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By Alvin W. Schillinger

Drilling was not entirely satisfactory in the search for native copper in the Osceola amygdaloid footwall as mining showed oreshoots to be more continuous than drilling indicated. The Geophysics Department of Michigan Technological University developed a portable induced polarization drill hole probe with a 3 electrode configuration and a sampling radius of 5'± A 20 ma current of alternately reversed polarity is pulsed at 3.5 sec. intervals and readings are taken every two feet. Potential is read during the "on" cycle for resistivity determinations. During the "off" cycle, after 10 ms delay, the I.P. potential is sampled for 10 ms and recorded. Resistivity (ohm-feet) and "S" values (mv/v) are plotted on semi-log paper. A lithologic log is plotted based on resistivity and anomalous "S" values noted. The low resistivity amygdaloid contains sills of high resistivity basaltic trap. Verified by core logs, amygdaloid-trap contacts could be picked to ±.5' from resistivity alone. Lithologic logs of long steel holes, based' on resistivity, now replaced sludge logging. An "S" value of 30 mv/v was established as the lower limit of diagnostic I.P. effects in mineralized amygdaloid and 50 mv/v as a threshold value for ore. Of 914 footwall zones drilled, 315 were probed yielding 203 anomalies. Success increased from 34% for drilling to 72% for drilling and probing. As checked by mining, 46 probe results were 78% correct. Failures were due to the instrument not detecting copper or to the misinterpretation of an anomaly. No false anomalies were found.

Jan 1, 1964

By J. M. Dean, R. L. Grayson

Introduction With the continued downward pressure on coal selling prices, mine management must make its operations as efficient as possible. The problem is the same one throughout the mineral industries, streamlining operations to maintain competitive min¬ing costs (Born, 1991). There has been a great deal of research into better using production manpower. But the story is different for operations support personnel. Traditionally, planning man¬power requirements are done annually, with modifications to the operating plan occurring generally quarterly. On the other hand, the demands on manpower are often dynamic, being responsive to changing productivity levels, mine conditions (including water influx, bad roof, poor floor) and unanticipated project requirements (responses to machine breakdowns or a new section setup requirement because of a drop in coal quality in another area). Such changes may impact the manpower structure significantly. At times they may cause serious labor relations problems concurrently. Realignments and the generation of instability in the workforce because of active job switching (bidding) are a result. Most responses by coal operators are reactive rather than proactive, a situation that could be mollified by more accu¬rate and detailed planning of predictable manpower require¬ments. A manpower planning tool is needed that takes into consideration such things as changing productivity levels and conditions as manhour requirements for different work areas are planned, rather than blindly allocated through traditional staffing modes. Mine Management Support System The Mine Management Support System (MMSS) is an integrated decision support system that was developed using Sun Microsystems hardware according to the contract be¬tween the US Bureau of Mines and West Virginia University. The software used in the development of MMSS included X¬ windows (Scheitler and Gettys, 1986) for the user interfaces, LASER (Raman, 1985; Hayhurst, 1990) for the expert sys¬tem and graphics components, and the C language for general programming requirements. Sun DOS was used to allow the use of IBM-compatible applications software on the Sun networks. Sun OS is the operating system. It can be viewed as an enhanced version of UNIX. One of the components of MMSS that was developed to address the many specific objectives outlined in Grayson et al. (1990) is the work scheduling system. MMSS accom¬plishes work scheduling by using a mathematical (goal) programming approach to minimize the amount of switching of workers from their regular jobs to perform other jobs (Grayson and Nutter, 1991). Manpower support program The main objective of MANSUPP is to plan a detailed manpower structure for a mine by incorporating a production schedule, condition-modified work standards and manage¬ment preferences to predict required manhours for various support activities, for example, belt moves. This is accom¬plished by gathering and processing planning information the same way a mine planner would. The program is menu¬driven with the selection of a particular menu item locating the user in the appropriate area within the spreadsheet to review/add information. All of the interactions between productivity, section conditions and management prefer¬ences and their effect on the amount of support work required must be considered. Information regarding the productivity of a particular section, the geometry of the section, work standards for individual activities and section conditions must all be gath¬ered for input into the program. In the initial stages of development, it was decided that the program be developed in an environment that mine planners were familiar with in order to accommodate the use of the program. Lotus 1-2-3 or a compatible (Quattro Pro) met this environmental need. Other reasons included ease of calculation due to built-in functions, powerful command language and macro capabili¬ties. Each of the major components of the program defined are summarized. Production schedule This area allows the user to input a production schedule for the entire mine over 12 periods. Space has been provided for five sections, advance or retreat, and two longwall sections. There are several calculations occurring in this area that do not apply to the determination of manpower, but serve as an aid in production planning. Section description The section description area of the spreadsheet is shown in Table 1. The first three items are calculated in the production schedule area of the worksheet and then transferred to this location. The remaining information is input by the user to be used in later calculations.

Jan 1, 1996

By T. L. Myron

In recent years increasing attention has been given to improving both the chemical and physical properties of sinter. The first step toward this goal was the production of a self-fluxing-sinter. More recently, blast-furnace operators have found that significant improvements in blast-furnace performance can be achieved by improving and controlling the physical size of the sinter. The results of full-scale blast-furnace tests have shown that blast-furnace production can be improved by using a closely sized agglomerate. The improvements obtained by the use of pellets, a closely sized agglomerate, are well known. In contrast, blast furnaces charged with sinter having a wide size spectrum have generally not yielded results as satisfactory as those from furnaces 1) * charged with pellets. Beginning in 1958, Appleby-Frodingham charged plus 3/8-inch sinter to their blast furnaces. Further tests by other companies in Canada, 2) the United States, 3) and Australia showed that blast-furnace production could be improved by about one percent when the plus 3/8-inch material in the burden was increased by one percent. Because of the promising results obtained with screened sinter, an extensive test program was initiated to determine an effective means of producing sized sinter in U. S. Steel's sinter plants. This paper describes the work done by the Applied Research Laboratory in this program.

