Search Documents

By Todd S. Harris

Industrial minerals or non-metallic minerals are loosely used terms applied to a diverse assortment of materials which, in many cases, have nothing more in common other than the fact that they are neither metals nor fuel minerals. To help bring order to this otherwise random assortment of minerals, we have grouped these materials into two main categories; chemical and physical minerals, and nine sub-categories based on end-use applications as shown in Table 1. Chemical minerals are products which are principally used for the specific chemical elements they contain, whereas physical minerals are products which are used to meet specific performance specifications. The latter part of the 1970?s, in particular 1978, were considered peak years in terms of production and sales for many industries, By using 1978 as a base year, we can evaluate wherethese markets stand today after the recession of the early 1980's and the recovery which began several years ago. From this historical overview and appraisal of the current situation, various assumptions can be drawn as to which markets are expected to perform well into the 1990's.

Jan 1, 1987

By Grover H. Emrich

Pennsylvania,, due to its location in the humid east, is fortunate to possess within its borders large quantities of water. Most of the State is drained by three major river systems-the Ohio, Susquehanna and Delaware. This abundant supply of surface water has been widely utilized throughout the State, but today other sources of water must be developed due to the increasing demands for water, die largest undeveloped source of water in Pennsylvania is ground water. Pennsylvania is also fortunate to possess extensive coal resources. These coal resources have contributed measurably to the development and prosperity of the States Coal and water's - two valuable resources - have been necessary for the development and industrialization of Pennsylvania, The State needs both resources but can no longer afford to develop one while adversely affecting or destroying the other, We are aware of the effect of coal mining on surface water, but coal mining can also materially affect subsurface water, This effect will according' to the local geologic conditions.

Jan 1, 1965

By Y. C. Kim

An alternate development drilling strategy to the one currently in use at the nine was investigated using geostatistics for a portion of the pit. The study area consisted of 4,000' x 5,000' in plan and 1,080' in elevation. The massive orebody, the three-dimensional nature of the problem, and the location of ultimate pit limit in the study area all created some unique problems in devising the development drilling strategy, as compared to the two-dimensional tabular deposits such as coal deposits. Rather than using the confidence interval of the global reserve estimate as the main criterion for development drilling, the confidence interval of short and medium range mine planning blocks was used as the objective. Based on somewhat arbitrarily selected level of confidence, the results from this study showed that a total of 50 DDHs rather than the planned 62 DDHs is sufficient in the study area, if the selected confidence levels are acceptable to the management. This paper also emphasizes the importance of the particular objectives being used in development drilling and how they influence the "optimai" place- ment of the development drill holes.

Jan 1, 1981

By Fred T. Towne

There are a number of air classifiers manufactured throughout the United States and the rest of the world. The classifiers manufactured by Alpine, A. G. of Augsburg, Germany, are unique in their abilities. It is this uniqueness that I wish to delve into and in this respect we will limit this discussion primarily to the classifiers as manufactured by Alpine. It has been reported in the past that these classifiers were introduced into the. United States in the late 50's. Until the introduction of the Alpine Classifiers, air classification seldom produced a satisfactory fractionation of a product below 45 microns (325 mesh) or above approximately 22 mesh. It has been a common practice to classify fine materials which used water as a carrier medium The use of centrifuges are today producing thousands of tons of finely partitive powders in the very small particle size range. The use of centrifuges in connection with wet grinding mills has increased the rates of production of these mills considerably.

Jan 1, 1965

By H. R. Green

The design of slurry launders has usually been based on strictly empirical concepts. An examination of the most common procedures reveals that they do not account for many of the variables that are recognized as Significant for slurry transport. These may include flow rate, volume concentration of solids, solids specific gravity, solids size distribution particle shape, launder geometry, and roughness of the wetted surface. It was decided to develop a design procedure, which would accomplish two things: First: Take into consideration most of the known significant variables and systematize the procedure to assure consistent results. Second: Provide a rational basis for examining and utilizing operating data to refine and improve the system. To accomplish this, it was necessary to develop a basic design concept. This concept has been developed through a complex development history, and yet still appears workable and technically sound. That concept may be outlined as follows: First: The solids transport velocity is the fundamental basis for slurry launder design. Second: The stream configuration, hence the launder size, is integrated with the solids transport velocity so that the actual stream velocity exceeds the solids transport velocity. Third: The launder slope is that which will achieve the required actual stream velocity. It was originally planned to utilize a series of charts and nomographs for the design procedure. A nomograph, based on data given in Taggart's Handbook of Mineral Dressing (1), was developed to determine the solids transport velocity. The velocity thus determined was used with Manning charts to determine the launder slope .and configuration as though the fluid were water. It was planned to utilize a "slope adjustment factor" to increase the slope to compensate for the apparent viscosity of the slurry. All attempts to develop a suitable correction factor failed. This failure was principally due to the complex relationship of viscosity to the required slope. It was then decided to revise the entire approach. Specifically, the present procedure is based on the Darcy-Weisbach flow equation, which is rationally preferable to the Manning equation. The Camp (2) equation is used for the solids transport velocity. The necessity of reference to the Moody curves for the Darcy friction factor is avoided by using the Colebrook and White (3) equation. The resulting mathematics require iterative solutions for several of the unknowns.

