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By A. Torrance, M. G. Seo

Velocity of detonation (VOD) is an important variable when evaluating the performance of mine blasts. Typically, for a VOD measurement, individual probes have to be loaded into each blast hole that requires a measurement, which increases the loading time and is not representative of the whole blast. Experimental studies of electromagnetic pulse (EMP) from the detonation of explosive charges show that electric and magnetic field signals are observed when chemical explosions occur in the air, at the ground surface, and in the underground. EMP has the potential to evaluate VOD of the whole blast without impeding the loading process. Due to a variety of physical causes which make the electromagnetic effects complex, measuring EMP of the detonation of explosive charges has not been fully studied yet. Five different antennae were tested with explosives, which are commonly used in mining industry. Among the five antennae, aluminum and copper tape, and wire were successful to detect the EMP. INTRODUCTION The measurement of the velocity of detonation (VOD) helps in evaluating and comparing relative performance of explosives in mine blasts. A VOD of an explosive is usually predicted by empirical mathematical equations or measured in-hole by VOD meters. However, conventional methods to measure a VOD have constraints: only a limited number of holes can be measured because cost of consumables for such systems is very high, and systems only allow a certain number of holes to be measured. The measurement cables have to be placed into the holes prior to loading with explosives which means that preparing to take the measurement is time consuming and has to be well coordinated with the mine. In order to evaluate VOD for a whole blast, there is a possibility of using electromagnetic pulse (EMP) from the detonation of the explosives. As there are many parameters that affect the generated EMP from explosive charges, measuring EMP of the detonation of explosive charges has not been fully studied yet. Most studies conducted relate to military related explosives, not the ones frequently used in mining industry. This research has been performed to have a better understanding of EMP from the types of explosives which are commonly used in the mining industry. To discover a way to detect EMP efficiently, five different types of antennae have been studied in the air and in the underground blasting conditions: coil, monopole rod, log periodic, wire, and aluminum and copper tape. LITERATURE REVIEW Conventional methods of measuring VOD Over the years, demands for more accurate theoretical predictions and physical measurements of the effects of the explosives have increased. Especially when both demand and commodity price decline, mining companies are keen to understand the effectiveness of explosives since it has a direct relationship with fragmentation, which influences their production rate. Since the 1940s, various methods have been devised to determine VOD of explosives.

Jan 1, 2019

By R. L. Clayton

The Bagdad district is 67 kilometers west of Prescott, Arizona, (Figure 1). The area north of the Old Dick and Bruce Mines was originally mapped by Anderson, Scholz and Strobell between 1943 and 1945, (1). The region is perhaps better known for the Bagdad porphyry copper deposit of tertiary age. However, 2 to 5 kilometers south of this deposit are several small massive sulfide occurrences in a eugeosynclinal Precambrian greenschist environment. More specifically, in. the Bridle formation of the Yavapai schist series. Three of these mines - Old Dick, Bruce and Copper Queen - were mined by Cyprus Mines Corporation between 1957 and 1977, and produced nearly 2mm tons of 3.6% copper and 12% zinc. These deposits occur at the interface between andesite and rhyolite and are stratiform in character. Certain structural and textural properties of the Bruce orebody suggest that remobilization of the massive sulfides occurred at some period during the metamorphic history of the area.

Jan 1, 1978

By R. J. Miller

The current National commitment to expanding the human presence into the solar system will clearly require major facilities in Earth orbit or possibly on the moon. Such facilities will need large amounts of materials for structural modules, life support, propulsion, and shielding. The heavy transportation costs in fuel required to lift materials from the Earth's surface make a terrestrial-based space system inherently inefficient. A more cost-effective approach would be to provide as much of the required materials as possible from other bodies in space not having the high cost of Earth launch. This paper identifies potential targets for space-based resource utilization, constraints on exploitation, and relative benefits of various sources.