Jan 1, 1965

By Steve Kral

"Gold rush" is usually associated the western United States - California, Nevada, and Colorado. The southeast section of the nation is known more for its rice, textiles, tobacco, indigo, and cotton. This area, though, is where it all began with gold in this country. The United States' first gold rush, in fact, is said to have started with the discovery of a 7.7-kg (17-1b) nugget in the Piedmont section of the Carolinas in 1799, some 50 years before the rush to California. The Carolina gold rush continued intermittently through 1942 when the Federal Government shut down all gold operations. Strong gold prices throughout the early part of this decade and new extractive technologies spurred a small resurgence of gold operations in South Carolina. Mind you, this is not Nevada with its flood of geologists and mining companies. Nor are there any 7.7 kg (17 lb) nuggets being discovered. But Ridgeway Mining Co., a joint venture between Kennecott Corp. and Galactic Resources, has set about mining 51 Mt (56 million st) of low-grade ore containing an estimated 43.5 t (1.4 million oz) of recoverable gold. The open pit, carbon-in-leach operation is located near the town of Ridgeway in South Carolina, about 32 km (20 miles) north of Columbia. Carolina gold North and east of Ridgeway, Piedmont Mining Co. operates the historic Haile gold mine near Kershaw, SC. And Brewer Mining Co. operates the nearby Brewer deposit. Between 1829 and 1942, South Carolina gold mines produced 10 t (318,800 oz) of gold. It all began in 1799 when Conrad Reed, son of a German immigrant farmer, found the 7.7 kg (17 lb) nugget in Little Meadow Creek, NC. His father thought the rock was worthless and used it as a doorstop, so the story goes. It took nearly three years before Conrad's father decided his doorstop was indeed gold. Gold was later discovered in the Greenville district of South Carolina. And, in 1828, Benjamin Haile discovered gold in a stream that ran through his property in Lancaster County, SC. Haile's mine became South Carolina's most famous and most productive gold mine, producing more than 7.8 t (250,000 oz). At first, miners worked the stream beds of Haile's property. Later, lode deposits were discovered on slopes alongside the creeks. They would lease 4.6 ml (50 sq ft) lots and mine as deep as 7.6 m (25 ft). During the Civil War, the Confeder-

Jan 1, 1989

By George K. Martin

This paper deals primarily with roof bolting in Kentucky coal mines from January 1, 1949, through December 31, 1954, a six year period. The Consolidation Coal Co? (Ky.), a division of the Pittsburgh Consolidation Coal Co., began systemmatic roof bolting in November 1948 in Mine #204, Elkhorn #3 Seam, at Jenkins, Kentucky, After the efficiency of roof bolting had been proven by the Consolidation Coal Co., this procedure was adopted by other companies throughout the state. In December 1954, approximately 46.4 percent of Kentucky's total production of coal from underground mines was obtained from roof-bolted areas. Statistics in this report will show the progress made in roof bolting during the six years, in addition to the roof bolting being done as of December 31, 1955. Significant progress has been made in the coal mines of Kentucky in reducing the roof-fall fatality, rates, during the past several years by adopting systemmatic roof bolting. The ground work by the Consolidation Coal Co, (Ky.) in cooperation with the Federal Bureau of Mines was based upon the previous experience of the St. Joseph Lead. Cc, in its Southeastern Missouri Mines and The Tennessee Coal and Iron Division of the United States Steel Corporation. The author gratefully acknowledges the cooperation and assistance given by officials of the various mining firms using roof bolts, the Kentucky Department of Mines and Minerals, and the Federal Bureau of Mines in furnishing photographs and information.

Jan 1, 1958

By Lee W. Saperstein

The SME Research Council assists SME and its constituencies in establishing research directions that will benefit the mining industry and its professions. It also provides information about these directions to its membership, to government and to related industrial societies. The 1995 Research Forum, organized and chaired by George Luxbacher, was the second in a series of meetings organized to develop these directions. A copy of the full proceedings is available from SME for $12 plus postage and handling. The first research forum (Saperstein, L., 1993, "Technology for the Future, MINING ENGINEERING, Vol. 45, No 11, November, pp. 1382-85) invited mining industry representatives to discuss the unsolved technical problems that were keeping the industry from greater economic and environmental efficiency. The second forum asked academic researchers to discuss the same general topics from their perspective. It came as no surprise that, in general, the two sets of presenters tackled the same problems. There was no surprise when the academics spoke of the need for fundamental long-term research. What may have been surprising was the number of university people who spoke for near-term research that leads to measurable economic returns or savings. The closure of the US Bureau of Mines (USBM) has changed the objectives and attitudes of the SME Research Council. From being a point of liaison between SME and USBM - a conduit of items from each party to the other the council is now much more on its own. This isolation presents opportunities and hazards. The opportunities are exciting because the council could be the focus for mineral industry research policy if it were properly structured. The hazard is obvious - if there is no bureau, it could be argued, why maintain the council? Many people believe that SME should take the first course and become the beacon for research policy. More than ever, money is being spent on minerals industry research by the federal and state governments - particularly at the mineral-oriented land-grant universities - by industry and by consortia among these groups. SME could be at the hub of these programs. There is a general concern that industry is less able to maintain an economic edge by means of geologic discovery. According to Titley, there will be fewer major, new world-class discoveries except, possibly, at the continental and tectonic-plate margins. Consequently, economic advantage will go to those companies and nations that stay ahead technologically. Given the inevitable diffusion of technology, it can be concluded that technology development, underpinned by research, must be continuous to maintain profits. This is a change from earlier years when change would occur in relatively rare major steps that were interspersed with extended periods of technological equilibrium. Over the fiscal years 1994 to 1997, there has been a 24% cut in research spending by the Department of the Interior (figures from the American Association for the Advancement of Science). This is the largest budgeted percentage cut in research funding of any federal department. Even so, there is still a substantial amount of federal research funding expended in the mineral and extractive-energy industries. The US Geological Survey, Environmental Protection Agency, Departments of Defense and Energy and others expend substantial funds on minerals industry research. Industry - producers and manufacturers - is also spending large sums on research and research-like activities. This activity argues that there is a role for SME's Research Council. Providing focus Consortia. The closure of USBM has resulted in the migration of expertise to consulting firms and to other entreprenrutisl research entities. Many of these groups are creating ad hoc consortia among themselves, nearby universities and industrial partners. The Research Council is well placed to provide an open forum for these con¬sortia. Presentations of research results, as went on in the annual meetings of the Generic Mineral Technology Centers, can help to establish an. archive of results and an avoidance of duplication of research. A continuing sense of research directions can evolve. National Science Foundation. No discussion of consortia would be complete without mention. of the National Science Foundation's (NSF) programs for Industry/University Cooperative Research Centers (IUCRC) and Grant Opportunities for Academic Liaison with Industry (GOALI). NSF is aware of the gap in federal support of science and technology caused by USBM's closure.

