Search Documents

By Don Opacic

The disposal of sludges and other similar industrial wastes is a major problem. Liquid wastes from industrial operations, when treated, produce significant volumes of sludge which are difficult to dispose of, because of the chemical and physical properties of the sludge. In the mining industry sludge is produced from various water treatment operations, in particular mine drainage neutralization. Waste water from coal preparation plants also produces a sludge however the sludge is in fact a slurry containing clays, coal fines and coal impurities. In many areas the disposal of these sludges is producing a serious problem. Mine drainage sludge consists of a variety of hydrous iron oxides, usually ferric oxides, contaminated with other neutralization products such as calcium sulfate. The volume of sludge from mine water or mine

Jan 1, 1973

By R. Allan Wallis

In the past mining engineers have tended to rely heavily on the advice of fan manufacturers in relation to fan equipment issues. A more adequate approach was advocated in a paper [ Wallis, 1965 ] submitted to the Eighth Commonwealth Mining and Metallurgical Congress held at Surfers Paradise, Australia during 1965. At that time Mount Isa Mine were in the process of installing 3 large 6096mm (20ft) diameter vertical axial flow surface fans of an advanced type [ Mathews et al, 1967 ]. The preliminary feasibility studies prior to preparing the detailed job specification for this project were extremely thorough with the result that it was possible to include detailed information and instructions in the document, ensuring the procurement of equipment that was satisfactory in all respects. Full advantage was taken of expert services provided by external organizations during the large coordinated multi-disciplinary exercise. My continuing activity and development in relation to the technology of axial flow fans is now at a stage where all known design and performance data are accessible through CAD programs [ Wallis and Kipp, 1987 ]. The extensive calculations that were necessary in 1983 can now be carried out in a mere fraction of the time, and with complete confidence. Model testing in order to validate the fan and duct design proposals is, in my view, no longer essential. The first of the computer programs enables a mine ventilation engineer to study a large number of alternative axial fan arrangements for comparison with the centrifugal alternative. By entering the volume flow rate, fan pressure and air density, he can then with ease, and rapidly, investigate the effect of various blading arrangements, downstream evasee area ratios, and hub ratios, on fan diameter and speed, with their related attainable fan efficiencies. This procedure had its origin back in the 60s when I was advising mining companies on new fan equipment. At that time such an investigation was quite lengthy and lacked the precision and completeness that is now available within the present programs. To obtain the major benefit from these outputs, it is most important not to be disconcerted by the three very important nondimensional parameters, namely, the tip flow coefficient (LAMt), the fan pressure coefficient (Kt or Kit), and the swirl coefficient (Es and/or Ep) as these are important when assessing the various design proposals. When seeking an understanding of the role and importance of each of these variables, ample help is provided in the user manual; the design recommendations are summarized in the help screens which are readily accessible within the design programs.

Jan 1, 1989

By Raymond E. Kary, John W. Mcklveen

The four unit Cholla coal fired power station at Joseph City, Arizona, consumes coal from the McKinley mine located in western New Mexico. Since coals may contain relatively high uranium or thorium concentrations and may release quantities of detrimental progeny of these elements to the environs, there is concern that releases may pose an adverse environmental impact or even a health hazard to the workers. Thus, an effort was made to quantify the radionuclide content of the coal and compare the results with radionuclide concentrations already present in the vicinity of the plant. Additionally an attempt was made to assess any potential for significant enhancement of the levels of radioactivity in the environment or to plant personnel. Background gamma radiation measurements at and near the plant ranged from 8 to 12 [µ]R/hr (70 to 105 mR/yr) with a few localized anomolies measuring to 18 [u]R/hr (160 mR/yr). Levels on top of the coal storage piles decreased to ~ 6.5 [u]R/hr (60 mR/yr). Apparently the direct radiation emitted from the coal is less than the background levels in the vicinity of the plant. Measurements performed on top of several coal seams at the mine confirmed low radiation levels emanating from coal, but readings more than doubled when the overburden was monitored. Laboratory gamma spectrometry confirmed the lower amounts of natural radioactivity in the coal when compared against soil and water samples obtained in the vicinity of the plant and the overburden at the mine. In an effort to see if there is biological enhancement, animal feces was sampled. The radiation variations were found to be influenced primarily by naturally occurring potassium-40 which varied from ~ 1 to 18 pCi/gm rather than fluctuations in the uranium and thorium series. The potassium-40 concentrated in the ash were similar to the concentrations in the environs around the disposal ponds while Radium-226 concentrated in the fly ash was ~ 3 times that found in the immediate surroundings. Radon-222 gas concentrations in buildings at or near the plant ranged from 0.5 to 1.8 pCi/l and were generally lower than indoor concentrations measured in the Phoenix area. The burning of coal at the Cholla station does not appear to increase ambient levels of radioactivity found in the surrounding environs or to the workers. However, the use of byproduct fly ash for construction purposes may need to be examined.

