometimes said that "mines are made, and not found". I rather doubt that the exploration geologist would be overly sympathetic to that statement, and, of course, like most one-liners it is only partly true. As an explorationist who has been involved in building his own company over the last ten years, and by necessity has become a financier, I can appreciate what real grains of truth are in that statement, however. Because technical people are seldom taught financing in their basic training, and because they are usually not involved in it until at quite a senior level in their careers, the whole field often acquires a certain mystique. The engineering professions have too often believed financing is the province of the accountant or financial executive and just as we in the technical world are often too quick to bristle if the latter try to tread on our domain, the opposite can just as easily be true. Unfortunately, this is another example of a compartmentalized individual, and that is one thing the successful financier cannot be.

Jan 1, 1979

By R. R. Young

Prior to 1903, the world's supply of sulphur was primarily from surface deposits in Sicily. The discovery of the first salt dome sulphur deposit in 1867 and successful development of the Frasch process for recovering the sulphur resulted in a large part of this essential element being supplied from these mines since 1920. Although the basic process is the same today, engineering and technological developments have evolved to allow its application under many adverse conditions. These and other challenges for the industry in today's environment will be discussed in the paper.

Jan 1, 1979

By Donald P. Richards

Is a shaft the same as a tunnel and can it be approached in the same manner for design and construction? The most obvious difference between a shaft and a tunnel is that of orientation; whereas a tunnel is commonly near horizontal or slightly dipping, a shaft is commonly vertical or steeply inclined. As a result, design and construction methods employed for tunneling, in general, cannot be directly applied to shafts, although some of the basic concepts of behavior are quite similar. Many of the shafts that have been sunk in various parts of the world are owned by private mining companies. Each company has generally accumulated years of experience in shaft sinking and mining techniques pertinent to its particular geographic location. When a new shaft is to be sunk or an existing shaft deepened, the tendency often seems to be to continue to use the methods that have been used successfully in the past.

Jan 1, 1979

By W. E. Bardelmeier

The high speed conveyor type self unloading bulk carrier concept has been around for about 70 years. Although the design was developed, refined and steadily improved in the Great Lakes, to date limited numbers of such vessels have emerged in the bulk ocean trades, and these have tended to concentrate within specific mineral trades. For example, North American gypsum companies have embraced conveyor self unloaders to the point where such vessels almost exclusively carry the gypsum requirements of this part of the world. One major aluminum company has developed an impressive fleet capability in self unloaders. Application of other ships tends to be fragmented through several mineral trades. A few years ago a new phenomonen began to appear on the Great Lakes. Whereas it had historically been accepted in that region that self unloaders were effective vessels for the minor bulk trades including limestone, coal, salt, gravel and sand; they had seldom been employed heavily in the big volume iron ore trades. Suddenly, however, the new generation of 60,000 ton Lakers which emerged were all designed as high speed self unloaders. The new vessels intended to trade especially in ore, or alternatively especially in coal, have somewhat different internal features, but the important point is that all are self unloaders.

Jan 1, 1979

By Konrad J. Banaszak

At least for the time being, these seems to be general but not universal agreement that Mississippi Valley type ore deposits formed entirely or in major proportion from heated connate brines (e.g. 1) Even with that agreement, major questions remain. I will present a coherent geochemical model and look at alternative views in the context of that model. The pattern of the following discussion is 1) the general geochemistry of the ore fluid, 2) the density-temperature relations and possible mechanisms of flow of those fluids, 3) the mechanisms of transportation and deposition of the ore minerals, and 4) a summary of a coherent model of genesis. The data equivocally define much about the deposits. The answer is still elusive.

Jan 1, 1979

By Roderick K. Davey

Kennecott Copper Corp.'s Metal Mining Div. operates three major open-pit copper mines in the western United States. These operations include Utah Copper Div., Ray Mines Div. in Arizona, and Chino Mines Div. in New Mexico. At each of these operations, the material is loaded by large electric shovels and transported by both truck and rail haulage. In 1977, 197 350 774 t (217,542,000 st) of ore and waste were mined at these operations, and 302 040 t (332,942 st) of copper were produced. Also a significant amount of molybdenite was produced as a byproduct. In operations as complex and large as these, there is an inherent need for up-to-date reports concerning how much material was mined during the previous day, and year-to-date, what equipment is scheduled for maintenance, how equipment has been performing, etc.