Jan 1, 1992

By B. C. Paul, R. Q. Honaker, M. Huang

Froth flotation is now, the most commonly used method for cleaning fine-coal fractions in coal-preparation plants. Past research and industrial practice have demonstrated that froth flotation achieves excellent separation efficiencies for fine coals having only a small fraction of middling particles. However, the efficiency of froth flotation decreases sharply as the concentration of middling particles increases. This is due to the flotation of high-ash particles that have a small amount of hydrophobic coal present at the surface. Because gravity-based processes are much more efficient for the treatment of middlings, the application of centrifugal washing for fine-coal cleaning was studied with an emphasis on the primary cleaning of fine-circuit feed. Results are shown of a parametric study that used a semibatch Falcon centrifugal concentrator. The results of the study revealed that separation performance is a function of particle size, bowl geometry, feed solids content and feed rate.

Jan 1, 1996

By Gregg J. Hodges

The Stillwater Mining Company, a partnership of The Pittsburg & Midway Coal Mining Co. and Manville Corporation, began commercial production of flotation concentrates from the western hemispheres' only primary platinum palladium deposit at Nye, Montana in March 1937. In the fall of 1987 an integrated pilot plant testing campaign of electric furnace smelling and oxygen? blown converting confirmed the feasibility of further upgrading to semi? refined matte or 'white metal". In the summer of 1990 the production smelter was brought on-line at Columbus, Montana. This paper describes the technology transfer from the pilot to the production smelter. Emphasis is placed on flowsheet development and the scale factors between the test and production furnaces and gas cleaning plants. The metallurgical results of the pilot plant and of the early months of production of the commercial works are also compared.

Jan 1, 1991

By R. W. Lake

The decision to develop an ore body can lead to multi-million dollar profits, or equally substantial losses. Accordingly, the effort required to adapt a valuation model to the specific proposal at hand, or even the development of a new model from basic principles, is clearly warranted. In the formulation of a model of this nature, one is faced with some major questions. For example, with the long term obligations that it implies, on what basis should a decision to initiate mining operations be made? Furthermore, how can the vagaries of inflation and the uncertainties that shroud the future be accommodated? Beyond the general principles by which mineral deposits are evaluated, specific cost behaviour is a function of the geology of the deposit, and of the mine design. Moreover, mine design, during the life of the mine, must be a continuing process somewhat akin to dynamic programming. An initial, apparently optimal, design is selected and mining commences. With production, a continual process of information updating leads to revisions. Thus if the maximum value is to be obtained, the mine design must be adjusted to conform to the changed conditions.

Jan 1, 1977

By A. E. J. Gallagher

There are many influences which have a bearing on the economics of industrial minerals production. The purpose of this paper is to discuss briefly three factors which have economic significance in the production of these mineral commodities. The three items of discussion include 1) the nature and relative value of the industrial minerals group, 2) project planning, and 3) market analyses. General aspects of these factors are familiar to most of us. However, an attempt will be made to give some current details regarding each. Also, in reality, project planning and market studies are usually so closely associated that they will be discussed jointly, rather than separately. This will be done by way of examples which show how these two activities actually evolved for two industrial minerals projects.

Jan 1, 1984

By F. J. Susko

The Bureau of Mines investigated rapid bubble-pulp separation to improve flotation kinetics. A shallow-depth froth separator was employed to quickly recover the mineral-laden bubbles from a mixture of ore, water, and air bubbles. The shallow depth minimized the rising distance required to recover even the smallest size bubbles (100 ~m). Therefore, the slurry remained in the unit only long enough to recover the bubbles before the pulp exited through the conical bottom. Joining this unit with a rapid bubble-particle attachment unit, a rapid flotation system was formed that floated silica from phosphate in one-fifth of the retention time for conventional mechanical cells. The hydrodynamics of the rapid flotation system along with fundamental parameters for scale-up are presented in this paper.