Jan 1, 1981

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 Robert W. Miller

There are many problems faced by ventilation engineers in deep underground mining operations, not the least of which is controlling miner exposure to radon gas and its daughter products. Radon gas is commonly found in uranium mining operations, but may also be present in other deep metal mines. For example, tin mines in England, iron ore mines in Sweden, gold mines in South Africa, and molybdenum mines in the U. S. have potential radon exposures. This is because uranium and accompanying radium ore are ubiquitous to the earth's crust albeit at low levels. The fact that the activity represented by one WL can be caused by a relatively low concentration of radon gas increases the difficulty of control. Since the source of the radon gas is usually widespread throughout a mine, local exhaust ventilation is not a viable control schema. The technique used to control exposure is then dilution ventilation and, in fact, huge amounts of air must be moved in order to reduce potential exposures to an acceptable level. An interesting comparison can be made of ventilation rates in different types of mines. It is estimated in modern coal mines, which are generally acknowledged to have high rates of ventilation, that about eleven tons of air are moved for each ton of ore mined. A typical operating uranium mine may have ventilation flows of 14-15 tons per ton of ore mined. This provides an idea of the scope and importance of ventilation in modern mining operations where radon is a hazard. Further pressure is put on ventilation engineers by the steady downward trend in exposure limits set by national and international standard setting agencies. Much of this tendency toward lowered standards is based upon longitudinal mortality studies of miner populations. Another important factor is the limited number of experienced miners available in the labor pool. For optimum production, it is important to have as many experienced miners underground in each shift as possible. However, the average daily exposure in a U. S. mine must be less than .3 WL to permit the miner to work underground for a full year. The ventilation system then must provide enough uncontaminated air to maintain the WL below the .3 TTL level to maximize production efficiency and minimize personnel turnover and the problems associated with it. Ultimately, the goal of the ventilation engineer and health physicist is to protect the working miner from harmful exposures based upon currently acceptable standards. U. S. Federal regulations require that in uranium mines all active work sites must be monitored every two weeks if they measure above .1 WL. Areas that have .3 WL ratios or higher must be monitored on a weekly basis until five consecutive weekly samples show the level has dropped below .3 WL. Also, exposure records must be kept for all individuals exposed to levels exceeding .3 WL. These requirements provide a strong economic incentive to have a ventilation system that minimizes exposure of any personnel. A good ventilation system requires careful planning, operation and backup in order to fulfill its mission of providing adequate clean air. Its proper operation also requires coordination with production personnel so it can be adapted as new areas in the mine open up and old areas are sealed off. The ultimate indicator of ventilation efficiency to control radon daughter exposure is, of course, monitoring working levels. Historically, this has been done using the Kusnetz, Tsivoglou, and Rolle's methods, among others. These methods all require cumbersome equipment and tedious calculations to obtain the measurements that results in WL. More important, however, they require a significant time lag between sampling and counting, typically 40-90 minutes. This time lag is, in fact, what can cause significant economic losses due to unnecessary downtime as well as high WL exposures. In a typical mining situation, a sampling technician using the Kusnetz method takes a sample, moves to the next location and takes another sample and so on. Forty to ninety minutes after the first sample, the technician will stop, run the activity count on the filter and calculate the WL. The technician may be one-half mile away or several levels removed from where the first sample was taken when it is counted. If the WL ratio is high the technician must then backtrack to the sample position. There are then two options. If the sample area is a working stage, it can be shut down or a second sample can be taken. If the first alternative is chosen; i.e., shutdown and correction of the ventilation, then another sample must be taken, followed by a forty minute wait for results. If the ventilation adjustment didn't correct the problem, then the whole process must be repeated with a minimum of forty-five minutes per sample cycle when using the Kusnetz method. It has been estimated from operating uranium mines that the cost per hour for downtime on a production slope is about $1,50O/hour. The time lag between sampling and resultant data can be very costly. If the second alternative is chosen to verify the first reading, the miners may be unnecessarily exposed to high levels while waiting for the result. Clearly, such a sampling system can be markedly improved by eliminating the excessive time lag between sampling and analysis.