Jan 1, 1979

By F. L. Wilke

Underground mining is a very complicated and complex industrial activity. The uncertain and, in most cases, the incomplete knowledge of the geological and mineralogical nature of the deposits can cause unforeseen difficulties. For a safe and uninterrupted operation, in addition to good planning and scheduling, reliable and up-to-date monitoring and control of all processes and conditions become necessary. Today, this is even more important in view of increasingly difficult working conditions, poorer grades, and more complex and expensive machinery. In short, large capital investment and higher risk of financial losses are involved in modern-day mining operations. Monitoring and control of the underground mining process has become a very complex and difficult task in itself. Many different systems are available, and the correct choice .is of utmost importance from both the economic and safety points of view. This chapter will deal with aspects of underground production monitoring and control. There are, however, many other areas of equal importance which are covered in an excellent manner in a hand- book by Olaf (1976) on monitoring and control of underground operations.

Jan 1, 1979

By Don Minard

Management support systems are extremely important to mining management to enable them to operate their company as a business. Management must give attention to the financial, maintenance, materials, and other reporting and control systems that are necessary to successfully operate a mining company. This subsection describes the management support systems that are critical to most mining companies. In this introductory review, the major objectives and functions of these management support systems will be introduced. The following topics will expand on the functions and key concepts as well as other considerations in each of these systems areas. Additionally, this introductory review will touch upon the unique environment that mining companies find themselves in from a management and personnel standpoint and the effect of this environment on management systems. Additionally, specific keys to successful systems installations and acceptance in the mining industry are discussed.

Jan 1, 1979

Tyre costs constitute 20-40 per cent of the operating cost of large haulage trucks, and tyre pressure maintenance is an important factor in minimizing costs.In the past, control over the hot (built-up) pressures of earthmover tyres has been inaccurate and inconsistent because it has not been possible, in a practical way, to measure the tyre's contained air temperature.A method for measuring this contained air temperature has now been devised using a bi-metallic probe thermometer inserted through the valve stem. Using these measurements in conjunction with a pressuretemperaturechart drawn up using the general gas equation, very accurate control over hot tyre pressures is now possible.

Jan 1, 1979

By Steven A. Elmquist

Although past investigations (2, 5)have been conducted to determine crushing relationships, no program which covered a broad range of crushing conditions had been conducted. The previous studies appear to concentrate on small segments of the overall picture and did not fullfill our desired information objectives. The Crusher Variables Research Program conducted at the Mineral Research and Test Center (MRTC) of Rexnord, due to the broad range of variables utilized in a production size crusher, is believed to be the most comprehensive study of its kind as of this date. The principles developed by the Symons brothers in 1925, when they patented the cone crusher as we know it today, are still being used in the machine known as the Symons Cone Crusher, During the development of this novel crushing concept, a technique known as the fall of material (called the Bouncing Ball Theory1 by some) was used to determine an idea as to the proper head angle, eccentric and speed of eccentric rotation, The final variables used for the Symons Cone Crusher design were, therefore, the logical conditions to start with and use as a reference against which other variables could be compared.

Jan 1, 1979

By Roderick K. Davey

The objective is to develop a short-range mining plan which satisfies management and operating criteria and also "dovetails" with the long-range mining plan. In the past years, this objective was accomplished entirely by manual methods. Today, the computer is used to assist the engineer with this task. The results provided by these programs usually are incomplete and require further manual manipulation. The advantage of using the computer programs is that the program can be used to evaluate alternative plans on a first-cut basis minimizing the manual work. Subsequently, the most promising alternatives can be analyzed in more detail, commencing with the first-cut results. In this specific case history, one technique for using computer programs to assist with short-range mine planning will be discussed. Some of the basic operating and management criteria considered directly and indirectly are as follows: (1) operating criteria which include minimum and maximum shovel cut size, equipment performance, haulage roads, requirements for blending, and plant capacities; and (2) management criteria which consist of production requirements, cash flow requirements, return on investment, market demands, and availability of capital.

Jan 1, 1979

By Richard A. Bideaux

In mid-1975, the United States Borax & Chemical Corp., a member of the RTZ group, engaged Computing Associates, Inc. (CAI) in a continuing project to model their operating property at Boron, CA, with the goal of computerized assistance in medium- and long-range open-pit mine planning. Their property, 161 km (100 miles) northeast of Los Angeles, is the largest producer of borate minerals in the world. Because of unusual geological complexity, this unique deposit presents interesting problems in computer modeling, compared with the coal, uranium, and other metallic deposits with which CAI ordinary deals. Mine planning for Boron has historically been based on manually plotted contour plan maps and cross sections, with geological reserves derived from manual triangularization of the drilling pattern. Standardization and reproducibility of log interpretation, contouring, and reserve calculation were principal goals of using the computer. Additionally, it was desired to shorten both the time and cost of a planning cycle, while at least equalling the accuracy of the manual planning. The present recovery plant processes only water-soluble borates; at some time in the future it will be necessary to recover acid-soluble borate minerals as well. With computer assistance the economics of this changeover point can be more thoroughly evaluated.