Jan 1, 1997

By K. F. Unrug

The research work reported in in this paper deals with the monitoring of roof behavior in a drift mine located in Eastern Kentucky operating in the Coalburg Seam. The thickness of the seam at the monitoring site ranges between 9 and 10 feet with the immediate roof changing from sandstone to shale then back to sandstone. Shale thickness varies between 0 and 2.5 feet. The characteristics of the immediate shaly roof were monitored with 38 dynamometers which were set up in three survey lines to cover the entire range of shale distribution. The dynamometers are capable of providing accurate load readings in the range of +/- 5 pounds. To closely observe the contribution of moisture toward roof deterioration the dynamometers were set up in intake and neutral airways. A television borescoping camera was used in conjunction with the dynamo- metric instrumentations at pre- determined observation holes to physically observe and record the separation process of the shale and sandstone stratum with respect to time. Monitoring took place between January 1985 through January 1986 in order to cover a full cycle of dry and wet mine conditions associated with the seasonal changes. Analysis of the data show a trend of roof deterioration induced by condensation and eventual penetration of moisture within the immediate roof bedding planes, leading to rapid disintegration of the mine roof.

Jan 1, 1986

By Randolph E. Scheffel

Mill design and project execution are very demanding and interactive processes requiring the dedication and cooperation of many parties. The development philosophy which lead to the successful completion of Ranchers Exploration and Development Corporation's Escalante silver mill is reviewed. The project spanned 25 months from initial feasibility studies to start-up with the major construction effort requiring only 4 months. Mill performance for the second and third months after start-up, as well as fiscal 1983, is compared against the design parameters. Capital and operating costs are also discussed.

Jan 1, 1983

By W. J. Atkinson, E. M. Anderson

FOREWORD This paper is based on the authors' experience gained in the environmental assessment of major uranium projects in the former Department of Science and the Environment and Department of Home Affairs and Environment of the Australian Government. The authors gratefully acknowledge assistance received from colleagues within the Department of Home Affairs and Environment in the preparation of this paper. Special thanks go to Mr K.E. Thompson of the Department's Environment Division for his valuable comments and criticism. The views expressed in the paper are those of the authors alone and not the Australian Government or Dames & Moore. INTRODUCTION Uranium has been mined in Australia since 1954. A number of small scale mining and milling operations were active in the Northern Territory, in South Australia and in Queensland in the late fifties and early sixties. However, in the late sixties there was an increase in exploration activities in the expectation of an upsurge in world demand for uranium Substantial new resources were delineated in the Northern Territory, Queensland, South Australia and Western Australia. The most significant deposits were located in the Northern Territory, in what is called the Alligator Rivers Region located approximately 200 km east of Darwin. The Region is in the latitude of 13° South and thus lies within the Australian tropics (Figure 1). It consists of approximately 2.3 million hectares of natural wilderness containing much spectacular and attractive scenery. The area is noted for its abundant wildlife, particularly the waterbirds that gather on the flood-plains. Much of the vegetation is diverse and interesting. The Aboriginal population still maintains elements of the traditional way of life, and the spectacular Arnhem Land escarpment contains many of the best surviving examples of Aboriginal rock art. Numerous rich archaeological sites provide evidence of continuous human habitation for tens of thousands of years. Climatically, the Region is of the tropical monsoon type with a dry season from may to September and a "wet" from November to March. High intensity short period rainfall is characteristic, and the average annual precipitation is in the order of 1 350 mm. The monthly mean temperature ranges from 25° to 30°C throughout the year. The development of regulatory controls on uranium mining in the Alligator Rivers Region has been affected by the political status of the Northern Territory. While Australia is a federation, established as an independent self-governing country in 1901, it was not until 1978 that the Northern Territory became to any real extent self-governing. Prior to 1978, the Territory was administered through a special department of the Commonwealth (ie. the Federal Government). Under the Northern Territory (Self Government) Act 1978, administrative powers similar to those possessed by the Governments of the six founding Australian states were provided to the Territory Government. However, the Commonwealth government did not transfer to the Territory all such powers and functions, and in particular there has been, since 1978, a dual role for the Commonwealth and Territory Governments in the regulation of uranium development. Details of this role are provided later in this paper. RANGER URANIUM INQUIRY By 1973, major deposits had been discovered in the Alligator Rivers Region at Nabarlek, Ranger, Koongarra and Jabiluka. The estimated reserves and mine life expectancy of these deposits are given in Table I. Other radioactive anomalies have also been identified in the area but, as yet, they have not been delineated or evaluated. [ ] In 1974, an agreement was signed between the Commonwealth Government and Peko Mines Limited and the Electrolytic Zinc Company of Australia Limited for the joint development of the Ranger deposit. In July 1975, the Government announced a Commission of Inquiry under the provisions of the Commonwealth Environment Protection (Impact of Proposals) Act 1974, into the proposed Ranger development. The inquiry was known as the Ranger Uranium Environmental Inquiry or more commonly, the Fox Inquiry after the presiding Commissioner, Mr Justice Fox.