Jan 1, 1981

By Stephen R. Hunt

This paper summarizes some preliminary results of the Illinois State Geological Surveys current investigation into surface subsidence resulting from coal mining in Illinois. The purpose of the study is to characterize-the vertical movements that may result from various types of underground coal mining. In general there is relatively little published information about subsidence from room-and-pillar mining as compared with longwall mining. The findings of this study, based on mining operations in a variety of geologic settings, delineate the magnitude, shape, and position of the subsidence profile. Comparisons of case histories of subsidence are based primarily on the extraction ratio and the general geometry of the mine (depth, panel width, and mining height).

Jan 1, 1979

By Paul Soros

A major share of the increase in the energy demands of Ontario province in the next decade will be supplied by bituminous coal mined in the U,S, To be competitive with alternative sources of energy, it is essential that the delivered cost of coal, inclusive of all transportation charges, be kept at a minimum. The Bessemer aid Lake Erie Railroad Company and the Pittsburgh and Conneaut Dock Company are currently building a shiploading terminal at Conneaut, Ohio, to service this tonnage, together with expected increases in coal consumption in the Eastern Lake Erie - Lake Ontario area, (see Fig, 1).

Jan 1, 1965

By R. A. Hill

A brief explanation of the theoretical functioning of a regenerative system followed by its application to firstly, shuttlecars and then continuous miners and its effect on performance thereof with regard to handling, production and safety.