Jan 1, 1979

By L. H. E. Weyher

The Bethlehem Mines Corp. is a captive mining subsidiary of Bethlehem Steel Corp. Its coal production is tied to the demands for and production of steel, a situation that has to balance between the following two extreme strategies: (1) either the mines are designed and operated for some optimum production level and the demand fluctuations within the steel corporation are met by supplementary corporate coal sales and purchases, or (2) the mines absorb all the demand fluctuations, regardless of the effects on mine costs. A rational definition of the best strategy between these extremes is, of course, needed but is very difficult to formulate in view of the complexity of the many factors that would have to be included in the analysis. Consequently, rather than setting profit targets for each given mining division and/or individual mine, the practice evolved to set production targets for producing specified tonnages of coking coal for shipments to the ovens located at the corporation's iron and steelmaking plants. This in turn leaves the mines with the dilemma of having to explain demand-related cost-per-ton fluctuations while essentially depriving them of the ability to control profit through tonnage optimization. In the early 1970's, the coal prices rose significantly, while other factors led to sagging productivity in underground coal mining. Thus, the role of Bethlehem's coal operations in the corporate profit picture gained in relative importance. This, in turn, sparked a closer attention to the coal mining cost structure and factors controlling productivity. At the same time, the drastic increase in the capital needed to open a new mine also increased the amount of planning required to minimize risks. All of this called for more well-defined, quantitative operating data. Bethlehem therefore launched, in the early 1970's, a number of innovative steps that, as the future may show, represented pioneering contributions to the growing sophistication of North American underground coal mine planning and management control practices. This case study describes the changes that led to the current implementation of a novel production reporting system at Bethlehem's coal mines. These changes took place in two distinctly different phases. The current system that resulted from the Phase II developments utilizes, of course, experience gained earlier and is expected to be amplified to incorporate more advanced concepts and technology as future experience dictates.

Jan 1, 1979

By Christopher Haycocks

Because of growing pressure from government and consumers to produce more coal, the mining industry must improve existing techniques and devise more efficient mining methods. Mining of the thicker, shallower and geologically superior coal seams in the western United States is being subjected to increasing pressure from environmentalists; and so in order to meet the demand, the coal industry is exhausting the more accessible surface seams and beginning to mine seam of over 1,000 feet in depth and less than. 30 inches in thickness. The longwall mining system is the natural choice for extracting deep and thin coal seams, as it operates almost independently of the overburden rock stress. Due to the added fact that longwall mining is an inherently more productive method than room and pillar mining, many coal producers are looking to it as a means of increasing productivity without a corresponding cost increase. The consistent rise in application of longwall mining in the United States in the last decade illustrates the excellent potential of this technique for the future. American mining conditions are geologically different from those in Europe where longwall mining has been highly developed and extremely successful. Although numerous successes have been recorded in the U.S. with this mining system, a substantial number of failures have also occurred. These failures are due primarily to roof control problems usually over the face, in the tail entry, or both. Another problem area for American operators contemplating the use of this method has been correct selection of equipment, which should be custom fitted to local mining conditions for optimum productivity. It is essential that correct estimates for chock resistances, support densities, supported and unsupported roof spans, as well as rates of advance and length of working faces be provided to optimize mining conditions. Unless extensive pilot projects are planned engineers must choose their equipment correctly at the outset. A typical investment in longwall equipment will amount to several millions of dollars.

Jan 1, 1979

By Richard C. Fox

"Why geophysics? We will have to drill anyway." Reliance on geophysical methods for detailed target appraisals will increase as direct surface evidence becomes more subtle. This will create a need for more effective and efficient geo- physical programs. Numerous computer-based techniques that deal with a broad range of geophysical problems are described in the literature. The purpose of this chapter is to provide a framework for the systematic application of these techniques to effect an overall optimization of the geophysical appraisal. The concepts described are not technique specific, but should serve as a guide for increasing the effectiveness and efficiency of any geophysical program. Fig. 1 shows a generalized flow chart of the major aspects of the program described. The three main subdivisions of a 'geophysical program are discussed: (1) survey design, (2) data processing, and (3) data interpretation. Detailed flow charts, outlining the goals, the requirements for meeting the goals, and the steps followed within each subdivision are presented at the beginning of each section. The objectives and type problems of each subdivision are defined, followed by a description of applicable computer methods. . References are cited that give a general cross section of computer techniques available in the literature, and examples are given in each subdivision to demonstrate basic concepts and the use. of computers in solving the type problems.