Jan 1, 1992

By A. D. S. Gillies, Hsin Wei Wu

An evaluation of the use of air cooling power as an index of the thermal environment is discussed. A body temperature prediction -. model based on body temperature tests, a concept linked to a maximum safe body temperature and the predicted fourth hour body temperature which depends on the rate of heat accumulation (heat storage) within the body has been developed and tested. This has led to the conceptual development of a personal response heat stress meter calibrated to the physiology of the personnel within the workplace. The proposed heat stress meter will be able to measure workplace environmental parameters such as air temperature, humidity and air velocity and the user can either select or manually enter other heat stress parameters such as work rate, clothing type and subject's personal response to heat. With a built-in computer program, the meter will calculate the ACP of the workplace, the fourth hour body core temperature expected and the maximum safe working time allowed for a pre- defined limiting body temperature. A brief description of the work required for developing the meter is included. The potential benefits of such instrument to the mining industry are also evaluated.

Jan 1, 1997

By Norman E. Lehman

INTRODUCTION The Washington Camp - Duquesne mining district is located on the east flank of the Patagonia Mountains, 98 kilometers south of Tucson and within 5 kilometers of the International border (Figure 1). Since the development of high-grade silver and copper ores by settlers in 1862, the Washington Camp - Duquesne district has yielded an estimated 450,000 metric tons of ore. The mined ores averaged 8% zinc, 2% copper, 3% lead and 124 grams of silver. REGIONAL GEOLOGY The Patagonia batholith, of Laramide age, crops out in the core of the Patagonia Mountains intruding Precambrian granite, Paleozoic sediments and Mesozoic igneous, volcanic and clastic rocks. This granodioritic batholith lies in a northwest-trending zone of Laramide plutonic rocks, which can be traced for a distance of 320 kilometers from the Nacozari district in Sonora, Mexico to the Silver Bell Mountains west of Tucson, Arizona. Several major porphyry copper systems occur within this plutonic belt including the Red Mountain deposit found at the northern end of the Patagonia Mountains. Data from more than 80 mineral deposits within the Patagonia Mountains show metal zoning symmetrical to the Patagonia granodiorite (Graybeal, 1975). Disseminated copper-molybdenum deposits occur within the batholith. Pyrometa-somatic, limestone replacement and vein deposits of copper, lead, zinc and silver occur in the wallrocks adjacent to the. granodiorite and epithermal manganese-silver deposits occur at the outer periphery of economic mineralization. GEOLOGY OF THE WASHINGTON CAMP - DUQUESNE DISTRICT Stratigraphy Nearly 900 meters of miogeosynclinal Permian and Pennsylvanian sediments are exposed in the district (Figure 2). In addition, 700 meters of older Paleozoic rocks crop out 6 kilometers north of the district. The Paleozoic rocks occur in fault contact with a sequence of Triassic-Jurassic pyroclastic and flow rocks, ranging in composition from latite to rhyolite.

Jan 1, 1977

By Michael L. Maniocha

Most magnesia (MgO), whether of natural or synthetic origin, is used in the dead-burned or periclase form as refractory linings for the production of steel. Continued research in refractory science, combined with good refractory maintenance and improvements in steel-making processes, have resulted in decreased use of magnesia. To make up for this loss of business, producers of synthetic magnesia have started to manufacture a variety of magnesium-based chemicals that are used in many industries. There are three primary methods of producing MgO. The first involves the calcination of naturally occurring minerals species. Most of the magnesia produced by this method uses the rhombohedra1 carbonate mineral magnesite, MgCO,. To a lesser extent, the mineral brucite, Mg(OH), is calcined to magnesia. Magnesia produced by the calcination of minerals is called natural magnesia. The second production method uses magnesium-rich brines, or sea water reacting with lime or calcined dolomite to produce magnesium hydroxide. The magnesium hydroxide is subsequently calcined to magnesia. Material produced in this way is called synthetic magnesia. The third major method of production uses saline lake brines to produce magnesium chloride. Magnesium chloride brine is sprayed into a reactor where it thermally decomposes into MgO and HCl. The magnesia is purified by slaking to magnesium hydroxide followed by calcination. Magnesia produced in this manner is also know as synthetic magnesia (Duncan and McKracken, 1994). The degree to which the magnesium minerals or the synthetically prepared magnesium hydroxide is calcined governs the physical properties of the resulting MgO. It is the physical properties that dictate the end use for the product. The terms used to describe magnesia vary along with the degree of calcination. Table 1 summarizes the terminology used when discussing the various forms of magnesium oxide.