Jan 1, 1981

By Justus B. Deen, Randy Peterson

INTRODUCTION The General Chemical Soda Ash Operation located near Green River, Wyoming produces about 4.5 Mt of trona per year. In July 1989, Mine Ventilation Services Inc. performed a ventilation survey of this complex trona mine which had thirteen active panels spread over 36 square kilometers. The ventilation survey and subsequent study showed that the intake shaft air velocities were at their practical limits (Wallace and Rogers, 1987). The need for additional intake capacity was immediate. The ventilation network modeling delineated the best location for this new intake shaft as it applied to the 5 year ventilation plan. Unfortunately, this location, 6.5 kilometers from the soda ash processing plant, would make heating this intake air very costly. Presently, the intake air is heated by heat exchangers which use waste heat from the plant. Air heating during the winter months is necessary for miner comfort and to prevent potential freezing of water lines in the mine. It was decided to examine the feasibility of heating the air geothermally by coursing it through an old production panel. This method of air heating has been used in this region with good results at the Stauffer Chemical Operation (now Rhone-Poulenc) (Moore, 1985). In 1990, a geothermal heating study examined four different production shaft/panel configurations and a workable design was found. The operators at the General Chemical Soda Ash Operations acted on this design and began raise boring a ventilation shaft in the Spring of 1991. This paper describes the ventilation system, briefly, and the geothermal heating studies performed. Findings of the 1990 geothermal studies are then compared to field data acquired in the Winter of 1992. THE VENTILATION SYSTEM The ventilation system at General Chemical had four shafts serving the mining horizon in July 1989; three of these shafts are located at the Northwest end of the mine. The active work areas had progressed to the South over the past years and supplying ventilation has become increasingly difficult. The 6.1 meter diameter #3 Production shaft and the men and materials compartment of the 6.1 meter diameter #2 Split Shaft had reached their air velocity limits. Conversely, the 4.6 meter diameter #5 Exhaust Shaft was under utilized. Ventilation studies showed the conversion of the 3.7 meter diameter #1 Exhaust Shaft to an intake would provide adequate intake capacity for two years. The next option to improve ventilation was the addition of an intake shaft at the southeast part of the mine at the intersection of H Mains South(H-M-S)and J Mains East(J-M-E) (See Figure 1). A service shaft has been planned for the extreme Southeast end in the late 1990's. Ventilation network analyses showed this interim intake shaft would have to be at least 2.5 meters in diameter to postpone the service shaft construction beyond 1995. The greater the size of the borehole, the further the construction could be postponed. In October 1991, General Chemical commissioned the 4.57 meter diameter #4 Ventilation Shaft near the junction of H-M-S and J-M-E as shown in Figure 1. The L95 panel would be used for air heating as described in the geothermal heating section to follow. GEOTHERMAL STUDIES Geothermal heating studies were performed by MVS Inc. in May 1990. Using a modified code of CLIMSIM, an underground mine climatic simulation model, several different shaft/panel configurations were examined to see which would provide adequate air heating during the winter months. CLIMSIM simulates heat flow into a single underground airway. The program was used to evaluate the heat flow to and from the airway surface and to calculate the resulting change in dry bulb temperature of the ventilating air. CLIMSIM uses inlet air conditions, airway characteristics, and rock thermal properties input by the user to predict the variation of psychrometric and thermodynamic parameters along an underground airway.

Jan 1, 1993

By D. A. Dahlstrom

Since the initiation of continuous vacuum filtration over a half a century ago, control of the performance of these units has been largely in the hands of the plant operators, Obviously there has been the introduction of variable speed drives, adjustable speed feed slurry agitation, vacuum control, etc. However, control of , filtration rate, cake moisture content, dissolved solids recovery by cake washing and dryness of solids where thermal drying is practiced is primarily up to the operators judgment and the settings he imposes on the controls he regulates, - filter cycle time, submergence, vacuum level, filter medium condition, wash water- rate, and other such factors. While this may seem to indicate that good operators are a paramount necessity, and certainly always desirable, a considerably more vital factor is a properly designed filter and filter station for the particular application. With improper design, highly skilled operator control will still leave much to be desired in the way of process performance. On the other hand, with correct design and application, the operator can easily and quickly control normal plant surges and quality variations within the flow sheet. Due to the growing complexity and inter dependency between the various processing steps in the modern flow sheet as well as the rising costs of capital investment, labor, maintenance, and losses involved with off quality product or insufficient recovery, automatic or inherent performance control of many of the unit operations within the metallurgical mill must be achieved. Continuous filtration should and can be susceptible to such control. However, as every instrument engineer knows, before control and automation can be achieved, a basic understanding of the operation is mandatory. This is primarily due to three factors. First, as in so many control applications, it may not be possible or feasible to measure the factor that it is desired to control. Thus, secondary variables that influence the major factor are substituted for control purposes. Secondly, it is always desirable to take advantage of any ?self-regulation? within the operation being performed on the equipment. In so doing, not only will automatic control be facilitated, but instrumentation is minimized while experiencing most efficient operation. Finally, automatic control is not a cure-all for improper process and equipment design and application. Hanging instruments on such an operation can be compared to constructing a sizable building on sand, Results will be disappointing.