Jan 1, 1986

By G. E. McClelland

Introduction Many discoveries have been made during the-past decade of low grade gold-silver deposits in the western US. This has stimulated development of low cost cyanidation procedures for precious metal extraction. Heap leach cyanidation techniques possess considerable potential for application to these low grade ores, small ore bodies, mine strip waste, and tailing materials where fine grinding is not necessary for good extraction. For heap leaching to be successful, these resources must have good permeability to achieve uniform distribution of the cyanide solution throughout the heaps. Some of the most difficult of the gold and silver ores to treat successfully by heap leaching are those containing excessive amounts of clays, or fines generated by crushing. Presence of excessive amounts of slimes, -50 µm (-270 mesh), in the heap leach feed will slow percolation, cause channeling, or produce dormant or unleached areas within the heap. This may result in unreasonably long leaching periods and poor extractions. In extreme cases, the clays or slimes can completely seal the ore heap. This causes the leach solution to run off the sides of the heap rather than penetrate the ore bed. The problem of heap leaching ores with fines can be aggravated while preparing ore heaps because of the natural sorting of coarse and fine material that occurs. This phenomenon results in concentration or ore fines in the center of individual ore piles and concentration of larger rock fragments of the lower slopes and base of the pile. When the individual piles within the heap are leveled off for the installation of the sprinkling system, additional segregation occurs as the fines sift through the coarser ore particles. This results in localized areas or zones with marked differences in permeability. Consequently, the leach solutions follow the course of least resistance. They percolate down through the coarse ore regions and bypass or barely wet areas that contain large amounts of fines or slimes. Effective use of marginal gold and silver resources by heap leaching required development of new methods to achieve more uniform size distribution when preparing ore heaps and better slime control during leaching. Early methods Agglomeration and balling of crushed ore to produce a porous and more uniform feed material for heap leaching is a viable method for treating clayey ores. Researchers from the US Bureau of Mines in Reno, NV began agglomeration pretreatment research in the mid-1970s for applications to and exploitation of these poor percolating feed materials. Little attention had been given to such methods before the Bureau's research. In 1905, T. C. Scrutton developed a unique technique for obtaining rapid vat leaching of a clayey ore where the gold was finely disseminated. His technique consisted of rolling the ore down a chute inclined at 60° to form agglomerates or balls readily permeable by the cyanide solution. However, these agglomerates lacked rigidity. And, to ensure good percolation leaching and washing, they could not be bedded in layers more than 1 m (3 ft) deep. If this depth was exceeded, it is difficult to obtain uniform leaching and washing. This results in reduced gold recovery. Shepard and others in 1937 studied the addition of lime and carbon dioxide or calcium carbonate to gold-bearing tailings to form agglomerates suitable for vat leaching. Satisfactory percolation flow rates were achieved in 90 g (3 oz) scale experiments, but the reagent requirements were cost prohibitive. Agglomeration and pelletizing has been used in other segments of the mineral industry. This technique was first used successfully around 1911 for pelletizing iron ores. Since then, agglomeration

Jan 7, 1986

By C. H. Cox

The Alumet Company of Golden, Colorado, is currently engaged in the development of their Diamond Creek and Lanes Creek phosphate ore bodies located near Soda Springs, Idaho. The Alumet Company is a partnership of National Steel, Southwire Co., and Earth Science Inc. Davy Powergas, Inc., of Florida was contracted by Alumet to perform an evaluation study of these properties and, in general, determine the tonnage of altered and unaltered phosphate reserves which would be amenable to beneficiation and production of merchantable phosphate rock (defined as material with a P2O5 content of 3 1.0% and greater). The Colorado School of Mines Research Institute was retained by Davy Powergas to develop a beneficiation method for the studies of the altered and unaltered ores. Ore reserves were classified by Davy in a comprehensive range of categories such that any partial grouping could be made as dictated by future mine planning, mine or mill design, or prevalent economic conditions. Categories included ore horizon, stripping ratio, degree of certainty of their existence, and physical and chemical characteristics. The last category was of interest for beneficiation considerations in that it dealt with the degree of alteration of the phosphate ore.

Jan 1, 1979

By L. W. Teal

The Paupers Dream Property is located in the northern Boulder Mountains, southwestern Montana, 30 km southwest of Helena. The property is situated in the central portion of the Butte-Helena gold belt, a NE trending lineament marking a zone of recurrent, late-Cretaceous to mid-Tertiary volcanic activity. Geology consists of a plutonic basement of late-Cretaceous quartz monzonite overlain by a pre-volcanic basal conglomerate and a complex sequence of Oligocene rhyolitic volcanics. Gold mineralization occurs in fracture-controlled quartz veins, silicified stockwork, and brecciated shear zones as auriferous pyrite, arsenopyrite, and disseminated free gold. An estimated 60,000 tonnes averaging 2.5 g/t was produced from the Porphyry Dike, Venus, and Paupers Dream Mines on the property. Current drill indicated reserves (May, 19861 are placed at 6,946,000 tonnes averaging 1.45 g/t gold.