Jan 1, 1978

By Ernest L. Bradley

A positive pressure ventilation system, augmented by a dewatering well curtain and underground longhole drilling, provides effective ventilation and radon control at EXXON Minerals Company's Highland Underground Mine in the Southern Powder River Basin of Wyoming. Testing different types of bulkheads, sealants, and bleeder systems has led to improvements in the basic ventilation system. Continued testing of new or different materials and equipment is expected to lead to further improvement in the ventilation program. Effective training of both miners and supervisors is essential to maintaining and improving ventilation techniques. This paper addresses the ongoing ventilation program and experience to date at the Highland Uranium Mine.

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 Jack Parker

Cycles of mine convergence coincide with annual cycles of temperature and humidity in the mine. Laboratory measurements confirm that the presence of moisture reduces rock strength and induces internal rock stress. Findings are used in the design of mine openings.

Jan 1, 1969

By S. K. Sahoo, S. K. Sharma, A. Yadav, B. Behera, G. S. P. Singh

A field representative modeling of the gob behavior is critical for the understanding of the associated mechanics of strata behavior in longwall workings. The findings of theoretical models and laboratory tests on the simulated gob material have shown the strain hardening behavior of the gob material. The double-yield material model, which is a built-in constitutive model in FLAC3D, has significant potential to simulate the gob compaction process as it represents materials which undergo irreversible compaction in addition to shear yielding. Apart from this, several researchers have attempted using modified elastic model or applied nodal force in reaction to the strain in the gob area as per the well-known theoretical relations to meet this requirement. Although these models can simulate the mechanical response of the gob for subcritical and critical extraction widths, they do not apply to supercritical extraction width as the gob stress may exceed the in situ stress level in such cases. For overcoming these limitations, a standard approach has been developed and validated in this paper, which can be used for simulating the gob behavior in supercritical longwall workings as well. The complete study is divided into two stages wherein the laboratory scale compression test on the simulated gob material has been numerically replicated to develop preliminary confidence followed by a parametric study of the double-yield constitutive parameters for a rational estimation of their values in different conditions. The calibrated model has been used for verifying its results by plane strain modeling of two different longwall workings, using well-established empirical and analytical findings and field observations. The approach suggested in this study can be used for the efficient modeling of the gob behavior of longwall panels under varying geo-mining conditions without compromising the accuracy of the numerical model. The meticulously validated model can be helpful in rational estimation of stress redistributions around the gob area apart from load transfer on the barrier pillar.

By S. K. Sahoo, S. K. Sharma, A. Yadav, B. Behera, G. S. P. Singh

A field representative modeling of the gob behavior is critical for the understanding of the associated mechanics of strata behavior in longwall workings. The findings of theoretical models and laboratory tests on the simulated gob material have shown the strain hardening behavior of the gob material. The double-yield material model, which is a built-in constitutive model in FLAC3D, has significant potential to simulate the gob compaction process as it represents materials which undergo irreversible compaction in addition to shear yielding. Apart from this, several researchers have attempted using modified elastic model or applied nodal force in reaction to the strain in the gob area as per the well-known theoretical relations to meet this requirement. Although these models can simulate the mechanical response of the gob for subcritical and critical extraction widths, they do not apply to supercritical extraction width as the gob stress may exceed the in situ stress level in such cases. For overcoming these limitations, a standard approach has been developed and validated in this paper, which can be used for simulating the gob behavior in supercritical longwall workings as well. The complete study is divided into two stages wherein the laboratory scale compression test on the simulated gob material has been numerically replicated to develop preliminary confidence followed by a parametric study of the double-yield constitutive parameters for a rational estimation of their values in different conditions. The calibrated model has been used for verifying its results by plane strain modeling of two different longwall workings, using well-established empirical and analytical findings and field observations. The approach suggested in this study can be used for the efficient modeling of the gob behavior of longwall panels under varying geo-mining conditions without compromising the accuracy of the numerical model. The meticulously validated model can be helpful in rational estimation of stress redistributions around the gob area apart from load transfer on the barrier pillar.