Jan 1, 1960

By Kelly F. Bailey

Introduction On June 20, 1986, the Occupational Safety and Health Administration (OSHA) published revised asbestos exposure standards for general industry and construction. The standards reflect OSHA's attempt to adequately control workplace exposures to minerals it considers carcinogenic - minerals capable of causing or contributing to cancer. These standards specifically identify asbestos as: chrysotile, an asbestiform serpentine mineral; and the amphibole minerals amosite, crocidolite, tremolite asbestos, actinolite asbestos, and anthophyllite asbestos. Each of these has a more common nonasbestos mineral analog that exists in nature in a crystalline, blocky shape rather than the hair-like or fibrous shape of asbestos. The mineralogical names for three of these nonasbestos minerals are unique: antigorite for chrysotile, cummingtonite-grunerite for amosite, and riebeckite for crocidolite. The other three nonasbestos analogs do not have unique mineralogical names. They are simply designated as actinolite, tremolite, and anthophyllite without the word asbestos following their names. The 1986 OSHA standards not only cover exposure to the six asbestos minerals, they also cover specifically the nonasbestos forms of actinolite, tremolite, and anthophyllite (AT&A). The new standards regulate these minerals exactly like asbestos (OSHA, 1986). The construction aggregate industry views this as a major problem because these nonasbestos minerals are common amphibole rock-forming minerals in the earth's crust. They exist in small quantities over large areas of the United States (Kuryvial et al., 1974). These minerals, unlike asbestos, are not mined for a specific commercial purpose. They are unavoidable components in much of the aggregate used for construction throughout the US. They are also common in the gangue material of metallic ores. There are areas of the US where amphibole-bearing bed¬rock is common. Not every rock mass in these areas contain amphiboles, however. It does mean, though, that amphiboles are physically compatible with many of the rocks in those areas. And given the correct geochemical conditions, they will be present primarily in the nonasbestiform variety. In addition, these amphiboles will probably exist in the natural drainage system, sand and gravel deposits, stream sediments, lake shores, valley basins, or ordinary beach sand within these areas. There has been little quantification of nonasbestiform AT&A in dusts and soils in the US. This is not surprising since these nonasbestiform minerals are not commercially valuable. However, an example of the pervasive nature of these minerals can be found in a 1981 Geological Society of America publication where about 0.7% tremolite-actinolite was found in the desert dust in and around Tempe, AZ (Pewe, 1981). Since OSHA standards treat these common nonasbestos minerals as carcinogens in the same way as asbestos, large natural areas in the US are implicitly being labeled as hazardous by OSHA. When a substance is identified as a carcinogen, another OSHA standard comes into play, the Hazard Communication standard. There are also right-to-know laws in 9 states that essentially duplicate this federal standard. These standards require that a product containing 0.1% or more of an OSHA-designated carcinogen be labeled as such (OSHA, 1983). This means that much of the stone and sand gravel products occurring naturally and mined in the US could be labeled a carcinogen when, in fact, they are not. The National Stone Association (NSA) and the domestic construction and mining industries believe that OSHA has seriously erred. The NSA has studied the health, mineralogical, technical, economic, and legal basis for OSHA's action. These studies concluded that there is no justification for the agency regulating nonasbestos minerals as if they were asbestos. Health issues The preamble to OSHA's 1986 asbestos standard states that evidence for asbestos-like health effects from exposure to nonasbestiform varieties of AT&A is inconclusive (OSHA, 1986). The fact is, not only are the data inconclusive, they are nonexistent. During 1986-1987, NSA's occupational health and epidemiology consultant, Environmental Health Associates (EHA), reviewed all available health studies related to AT&A. EHA found evidence that malignancies in both experimental animals and humans are associated with the asbestos forms of these minerals. No experimental or epidemiological evidence was found that indicated such pathogenic effects occur from exposure to nonasbestiform varieties of these minerals. There are relatively few scientific studies of the health effects of exposure to nonasbestiform varieties of AT&A. In three different animal studies, exposure to either nonasbestiform tremolite or actinolite did not result in pulmonary fibrosis on in excess tu-

Jan 11, 1988

By Harry R. Dahlberg

Heap leaching is discussed as a unit process. Five factors are identified as the principal elements that can be measured and/or controlled. These are: 1. Material Size 2. Volume of solution 3. Tonnage of heap 4. Time 5. Solution concentretion. The Rate of Extraction Curves obtained from an actual heap or column tests describes the economic viability of the unit process. By analysis of these curves and the five factors end their inter-relationship it is possible to determine how the extraction rate can be increased. The practice of leach and rest used by many operators is analyzed and shown on a hypothetical rate of extraction curve. The influence of the driving force of the hydrogen ion and ferric Lon as Lixivants and its effect on the rate of extraction curve is discussed.

Jan 1, 1979

By A. W. Khair

This paper presents an analysis of respirabie dust generation due to the action of a continuous miner. Underground coal cutting by a drum-type continuous miner was simulated in the laboratory using a specially designed unique automated rotary coal cutting simulator (ARCCS). An analysis of -400 mesh particles was done on gravity collected material. Samples of entrained dust were collected through the use of cascade impactors. Both samples were analyzed for size distribution and particle shape. Using the simulated coal cutter permitted variation of operating and in-situ parameters to provide information on the effects on generation of -400 mesh particles. In these tests coal blocks with an approximate dimension of 18 in. x 15 in. x 6 in. (45.7 cm x 38.1 cm x 15.2 cm) were first subjected to confining pressures, equivalent to in-situ conditions. Such blocks were then cut by the cutting head of the ARCCS, thus simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-situ and operating parameters a number of other parameters such as 1) penetration of bit into coal, 2) penetration resistance (thrust and cutting pressures), 3) rotating velocity of cutting head, and 4) acoustic emission activity in the coal block were monitored. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted by using a sonic technique. At the end of each experiment the cutting paths of the bits in coal were photographed using an optical microscope with an attached camera.

Jan 1, 1985

By Edward J. Sterne

Several shale-hosted Pb-Zn-Ag deposits have been discovered in the northwestern Brooks Range, Alaska. Best known among these are the Red Dog, Drenchwater Creek, Lik, Ferric Creek, Hot Dog Creek, and Competition Creek deposits. They occur in a tectonically disturbed sequence of of Mississippian to Triassic shales, argillites, and cherts, and most are spatially associated with volcanic rocks. The sulfides are hosted in shales as disseminations, banded layers, massive lenses, and crosscutting veins. Detailed geologic descriptions of sulfide prospects in the Brooks Range were given by Tailleur (1970), Nokleberg and Winkler (1978), and Plahuta and Robinson (1979). Lange et al. (1980) discussed the formation of the deposits, the nature of the mineralizing solutions, and the temperature of formation on the basis of sulfur isotope studies. More recently, Harrover et al. (1982) detected a correlation between sulfide mineralization and high-temperature formation of charts associated with the sulfides by oxygen Isotope and chert crystallite size determinations.