Jan 1, 1987

By W. G. Lacy

Anticipation of problems and the adoption of corrective measures in the design of engineering structures, establishment of pertinent building codes, and urban planning and zoning to obtain optimum land usage and conservation of natural resources demands a thorough understanding of geological conditions of a developing urban area. In the and to semi-arid southwestern United States erosional and depositional processes result in special situations that require special precautions in building practices. A series of studies currently underway in the Tucson area prompted by foundation failures and breaking, of buried service lines serve to illustrate some of these relationships between the geological environment and history, and engineering problems.

Jan 1, 1963

By Betty L. Gibbs, Jean A. Arcamone

Introduction Microcomputers are becoming more convenient to use at all levels in the business world, including the mining industry. The state of the mining industry requires that we become more productive and innovative in our analysis of deposits and operations. With the help of computers, examination of options to increase productivity can be performed quickly and inexpensively. Effective computer use to design underground workings combines the calculating power and speed of a computer with the technical expertise and judgment of an engineer. Computer programs can perform in minutes calculations that might take several months for an engineer. But the engineer must be on guard when using computers for calculations. It is easy to assume the results produced by a computer program are always correct. However, the computer is only a sophisticated calculator. It cannot recognize logical errors or transposition of numbers. Also, some intuitive or obvious decisions made by an engineer are difficult or impossible to program effectively. In this article, selected commercial programs are discussed. These programs can provide engineers with tools to evaluate engineering designs for underground mines. The programs perform much of the tedious calculation. The engineer, though, must still make decisions and conceptualize designs. The software mentioned in this article runs on microcomputers and minicomputers. The mention of particular software, however, does not imply endorsement. Mining projects After a decision has been made to proceed with an underground mining project, more detailed evaluation of the mining method and extraction sequence begins. If a mine is already in operation, schedules and plans are needed to more clearly define future production. Existing operations can benefit from identification of bottlenecks in material movement and produce extraction options to make the mine more efficient. Detailed studies for a new mine are based on the technical engineering design. These studies provide specific details to determine equipment requirements. Detailed studies done during a project are similar to short-term planning and control carried out daily by the mining engineers. The engineering design phase includes: • Study of the infrastructures - entries, shaft, access from surface to underground; • Definition of the mine layout, hydrogeology, geotechnical considerations, transport, and ventilation; • Choice of machines and equipment; • Mine scheduling, including waste extraction and production sequencing; and • Economics, including labor and supplies. Further detailed studies include: • Blasting patterns; • Detailed geotechnical calculations; • Secondary ventilation; and • Production cycles along with coordination of the workings. Objectives The primary objective of underground mine planning is moving material out of the mine at the least cost. Development of the production schedule considers location and volume of ore units, transport distance, equipment and manpower interactions, and grade or quality of material. Two methods can be used to determine the scheduled material removal: optimization or trial and error. The microcomputer programs discussed here do not cover optimization for underground mine planning. For several reasons, optimization is often a "black box" approach. Although optimization is possible with linear programming techniques, few mining operations can be described effectively with linear equations. An interactive trial-and-error approach is desirable because engineering judgment can be inserted as a plan develops. Because of the large number of factors in an underground operation, an optimization technique seldom covers all possibilities. Few of the programs available consider all of the possible parameters. The programs use an interactive sequencing or a simulation approach and are either event-oriented or deposit-oriented. The most desirable programs offer an integrated approach. They consider a broad range of operating conditions including equipment, labor, costs, material movement, timing, and mine layout, among other factors. The two types of models generally used in designing underground workings include: • The interactive model, which requires direct, incremental input from the user. Outlines of the section to be mined may show on the screen. The engineer causes the model to develop piece-by-piece. The program may offer feedback on parameters such as tons and grade, or other values, as the section is "mined." • The simulation model, which is usually an automatic technique. Parameters related to the process are entered. The program then calculates the mining sequence over a designated time period or until the economic material is exhausted. A simulation model imitates step-by-step performance of equipment or other processes.