Jan 1, 1997

The last decade has seen the use of powerful computerized Mine-Wide Monitoring (MWM) systems for detecting hazardous conditions in underground coal mines. Recently, the U.S. Bureau of Mines and Jim Walter Resources, Inc. (JWR) expanded the scope of MWM system to include ground control. Single-point extensometers were installed in each of 30 intersections along a tailgate entry. These instruments monitored the rate of roof sag, a sensitive indicator of roof instability. Data were collected by the mine's own computerized MWM system. The paper describes the successful integration of ground control instruments into MWM, the data reduction procedures, and the identification of several hazardous areas.

Jan 1, 1994

By P. Eng. Daniel Kelly

INTRODUCTION The Astoria property is located in the prolifically mineralized Abitibi greenstone belt and is one of the most advanced projects presently under development by Yorbeau Resources Inc. This property, which hosts the Astoria gold deposit, is located in the southern part of Rouyn township, Abitibi area, Quebec, 4 km south of the city of Rouyn-Noranda (Figure 1). The Astoria deposit has been the subject of underground development for over a half century, beginning with Granada Rouyn Mining Co. in the 1930's and followed by Astoria Rouyn Mines Ltd. in the 1940's. Yorbeau Resources Inc. acquired the property in 1984 and has, since then, conducted numerous exploration programs on this gold deposit. The diluted reserves of the Astoria deposit are estimated at 1,3 million metric tons grading 6,14 grams of gold per metric ton (1.4 million st at 0.18 oz/st). This reserve figure is based on the results of surface and underground exploration carried out from January 1986 to June 1987 and includes ore in the proven, probable and possible categories. This paper is divided into two sections. The first part includes a summary of the geological environment including a description of the gold bearing zones and a short discussion on wall rock alteration. The second part of this paper reviews the underground work and the objective of the ongoing exploration program.

Jan 1, 1988

By Robert J. M. Miller

Thank you Mr. Chairman. For more than 15 years a debate has been taking place among students of massive sulphide deposits as to the origin of these deposits. Prior that time it was widely accepted that the deposits were of hydrothermal, epigenetic and even replacement origin (Wilson, 14). Kinkel, Knight, Stanton and others advanced hypotheses which would explain the, formation of the deposits by different, largely syngenetic, volcanogeric processes. I was fortunate in having become involved in exploration for these deposits at about the time the debate was beginning and thus had an opportunity to apply with some success, some of the new and old ideas for formation of massive sulphide deposits. The deposits which I will discuss today are all located n northwestern Quebec, in the Abitibi orogenic belt. Mattagami Lake Mines is about 100 miles due south and Noranda's Horne Mine about 200 miles south of James Bay. In 1959 I prepared a talk which was presented to the 1960 CIM Convention calling attention to the spatial and possible genetic relationship between the ore sulphides of the Mattagami Area, Quebec and the tuffite, as well as the structures which controlled the ore. In this present paper I would like to cover the following points: (1) The general criteria used by the epigeneticists to support their contention that the deposits were formed after the enclosing rocks.

Jan 1, 1973

By Gerry Norton

The purpose of this paper is to make the most complete assessment of coal cleaning methods, both process and equipment related to modern-day production and environmental requirements. In order to achieve this primary objective, a number of interdependent aspects of coal cleaning technology require evaluation and analysis. 1.0 CLASSIFICATION OF SEPARATION PROCESSES Processes and cleaning equipment can be categorized according to the important parameters of 1) mechanics of separation, 2) size range application, 3) range or variance in accuracy of separation related to 2) above, and 4) feed-size ratio affecting 3) above.