Jan 1, 2013

A Directory of Computer Programs Applicable to US Mining Practices and Problems. A. L. Sanford, T. L. Myers, and J. F. Stiehr. USBM OFR 131-78, Nov. 1977. A Master Environmental Control and Mine System Design Simulator for Underground Coal Mining. Tape MDS-5. Pennsylvania State University. USBM CT 1.77, Dec. 1975. Contains computer programs on a dynamic general purpose computer simulation model for underground coal mining. A Method for Computing Stabilization Pressures for Excavations in Incompetent Rock. J. D. Dixon and M. A. Mahtab. USBM RI 8128, 1976. Describes technique for determining the confining pressures that must be provided for stabilizing underground openings in incompetent rock. Accident Cost Indicator Model to Estimate Costs to Industry and Society From Work-Related Injuries and Deaths in Underground Coal Mining. Vol. I.III. D. G. DiCanio, A. H. Nakata, D. Colvert, and E. G. LaVeque. OFR 39(1)(3)-77, Dec. 1976. Describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents In underground coal mines. An Interactive Computer System for Evaluating Coal Mine Illumination. R. Goldstein. USBM OFR 110-80, March 1980. Computer system for calculating the illumination on coal mine surfaces due to machine-mounted lights. Analytical Modeling of Mine Roof Behavior Using Statistical Material Properties. R. T. Langland and F. J. Tokarz. USBM UCRL-51876, Aug. 1975. Analytical study of coal mine roof behavior using a computer model of a room-and-pillar mining method. Application of a Total System Surface Mine Simulator to Coal Stripping. Vol. I-VII. Pennsylvania State University. USBM OFR 33(1)(7)-78, Aug. 1978. Describes model development, input and output documentation, three case studies of an open-pit materials handling simulator, and development of two equipment selection models and a cost model. Characterization of the Structural Behavior of Rock Masses. Vol. I-II. L. R. Herrmann and M. A. Taylor. USBM OFR 67(1X2)-75, Sept. 1974. Computer subroutines for characterization of rock behavior, Including variability of properties within the rock mass, planes of weakness orthotropy, strength criteria, and post-failure behavior. Coal Mine Electrical System Evaluation. Vol. I-VII, L. A. Morley, et al. USBM OFF! 61(1)(7)-78, 1977. A concept to improve underground coal mine electrical system safety and availability. This proposed technique is based upon the ability to predict incipient failures in the mine power system. Prediction is made possible by a new method which uses a minicomputer to implement pattern recognition algorithms. Computer Modeling of Fluid Flow During Production and Environmental Restoration Phases of In Situ Uranium Leaching. R. D. Schmidt. USBM RI 8479, 1980. Describes development and application of a computer model for simulating the hydrological activity associated with in situ leaching. Interpretation of Rock Mechanics Data, Vol. II (A Guide to Using UTAH2). W. G. Pariseau. USBM OFR 47(2)-80, June 1978. Brief description of a two-dimensional elastic-plastic finite element program intended for mine stability analysis. Iterative Approximation Techniques for Microseismic Source Location. G. H. Dechman and Meng-Cherng Sun. USBM RI 8254, 1977. Iterative approximation method for microseismic source location developed to adapt microseismic techniques for rock structure analysis to investigations of surface problems such as slope failure in an open-pit mine. Limits and Cost Sensitivity of Alternative Parting Handling Methods. Vol. I-II. T. E. Finch, D. R. Haley, and C. J. Speaks, Jr. USBM OFF! 117(1)(2)-77, March 1977. Programs to examine alternative methods of handling the parting between two coal seams in a surface mining operation. Alternative methods consist of equipment implementation in either a stowing or haulback technique. Methane-Water Flow in Coalbeds. H. S. Price. USBM CT 1-79, April 1972. This computer program calculates transient, two-dimensional, gas¬water flow in a porous medium. Plastic Canopy-A Computer Program for the Structural Analysis of Protective Canopies. K. D. Winters, G. A. Gavan, and J. C. Ault. USBM IC 8795, 1979. Presents a FORTRAN IV program for the structural analysis of protective canopies used In underground mines and rollover protective structures used in surface mines. The Three-Dimensional Structural Analysis of Double-Entry and Single-Entry Coal Mines. Vol. I-III. Agbabia Associates. USBM OFF 16(1)(3)-80, Oct. 1978. Describes the computer program designed to perform a three-dimensional finite element analysis of an instrumented section of double- and single-entry coal mines. Underground Mine Evacuation Plans Analyzed by Computers. D. Tesarik, D. Nicholson, and A. B. Boghani. MSHA, Vol. 4, No. 5, Oct. 1979. USBM has developed a computer program to evaluate and construct mine evacuation procedures and plans.

Jan 11, 1981

By Andrew P. Gize

A petrographic approach to studying the organic matter in ore deposits is advantageous in that direct observation of sample heterogeneity can be made, organic constituents (macerals) can be identified, and valuable information about the geological history of the sample (such as thermal history, oxidation, and reworking) can be obtained. Thermally immature bitumens are compositionally and structurally heterogeneous, and optically isotropic. The end product of thermal alteration, graphite, is compositionally and structurally homogeneous, and optically an isotropic. One route by which thermally immature bitumens can approach the graphite structure Is by an aromatic intermediate phase, termed mesophase. The development of optical anisotropy and a thermal mesophase has been observed In several high temperature deposits. Textures in bitumens are described from the thermally-altered Mississippi Valley-Type deposit at Nanisivik (Northwest Territories), the silver-vein deposit at Kongsberg (Norway), and the gold deposit at Carlin (Nevada). Textural evidence for multiple generations of bitumens, supportive of a pulsing model for incoming brines, is shown. Petrological evidence for the introduction of bitumens as an immiscible phase or possibly as micelles is shown in the Carlin and Kongsberg deposits.