By Melvin W. Dadd

[One of the major problems in the purchase and sale of coal shipped in lake or ocean going vessels has always been the difficulty in obtaining a true analysis of the shipped coal?s quality because of faulty sampling by manual methods. As long as coal was sampled according to standards set up by ASTM methods designated D 492-48 there generally were no quarrels with the results obtained. However, due to varied weather conditions and because of the large number of cars sampled, there is no assurance that prescribed manual methods of sampling will always be followed. Because of this problem, the organization previously called American Coal Sales Association, now part of the National Coal Association, set up a committee compose of representatives from coal producers, coal shippers and coal consumers to study this sampling problem and to devise, if possible, a means of sampling on the high lift dumpers which could be automated so that a; true sample of the coal as loaded in the railroad car could be obtained.]

Jan 1, 1962

By B. J. Scheiner

A ferrous chloride-oxygen leaching system was investigated by the Federal Bureau of Mines as a means of re-covering copper and silver from a sulfide concentrate that had been pretreated to remove a majority of the antimony. The pretreated concentrate contained Cu, Ag, Pb, Zn, Sb, and As. Parameters affecting metal extraction, such as temperature, pressure, amount of ferrous chloride, and initial hydrogen ion concentration, were studied. Copper extraction of 98 pct was achieved by leaching 4 hours at 40 pounds per?square inch gage (psig) and 1000 ?C. Copper was recovered from leach solutions by cementation with iron, and the resulting ferrous chloride was recycled. Leaching the residue with cyanide followed by electrowinning recovered 99.7 pct of the silver. Iron, Sb, As, Pb, and S reported to the tails.

Jan 1, 1978

By F. J. Chernosky

In the past, a number of papers have been written on the use of various reagents as coal flotation frothers. For the most part, these papers have attempted to correlate the intrinsic chemical and physical properties of the reagents or reagent groups to the floatability of various fine coals. Because of the type or nature of evaluations made, chemically pure reagents were normally used. Generally, these reagents are unavailable in commercial quantities. Therefore, the results obtained with these reagents were usually limited in usefulness to the plant operator or metallurgist. This paper presents the results of a study in which commercially available forms of various reagents were used as flotation frothers. Flotation procedures which would conform in general to those employed in a large number of commercial coal flotation plants were utilized. The objective of the test was to compare these reagents on yield-selectivity-cost basis, that is, (1) the yields obtained, (2) the ash levels obtained, and (3) the reagent cost relating to these results.

Jan 1, 1962

By Majid Sadeghi, Ali Naghi Dehghan, Kaveh Ahangari, Seyed Mahdi Pourhashemi

"Instrumentation and monitoring of ground deformations in tunneling is a principal means for selecting and controlling the excavation and support methods among those foreseen in the design, for ensuring safety during tunnel construction (including personnel safety inside the tunnel and safety of structures located at ground surface) and, finally, for ensuring construction quality management. In this paper, the effect of Hakim Tunnel excavation on the behavior of the surrounding ground was investigated based on the geotechnical instrumentation. This tunnel with 1080 m length, 18 m width and 12.6 m height is being constructed using the SEM/NATM along the Hakim Highway in Tehran. The results which are obtained from recorded displacements by geodetic pins (on the tunnel wall and roof), extensometers and settlements pins (at the ground surface) demonstrate the tunnel stability during the various stages of excavation. However, it is concluded that the rate of excavation in different sequences could have a major role on stability of tunnel. In this case the surface and underground openings were monitored as well as needed for controlling the face probably collapse. INTRODUCTION Tunneling is increasingly being used world-wide to provide the infrastructure required for sustainable urban areas. The high demand for space and the disturbance of existing infrastructures by construction measures increasingly forces future infrastructure projects to be conducted underground. One of the important purposes of tunneling projects in urban area is not only to minimize displacements but also to control them during the construction (Pourhashemi et al., 2015). Normal method of tunnel stability analysis is not able to evaluate the real rock and soil mass behavior. Hence, instrumentation is a practical method to monitor displacements, to evaluate the stability of underground openings, and also to determine the rock and soil mass properties (Dehghan et al., 2012. Dehghan, 2013). Rocks and soils are materials with properties that can change instantly and significantly from one point to the next. Some complications may often happen due to uncertainties in the loads that the new facility must withstand during construction and operation. Instrumentation and monitoring provide quantitative information on actual behavior of ground and adjacent structures. A lot of deformation monitoring studies for determining and analyzing different kinds of engineering structures such as tunnels, bridges, high-rise buildings and dams are implemented. Considering the type of the structure, its environmental"