Jan 3, 1988

Introduction Surface mining is a business, and the objective of most businesses is to make as much money as possible within certain responsible constraints. Businesses normally measure their potential to make money by estimating the discounted cash flow rate of return on new projects or the net present value for ongoing projects. These estimators of profitability are calculated using the following well-known equation: [ ] where i is the year, n is the total number of years, A, is the after tax net cash generation in year I, r is the discount rate and NPV is the net present value. In its simplest form, when the value of r makes the NPV equal to zero, the discounted cash flow-rate of return (DCF-ROR) is defined. The maximum economically recoverable reserve is identified at the point where the NPV or DCF-ROR is at a maximum. Depending on the measure used (DCF-ROR or discount rate) for calculating the NPV, the definition of recoverable reserve will be different for exactly the same deposit. Maximization of the measure of profitability and the economically recoverable reserves should not be separated from the mining method and sequence of exploiting the reserve. The surface mining methods may involve multiple-pass development of the resource, mining to the ultimate limit in one pass or a combination of the two methods with backfill. Multiple-pass development When planning a multiple-pass mining operation, it is important to determine the width of pit expansions that are appropriate for a specific situation. Production personnel typically want wide, open work areas where operations can be set up to run at peak efficiency. While this is understandable, the trade-off between highly efficient production operations and an overinvestment in stripping should be carefully weighed. As long as safety is not compromised, a few cents per bank cubic yard increase in operating cost due to lower productivity by working in more confined spaces may well be offset by a decrease in the overall short-term stripping requirements. A mini study on productivity and cost should help quantify this cost before deciding on minimum phasing requirements. The bigger challenge associated with establishing smaller work areas is securing operations and management buy-in to marginally lower productivity when reporting results. When cost reduction is the important management goal and everyone is focusing on unit costs, one sometimes loses sight of the goal of total cost management and, even more importantly, maximum profitability. The first pit should be defined by the first grouping of recoverable mineral that has the highest after-tax unit value and forms a feasible mining unit. The assumed mining of the first pit should be followed by the assumed mining of the second most profitable practical pit or pit expansion. If this process of grouping and sequencing is followed until the profitability approaches zero, the general sequence required to extract the maximum economically recoverable reserve is identified. The curve in Fig. 1 is constructed for a rate of production, R, and a quality management strategy, Q, by calculating the NPV for a series of sequences, with each sequence assuming that the operations are terminated on successively lower profit pits. These values are plotted to form the curve in Fig. 1. If the operation ceases on a pit that has too high of a profit, opportunity is lost, and the NPV is lower than the maximum. The NPV curve peaks and starts to decline before the zero-profit pit is assumed mined. This occurs because the money invested in advanced stripping would have made more money invested at the discount rate than by mining the next pit expansion. Therefore, the maximum economically recoverable reserve is defined by the pit limit corresponding to the maximum NPV. There may be an opportunity to refine the definition of the "ultimate pit" around the maximum-value point. The precise definition of the ultimate pit early in the mine life may or may not be important today, depending on how far off in the future these limits will be reached. By the time an operation must decide on its last increment of economically recoverable reserve. much of the

Jan 1, 2000

By A. W. Fahrenwald

The gyratory mill shown in Figures I and II is a ball mill in every sense of the term, in that the grinding media are balls. The media container, called the shell, is of the form of a shallow cylindrical tank whose position is with axis vertical The mechanism of the mill is designed to swing the shell in a circular path of small radius and, at the same time, to hold the shell in a position of constant orientation, i.e., the motion of the shell is such that every point on the shell surface -- bottom, wall and cover--travels in a perfect (horizontal) circle. The gyratory mill is definitely not a centrifugal ball mill. The balls do not, individually Qr in mass, travel in a circular path. Each ball, under heavy pressure from all directions, develops a sphere, or zone, of activity. Particles entering this sphere are crushed by impact. The gyratory ball mill, unlike the conventional tumbling mill, does not have, and is cursed by, a "critical speed". The speed of gyration, and in turn the power drawn by the mill--and ball potency--is limited only by the mechanical en- durance of the machine parts.