Jan 1, 2013

By N. R. Hasenmueller, V. Rajaram, R. K. Leininger, D. D. Carr

The content of the paper by V. Rajaram does not fulfill the expectations of the title. But Rajaram submitted the article in October 1983, and he could not have foreseen the numerous developments that would occur before his paper was published more than two years later. Nevertheless, Rajaram failed to mention the interest in oil shale development in southern Indiana beginning in late 1979 and continuing through the present as a result of special financial encouragement of three oil shale projects in May and August 1984 by the Indiana Energy Development Board and the Indiana Corp. for Science and Technology. A session at the 1985 Eastern Oil Shale Symposium in Lexington, KY, Nov. 18-20, 1985, gave the current status of oil shale developments in the eastern United States. Speakers at this session reported on the three Indiana projects. First, Gary D. Aho, Cliffs Engineering Inc., spoke on a feasibility study by Cliffs Engineering and Allis Chalmers for a site-specific pilot plant using the Allis Chalmers process. The plant site is in Clark County, IN, on property of the Midwest Energy Resources Co. The project is funded by $240,908 each from the Indiana Energy Development Board/Corp, for Science and Technology (EDB/CST) and the US Department of Energy (DOE) and $120,454 from the corporate sponsors (total $602,270). Completion is scheduled for mid-1986. Next, Edwin M. Piper, Stone and Webster Engineering Corp., discussed the American Syn-Crude/Indiana Oil Shale Project. This effort followed the completion of two smaller projects funded by the Indiana EDB/ CST: "Testing of Indiana Oil Shale in a Petrosix Pilot Plant" (total funding by EDB/CST at $50,000) and "Assessment of the Petrosix Process for an Indiana Shale Oil Plant" (total funding by EDB/CST at $100,000). The status at the time of the report at the Oil Shale Symposium was that a request for an extension of time for securing nonfederal support had been submitted to the US Synfuels Corp. The proposal included building an 11-m (36-ft) diam retort in south-eastern Indiana to process the New Albany Shale and to produce 366 m3 (2300 bbl) of shale oil per day by the PETROSIX process. The Indiana EDB/CST had contracted with Stone and Webster at $401,100 from EDB/CST and $245,835 from Stone and Webster for activities to advance the project in the negotiations with Synfuels Corp. At the time of the report, this project was the only eastern oil shale proposal that was still on the agenda of the Synfuels Corp. As a result of Congressional action in late December 1985, federal support from the Synfuels Corp. is no longer possible. Finally, Victor H. Carr, Eastern Shale Research Corp., described his firm's project, which is jointly supported by DOE ($227,749) and the Indiana EDB/ CST ($73,850) and is entitled "Feasibility Study to Determine Suitability of an In-Situ Process to Recover Hydrocarbons from Eastern Shale." An area in Scott County, IN, had been chosen, but not a specific 9 x 15-m (30 x 50-ft) site. One burn of a small in situ retort is contemplated as part of the project. Besides these three projects, several reports on shale research were presented. Joseph Damukaitis, American Syn-Crude Corp., reported that a pilot plant using the hydrogenation-extraction (H-E) process (described at the 1984 Eastern Oil Shale Symposium) was 94% built and would go through shakedown with oil shale but would then shift mechanical devices to process coal mine waste. Current status of research on the HYTORT process was then presented by Raymond C. Rex, Jr. Oil shale beneficiation research at the University of Alabama/Minerals Research Institute was reported by R. Bruce Tippin. Scott D. Carter discussed continued research on fluidized-bed retorting of shale at the Kentucky Center for Energy Research Laboratory. Carl E. Roosmagi of DOE, Morgantown, reported on the oil shale research at the Morgantown Energy Technology Center (METC) laboratory. Henry J. Gomberg, Ann Arbor Nuclear Inc., discussed "Radiation Combined with Donor Solvents for Extraction and Up-Grading of Kerogen." Aurora M. Rubel and coauthor Eileen Davis presented results of research at the Kentucky Center for Energy Research Laboratory under the title "The Effect of Shale Particle Size on the Products from the Bench Scale Fixed Bed Steam Pyrolysis of Kentucky Sunbury Shale." Lastly, Maria Rockwell, Technical University of Nova Scotia, presented "Processing and Up-Grading of Low Grade Nova Scotia Oil Shale for Potential Use." A review of shale oil prospects by Gerald Parkinson in Chemical Engineering for Feb. 3, 1986, covers both western and eastern projects and includes a report that the US DOE is funding a few relatively small projects; most of the fiscal 1986 budget of $12 million for shale oil is for fundamental research. Projects include a $3.2 million three-year contract with Hycrude Corp. (Chicago) for development of the HYTORT process and a $1.2 million three-year contract with the University of Alabama's Mineral Resources Institute on beneficiation of eastern oil shale by froth flotation. The report incorrectly states that current projects include a total investment of $466 million in a pair of 18-month technical and economic feasibility studies for proposed projects in southern Indiana. The correct figure is $468,657 [$240,908 for the Cliffs Engineering/

Jan 1, 1987

By Roy M. Fleming, Christine B. New

The federal standard for limiting exposures to miners from radon daughters was reduced from 12 working level months (WLM) per year to 4 WLM per year in 1971. However, even at that time some researchers were concerned that the new limit would eventually be shown to result in an excess risk for lung cancer mortality in miners. The National Institute for Occupational Safety and Health (NIOSH) is now engaged in a comprehensive review of this topic. As the lead agency in this project, NIOSH has developed a work plan and established a work group to implement this plan. The procedure and specific considerations are outlined in the work plan for developing a comprehensive ionizing radiation standard recommendation for all miners, underground and surface. Such a recommendation will not only include estimates of health risks at various levels of exposure, but also appropriate recommendations for medical monitoring, sampling and analytical methods, sampling strategies, posting, engineering controls, personal protective equipment and recordkeeping. The work group has twenty-four members. Eleven members are NIOSH personnel representing six divisions of the Institute. The remaining thirteen members represent other federal agencies, specifically the Bureau of Mines of the Department of the Interior, the Mine Safety and Health Administration and the Occupational Safety and Health Administration of the Department of Labor, the Office of Radiation Protection of the Environmental Protection Agency, and the Bureau of Radiological Health of the Food and Drug Administration, Department of Health and Human Services. Several factors contributed to the decision to initiate this project. First, the efficacy of the current standard was considered. An initial study group was formed in the spring of 1980 by NIOSH to identify and evaluate articles that contained information on lung cancer mortality risks at and below the present permissible exposure limit. The conclusion drawn from their evaluation was that a two-fold excess risk of lung cancer mortality at and below 120 cumulative working level months (CWLM) of exposure to radon daughters is evident. This composite indication from selected studies was of sufficient magnitude to justify further evaluation. The study group, however, recognized that other studies and information must also be considered in a quantitative risk assessment which would form the basis for recommending an acceptable and feasible permissible exposure limit. A second factor in the decision to pursue further evaluation was the gaps in the current standard that had previously been identified by the Mine Safety and Health Administration (MSHA). These included lack of medical monitoring of underground miners and absence of regulations for surface miners. The seriousness of the health hazard relative to other hazards in mining was also considered. Along with exposures to silica and asbestos fibers, radiation was judged to be one of the major health hazards in mining, These combined factors constituted the justification to develop criteria and recommendations for improved mandatory health standards. The development process begins with a survey and review of the available world-wide information on the topic, including data and information developed by NIOSH. The end product of this review is to be a document that will contain an evaluation of the collected information and support for any recommendations that are made. To develop this document, the present work group has been divided into five task groups with the following emphases: Health Effects, Medical Aspects, Monitoring, Environmental Exposures, and Engineering Controls and Work Practices. The Health Effects task group is to evaluate the evidence from epidemiologic and animal studies of adverse health effects associated with all forms of ionizing radiation encountered in mining and milling operations. The "weight-of-evidence" of the results of all relevant and useful studies will be summarized, with the reasons for emphasizing the cited studies. The critical cells or tissues and the factors that should be considered in estimating the dose to these areas from various types of radiation will be identified. An evaluation will be made of the possible impacts of smoking and exposure to diesel exhaust on the determination of health effects related to radiation. The implications of biologically redundant dose in terms of the time between tumor initiation and death will also be analyzed. The Medical Aspects task group is to review the generally-accepted and the state-of-the-art medical technology for the detection of adverse health effects from ionizing radiation exposure. An evaluation will be made of the accuracy of urine and fecal analysis, wholebody counting, chromosome analysis and nose blows, as well as their usefulness for early detection of adverse health effects. Early detection is of little utility to the affected individual unless subsequent medical care can improve the prognosis. Recommendations for screening tests will be made after carefully considering the accuracy of the diagnostic procedures and the usefulness of early detection. Required recordkeeping and transfer rights will also be addressed. The Monitoring task group is to consider the state-of-the-art technology for the monitoring of occupational radiation exposures. Instrumentation, sampling strategies and analytical procedures will be reviewed for both personal and area sampling. The implications of the associated levels of confidence for non-compliance decisions will be evaluated. The discussion will also include an evaluation of the feasibility of replacing present monitoring systems with recent technology and the impact that a possible lower permissible exposure limit would have on monitoring requirements. The Environmental Exposure task group is to investigate the field procedures and mathematical methodologies which have been used to quantitate exposure levels to the various kinds of ionizing radiation. The magnitude and direction of the possible biases in past exposure assessments will be estimated. Specific attention will be given to the controversies concerning the quantification of the biological dose equivalent and the feasibility of recommending standards for mixed radiation exposures which use "rem" as the unit of measurement. The Engineering Controls and Work Practices task group will analyze the advantages and limitations of