Jan 1, 2016

By Wayne P. Myers

Electricity, as normally thought of by a layman's definition, is a man- made force that has no color, no odor, is not visible, cannot be heard, yet man can control it and make it perform his work for him. A person dare not cheat on it, for it then will master him. It has laws, rules, and regulations that must be strictly adhered to if it is to perform in the safest, most reliable, and economical manner. In the early days of coal mining the power source was man himself. Later man employed steam and compressed air to reduce his muscle power requirements needed in the extraction of coal. By the turn of the 20th century, electricity had become the most common source of power for the coal industry. Steam and compressed air are still found in use in isolated cases today for specific applications; however, they are rapidly being replaced by electricity. Electrical laws and regulations are quite extensive and somewhat complex for the proper generation and use of electricity. Man-made laws, rules, and regulations for the care and handling of electricity, designed for man's safety, are rigidly enforced by Mine Safety and Health Ad- ministration (MSHA), as well as the various state departments of mines.

Jan 1, 1981

Computerized financial models can be used in all phases of the mineral industry from setting exploration targets to projecting profit plans for producing mines. In this presentation, I will use the example of an exploration company entering a new district to trace the application of financial models through the following intermediate phases. 1. Hypothetical analysis and strategy 2. First encounter of mineralization 3. Preliminary drill results - decision process 4. Feasibility studies 5. Post-feasibility negotiations 6. Producing mine 7. Acquisition of producing mines or mineral properties. I will conclude with a brief discussion of the mechanics of the financial models that we use at Wright Engineers Limited. As we progress through the seven phases, the availability and accuracy of the data will parallel the complexity and application of the financial models. However, the same basic financial models are utilized throughout the seven phases. I will begin by suggesting that the exploration group is somewhat autonomous and has the mandate to explore in Western Canada.

Jan 1, 1979

By Paul F. Thiele

The mining industry of Georgia, while not as large as in some other states, is still an important part of the economy. Total value of mineral production in 1966 was $148.6 million.l/ Clays and stone produced the most income, Other minerals included sand and gravel, iron ore, mica, talc, barite, bauxite, cement, feldspar, kyanite, peat, and rare-earth metals, titanium and zircon concentrates. Georgia ranks first among the states in production of kaolin, second in fuller's earth and rare-earth concentrates, third in bauxite and kyanite, fourth in barite and ilmenite, and fifth in feldspar. It is quite likely that phosphates will one day be mined in the south eastern part: of the state, and that alumina will be produced from the extensive kaolin deposits in the central part of the state.

Jan 1, 1968

By Richard C. Enochs

In order to clearly understand our process control system it is necessary to briefly discuss the various process control systems that were considered and why we chose our particular configuration. We considered Analog Systems, Computer Supervisory Systems, Computer Setpoint Systems, Direct Digital Systems and Direct Digital with Backup Systems. Our concept of these systems is illustrated in Figure 1 through Figure 5. We chose Direct Digital Control with Manual Backup because it had the greatest flexibility, ease of implementation and cost no more than a pure Analog Control System for one control concept. There would be no increase for a Direct Digital Control with Manual Backup System if the control concept were changed, while there could be considerable additional cost with an Analog System, if the control concept were changed.

Jan 1, 1975

By A. Tobey Yu

The smelter is the heart of a copper producing operation. Its principal function is to reduce and convert raw copper concentrates and/or leach plant precipitates into blister copper before it is refined. In addition to concentrates and precipitates, typical feed to a smelter also encompasses matte chips, flue dust, flux and lime. By nature, the characteristics of these materials are extremely variable, ranging from sub-micron to lumps, from slurry to dust, from abrasive to corrosive and free-flowing to adhesive. Furthermore, as a result of geological formation, most of the world's open pit copper mines are located in a semi-arid zone, where precipitation is minimal. This particular climate compounds the problem of handling these materials.

Jan 1, 1976

By Gregory E. Korbin

The effectiveness of pre-reinforcement as an immediate stabilization measure as well as its contribution to the permanent stabilization of a tunnel were studied through the use of physical (Figure 1) and numerical models (1). Physical models were designed for the investigation of two pre-reinforcement systems: first, reinforcing far ahead of the main excavation (Figure 2); second, spiling reinforcement ahead of the face (Figure 3). In both cases, the use of reinforcement was responsible for permanently stabilizing an otherwise unstable opening. Data from the physical models were used to calibrate a numerical model from which additional information on long term behavior, methods to account for the capacity of a pre-reinforcement system, and the mechanisms involved were ascertained. These studies indicated that pre-reinforcement can stabilize a rock mass effectively as it reduces deformations and thereby deterioration due to strain softening, provides rock mass confinement leading to increased available strength, and maintains rock arch continuity allowing for increased tangential stress in the immediate vicinity of the opening. Field studies verified the capacity of spiling reinforcement to restrain initial deformations.

Jan 1, 1976