Jan 1, 1959

The introduction of nitro-carbo-nitrate (NCN) blasting agents has been one of the most significant innovations in the explosive industry in the last twenty years. The most commonly used blasting agent is a rather narrowly proportioned mixture by weight of 94% ammonium nitrate (AN) and 6% No. 2 diesel fuel oil (FO) that is generally designated as ANFO. Other formulations have been developed but none of these have been as extensively used as ANFO. The relative safety of the nitro-carbo-nitrate (NCN) blasting agents almost immediately suggested bulk loading techniques to obtain economies in materials handling. The first attempt at bulk handling was to pneumatically load boreholes with ANFO. When the initial experiments were made in 1957, it was apparent that there were three problem areas which needed study to minimize potential hazards. These were: 1. Static Electricity 2. Fumes 3. Safe Handling Procedures Since those early days, considerable work has been performed in evaluating these problem areas and in arriving at procedures and recommendations that would provide the required safety. Despite the relative insensitivity of ANFO type products, all normal practices for the safe handling of explosives should be obselved. Smoking should not be tolerated in the vicinity of blasting agents and misfires should be handled in the same manner as a misfire with a dynamite charge. The purpose of this Technical Report is to discuss the problems of static electricity and fumes and the solutions that have been developed. Safe handling procedures have been discussed by the Bureau of Mines and are specified by various state and local regulations. Since regulations vary from state to state, the local, applicable regulations must be followed within the area of their jurisdiction. General information is contained in a U. S. Bureau of Mines report, IC 8179, "Safety Recommendations for Sensitized Ammonium Nitrate Blasting Agents" (1963).

Jan 1, 1973

By L. T. Larson

Nothing in Turkey is simple. Its his¬tory is long and convoluted, its culture fascinating, its metallogeny diverse, and its geology very complex. This article will focus on the geology of western Anatolia and the precious metals poten¬tial of this third of Turkey. Any gold produced by mines in Tur¬key since the early 1900s has been a by-product of the mining for other met¬als, such as copper from the massive sulfide deposits of the Pontics. Archaeological records, however, prove that gold was mined from the Pactolus (present day Gediz) River and refined by Croesus at Sardis in about 550 BC. Other records and legends make it possible that gold was mined before 1200 BC for the Homeric City of Troy (Priams treasure?) about 25 km (15 miles) east of Canakkale at Mad¬endag and Kartaldag. A final legend of antiquity suggesting gold in what is now Turkey relates to King Midas. And, indeed, the city-state belonging to a king of that name has been recognized near the city of Eskise¬hir. More recently, precious metals have been mined at Madendag-Kartaldag in the late 1800s. Arapdag, near Izmir, remains the only "authenticated" epith¬ermal precious metal deposit in Turkey (Mosier et al., 1985). With this spotty record, why the sud¬den interest shown by at least five Euro¬pean-based, three or four US-based, and several other international mining firms and their Turkish subsidiaries? Like other aspects of Turkey, the complete answer is not simple but, reduced to its basics, has three parts. Turkey, relative to many developing nations, has a stable, democratic form of government (although it also has a for¬midable bureaucracy) whose currency exchange rate is premised on the US dollar. New laws promulgated since 1983 have opened the country and welcomed foreign investment. Some have even provided investment incentives. The Mining Law of August 1985 made sweeping reforms of the old land tenure system. This law made it possible for a foreign-based company to have a wholly-owned Turkish subsidiary en¬gaged in mining. Equally important is the belated recognition that western Anatolia, while geologically compli¬cated, is today basically a province Neogene extensional tectonics having many of the geologic attributes of the leading gold producing province of the US - the Basin and the Range. Geologic rationale for precious metals exploration Tectonic/lithologic framework: Alle¬gorically and simplistically, Anatolia during early Neogene (middle Miocene) can be likened to a tube of toothpaste with the cap off. It is squeezed in the vise formed by the Arabian plate mi¬grating north toward the southwest end of a stable Asian platform. The "tube" was compressed. It could not expand to the east because it was sealed by what is now southern Russia and Iran. The filling of the tube escaped to the west, in the direction in which the cap was miss¬ing (Fig. 1). So developed during the middle to late Miocene the western-most struc¬tural province of Anatolia. This was done by a process aptly termed tectonic "escape" by Sengor et al (1985). This province is dominated by exten¬sional tectonics much like the Basin and Range of the western US and has an estimated extension of between 30% and 50%. The most striking manifesta¬tion of this extension is the 10 to 11 major east-west trending grabens (Ge¬diz, Buyuk Mendares, Kocuk Mendares, etc.) and intervening horsts, although a much greater number of smaller, gener¬ally northeast-striking grabens and half