Jan 1, 1981

By S. L. Bessinger

Introduction In the design and specification of a ventilation system for an underground mine, it is necessary to make reasonably accurate estimates of the pressure losses in the various airways of the mine. These estimates can be made with little difficulty for open airways with simple geometric cross-sections, such as those cut by continuous miners or tunnel-boring machines. The situation is much different on a longwall face, where the airway's complex geometric cross section and the presence in the airway of obstructing equipment having a variety of shapes make it difficult, if not impossible, to estimate pressure loss using traditional methods of calculation. Head losses in mine entries are calculated using Atkinson's Equation. [22H= KPLQ (English) H= KP 3Q (SO (1) 5.2AA] where H = pressure loss, in. of H2O (Pa); K = friction factor, lbf•min2/ft4 (kg/m3); P = perimeter, ft (m); L = airway length, ft (m); Q = airflow quantity, ft3/min (m3/sec); and A = flow cross-sectional area, ft2 (m2) In this equation, the friction factor, K, is an empirical constant that describes the aerodynamic roughness of the airway. Typically, the K-factor for a given airway is determined by measuring the factors H, P, L, Q and A in Equation (1) and calculating K. Tables of friction factors calculated in this way are found in textbooks and handbooks that deal with mine ventilation analysis. Unfortunately, very few K-factors have been measured on longwall faces, and the accuracies of those that have been measured are entirely site specific, because of the wide variety of equipment found on longwalls. The development of a technique for prediction without mine-site measurements of the friction factor for any longwall face, regardless of its configuration, will thus be very useful in the design of ventilation systems for mines in which longwall mining is practiced. Calculation of pressure losses using Atkinson's Equation (1) and empirically determined K-factors provides accurate and useful approximations in cases where the airways have relatively simple cross sections. However, a careful analysis using the principles of fluid mechanics shows that such calculations are based on two assumptions that are not strictly correct when there are obstructions in the airway. The first assumption is that the air velocity distribution in the cross section, particularly around the perimeter, is uniform. This assumption results from the fact that the tabulated K-factor values found in the literature are based on field measurements with uniform conditions. Such uniformity does not exist in longwall airflows. The second common assumption is that the K-factor, and corresponding head loss, is independent of the Reynolds Number (NR) for a given flow. In fact, this assumption is not strictly correct, and is particularly erroneous in the case of irregular protuberances into the airflow, such as those found on a longwall face. The errors arising from the assumptions may be avoided by using K-factors calculated by a newly devised method, described below, which takes into account the fundamental principles of aerodynamic drag analysis. This new technique has two advantages: first, it is flexible enough to model any longwall, regardless of equipment configuration; second, it employs terminology and equations familiar to those who perform mine ventilation analysis, using K-factors, for which ventilation engineers have an intuitive understanding, rather than drag coefficients. To provide guidance for development of a longwall drag model, data were taken on two modern longwalls operating in substantially different conditions. Pressure measurements at Mine B were made with 200-foot (61-m) sections of 1/8-in. (3-mm) diameter plastic tubing, attached to a Dwyer Magnehelic gauge. Pressure drops were measured in 200-foot increments down the face, and summed to give the drop for the entire face length. This technique was found to produce small, repeated errors because of the number of segments required to span the longwall. At Mine A this problem was avoided by using a single, continuous, plastic tube for the entire face length. The psychrometric properties of the air were measured for both Mines A and B. A calibrated, standard vane-anemometer was used to measure the airflow on both faces. Finally, numerous dimensions were measured on both faces, and face profile drawings were obtained to allow detailed evaluation of the face equipment geometry. From this information, accurate evaluations of the average wetted perimeter and average area of the longwall face airways were made. Since the airflow is not confined to inside the powered supports at all points along the face, a quadratically weighted average of the airflows measured at various stations along the face was calculated: [n2Qavg =Qi Ii / It(2)i=1] where [Q, avg = average airflow for analytical purposes, ft3/min (m3/sec); Q= airflow at station i, ft3/min (m3/sec); 1= length of segment represented by Q, ft (m); h= length of longwall face, ft (m): and n= number of quantity measurement stations.] The quadratic weighting scheme was chosen because the

Jan 1, 1992