Jan 1, 1979

By Thomas L. Kesler

Lithium raw materials usable with present technology consist of pegmatite ore and shallow evaporite brine. Deposits of these materials occur in many parts of the world. Those advantageously located supply the present lithium industry. Less favorably located deposits will come into production as markets expand and present sources are depleted. In this discussion, materials listed as reserves include fully explored and partly explored deposits. For those closely drilled and assayed, the data provide measurements rather than estimates, and such reserve tonnages are "proved." For deposits partly explored, the data support reserve estimates of "probable" tonnages. Materials lacking exploratory data are classed as resources, and their "possible" tonnages are inferred mostly from indirect evidence and are essentially objectives for exploration. All figures for pegmatite ore apply to total materials in the ground.

Jan 1, 1979

By Rolf Lange

Introduction The Harzwasserwerke, a public body of the Federal State of Lower Saxony, supplies drinking water to an area bordered by Braunschweig, Bremen, the Northern and the Western edges of the Harz-Mountains. From the very beginning in 1928, the Harzwasserwerke have been systematically constructing reservoirs in the western Harz which have the function of collecting and storing the frequently occuring flood waters as well as providing drinking water. The Grane-Reservoir with a capacity of 45 Million cu.m., the last of the big reservoirs, was built in 1968-1970. A system of connecting tunnels effectively enlarges the natural catchment area of this reservoir and the surplus waters of the Oker and Radau valleys - where floods occur particularly during the spring - are being conducted to the reservoir. By building the 4.800 m long "Radau-Tunnel", the waters of the Radau valley will now also be used more efficiently and its surplus waters will pass to the Grane Reservoir via this new tunnel and the Oker-Grane-Tunnel which was finished in 1970. The Project The Radaustollen has been planned and put out to tender by the Harzwasserwerke as a conventional "Freispiegelstollen". The horseshoe profile has a cross-section of 8 m2. Lining was required only in disturbed rock areas; lining of the whole tunnel was not necessary. The gradient of the tunnel is 4 % 0 rising = 25 m over the total length of 4.800 m.

Jan 1, 1979

By R. H. Nafziger

Bureau of Mines research has shown that very low-sulfur pressure vessel steels with improved mechanical properties can be prepared by two melting processes. Four pressure vessel steels having sulfur contents ranging from 0.0008 to 0.0040 wt-pct, were produced by the electric-arc furnace or by the electroslag processes. Calcium carbide was used as a desulfurizer in the electricarc furnace. Fluxes containing at least 40 wt-pct CaO provided sufficient desulfurization during electroslag remelting. Element recoveries were higher for electroslag remelting than for metal melted in the electric-arc furnace. Bar rolled from electroslag-remelted ingots generally possessed higher tensile strengths and ductility than bar rolled from it t melted in the electric-arc furnace. Charpy V-Notch upper shelf energies were also improved as a result of electroslag remelting. The primary failure mode during impact testing was was microvoid coalescence. Sulfide inclusions were minimal, especially in the electroslag-remelted material.

Jan 1, 1979

By William C. McBee

Specialized sulfur concretes were developed by the Federal Bureau of Mines as a result of research for the beneficial utilization of sulfur in construction materials. Materials were developed for use in acid and salt corrosive environments where portland cement concrete has been found to deteriorate. Because the mineral aggregates also come into contact with the corrosive media, concretes were developed utilizing both limestone and quartz aggregates. The sulfur binder used with both aggregates was modified by reaction with 5 pct dicyclopentadiene to improve product durability. Sulfur quartz aggregate concrete was found to have moderately high strength characteristics (6,000 psi compressive) and was extremely resistant to chemical attack by both acid and salt solutions. Sulfur limestone aggregate concrete exhibited very high strength characteristics (9,000 psi compressive) and was extremely resistant to chemical attack of salt solutions. Both types of concretes maintained their strength and integrity after long-term testing in acid and salt solutions and exhibited considerable resistance to damage by the action of freezing and thawing. Potential uses include leach tanks, electrolytic cells, thickeners, bridge decking, industrial flooring, pipe, and tile.

Jan 1, 1979

By C. Haycocks

In spite of the increasingly high capital investment required for longwall mining equipment, there continues to be a steady trend towards this form of mining. This move is caused in large part by improved productivity of longwall mining systems combined with greater percentage of coal recovered over room and pillar mining, reduced manpower requirements, and the inherent safety of the system. Longwall mining is most amenable to the greater depths experienced by many mining operations, particularly in the coalfields of the Eastern United States. Two primary problems in the installation of a longwall panel are determining whether a particular seam is suitable for longwall and, secondly, type and capacity of equipment required for such a mining operation. In addition, recent legislation has forced an evaluation of the surface effects of longwall mining with a view to determining what, if any, surface damage might result from extracting any particular panel. These factors must be determined using large and often complex quantities of geological, structural, mining, and surface data. This makes the problem most attractive to solution using the computer.

Jan 1, 1979