Jan 1, 1989

By Vincent R. Bovino

Introduction Only a person fresh from an information vacuum could not know the status of this nation's economy. The inability of the US to compete in the world marketplace is manifested in many industries, from shoes to computer chips, from cars to copper. What industry will next fall prey to world competition? Perhaps the question should be, what insustry will next fall prey to declining productivity? American industry is being forced into an era where the focus must be on productivity, quality, cost control, and competition in the world marketplace. It is approaching a change that could rival the American Industrial Revolution. The future of the US is bright only if it can increase productivity by trying different and new ways to manage its businesses and people. Unlike the easy successes during the 60s and 70s, success in the decades ahead will depend on an ability to compete in the world market. Any operation can achieve unlimited productivity by developing the resources within its employees. As an industry, mining has harvested the earth's resources. As an industry in trouble, it now has to learn to tap human resources to release the energy and creativity in each person. Recently, I worked with a mining operation to reopen a mine and implement a different management approach. The extensive changes resulted in a 50% reduction in cash cost of producing silver (from $0.40 to $0.19/g or from $12.50 to $6 per oz). Thus, an unprofitable mine became an attractive business venture without technological changes or significant capital infusion. The operation is union-free, in spite of being in a highly unionized area. The mine implemented a real productivity improvement process called "gain-sharing." Employees now recognize their individual success is tied to the success of the business. They recognize the day of the free lunch is over for mining employees. This paper will explore three areas related to productivity: • some of the unspoken "whys" of the mining industry's paralysis and how management has caused unproductiveness in mining operations; • major components of a productivity improvement process; and • characteristics common to companies with successful productivity plans. Unspoken whys When things go wrong, everyone tends to point a finger at someone, anyone. This industry has blamed every conceivable person, corporate group, government agency, foreign government, and private group for its failures. The fault finger will not work anymore. Nobody is listening. It is a characteristic of winners in management to assume responsibility for less than acceptable performance. Excellent people tend to blame others less for problems. Everyone involved in mining should shoulder part of the blame for the industry's illness. Is the problem low prices or our high operating costs? To regain our status in the world marketplace and increase our productivity, we need to painfully and honestly talk about our mistakes.

Jan 3, 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

By S. Polegeg

The basic principle of this separation method was already defined in the middle of the nineteenth century. However, a change over for the treatment of minerals has followed from the construction of proper machines i.e. airjigs and airtables as late as in the twenties and thirties of this century. The main application of this technology was subsequently found in coal processing and reached quite a great dimension in the two following decades. The number of applications of this method in mineral dressing plants decreased rapidly and has almost vanished in the fifties in favour of wet concentration procedures. It has been for a long period as long as up to the eighties that no more consideration was taken for applying dry gravity separation in the field of mineral processing also due to the successful introduction of flotation. Due to the fact that labour cost was increasing remarkably within the past period after the end of World War II also the economic conditions in the agricultural sector became more though. As a result there came up a great demand for harvesting machines. Since agricultural products can only be processed by dry methods in a prevailing number, highly developed machines were introduced for the dry processing of food and feed stuff.

Jan 1, 1992