Jan 1, 1977

By Lucien Duckstein

The purpose of this paper is to give recommendations for utilization of water resources in a mining region, considering also water supply and environment; the case study of mining for coal and bauxite under the karstic aquifer of the Transdanubian mountain of Hungary is used to illustrate the approach, which consists in formulating a static multiobjective control model and solving it by compromise programming. The three activities of regional mineral resource exploitation, water supply and environmental protection are represented by different objectives which cannot be expressed in commensuerable units. Thus, a solution which is optimal for one objective is usually far from being optimal with respect to the other two objectives. As a result, we are not seeking an optimal solution for the conjunctive regional system, but a good compromise, trade-off or "satisfactum" (1), (2).

Jan 1, 1979

By S. Nowosad, O. Langefeld, A. Godge

Pumped storage power plants are one of the options to store the fluctuating production of electric energy from renewable sources in a sustainable manner and is able to provide Europe with the opportunity to overcome the effects of climate change. However, due to the extensive land use required when planning the water reservoirs, several projects have been declined after social conflicts raised, even in Germany. Nonetheless, after the flooding and drought periods in northern Germany, the catastrophic floods of July 2021 in south west Germany, the country’s need to decrease its dependency on import of gas and energy supply, and the energy transition goals set for 2030 and 2050, it has become clear that the implementation for water reservoirs must increase in the coming years, whether above ground or underground. Furthermore, not only Germany is interested in the use of underground cavities for water and energy storage, other European countries as Sweden are currently developing studies and solutions to bring this concept soon to reality in Europe. This article introduces the systematic approach for planning and designing large underground cavities for water reservoirs as a sustainable energy transition approach and a climate change response by showcasing the process of selection and results of the “Energy and Water Storage Harz” (EWAZ) research project. Additionally, the results of the evaluation of the effect of implementing the selected underground and surface infrastructure into the current water management system in the region is presented. Finally, the different possibilities evaluated for the underground cavities within the project and the technical challenges involved are be discussed.

Feb 1, 2023

By J. A. Organiscak

This paper describes the research con-ducted on bit wear and respirable dust generation conducted by the US Bureau of Mines (USBM) and West Virginia University (WVU), a member of the Generic Technology Center on Respirable Dust. The USBM investigated wear, energy and dust characteristics of various conical bit designs when cutting rock. WVU studied the functional relationships between wear, cutting force, energy, and dust of one conical bit type when cutting coal. The objective of the USBM study was to identify qualitative bit selection guidelines for cut-ting rock; WVU's research objective was to determine optimum bit replacement guidelines. These research studies both found that bit geometry (a function of bit design and wear) influences energy consumption and dust generation. Bit selection and replacement recommendations are given.

Jan 1, 1995

The Bureau of Mines has studied 260 underground coal mine fires which occurred from 1970 through 1989. Every fire had the capacity to be hazardous to life and property, however upon closer examination some were found to be inherently more dangerous than others. Our research involved reviewing and recording specific information contained in published Mine Safety and Health Administration fire accident reports. The objective was to determine if degrees of hazard relative to fire source or location could be construed from information contained in the reports. We specifically looked at the propensity for fires to cause injuries and fatalities as well as the need to seal the area in order to extinguish the fire. Relative to all underground locations, this review found that fires occurring in main haulage-ways were most likely to cause injuries and fatalities as well as require sealing of at least the immediate area to extinguish.

Jan 1, 1993

By Jean-Luc Cornet

As modern conveyors are increasing in size and complexity, their control requirements are becoming more and more critical. In addition to the safety and equipment protection requirements, control systems are now called to implement intelligent drive controls derived from dynamic analysis modelling, as well as to provide fast and accurate diagnostics while keeping operator controls simple. These requirements led to the development of a new and innovative approach to control system development. This paper describes the control philosophy used by Conveyor Dynamics, Inc. (CDI) and some of the key features of our approach to the architecture of control systems.

Jan 1, 1993