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By Larry A. Lass

The U.S. Bureau of Mines, in cooperation with the Iron Range Resources and Rehabilitation Board, investigated the potential of using northeastern Minnesota papermill waste sludges as a binder for Mesabi Range iron ore (taconite) concentrate. Sludges from five different commercial papermill waste treatment operations were evaluated in laboratory tests. Except for the coarsest sludge, all were fairly easy to blend with the taconite concentrate using conventional mixing methods. The coarsest sludge had to be reslurried at 2 pct solids before adding it to the concentrate in order to obtain pellets without visible sludge clumps. Drying and grinding the sludges made them less effective as binders because of a lower degree of rehydration. On a dry weight equivalent basis, twice as much raw sludge binder was required to obtain similar pellet physical properties as with bentonite; however, the pellets made with raw sludge had superior metallurgical properties. Over 30 pct higher reduction rates and over 1500 C higher softening temperatures were obtained with sludge binder than with bentonite. Sludge D, which had the lowest fiber and the highest alkali metal content, resulted in the lowest reducibility enhancement. Even though more raw sludge was required than bentonite, the sludges have virtually no value, and therefore may provide a cost-effective additive binder for producing improved metallurgical-quality pellets. Large-scale testing has not been done to confirm these laboratory results.

Jan 1, 1989

By Robert P. Vinson

This Bureau of Mines report presents the results of tracer gas studies conducted at three facilities where bagger hoods had been installed several years ago to remove airborne silica dust from the vicinity of the bagging operator. The studies indicated that for optimum benefits makeup air must be evenly dispersed, the hood enclosures and duct systems must be as airtight as possible, the average intake air velocity of each hood should be at least 200 fpm, and the hoods and duct systems must be properly maintained.

Jan 1, 1981

Commodities statistics and other information are available through the following three systems: Internet Access: To acccess the USBM Gopher server on Internet, connect to: gopher.usbm.gov port 70, using gopher client software. Or contact the Systems Administrator for technical questions: Matt Klevemann, 412-892-6499 (klevemmc@miner.usbm.gov) These USBM materials are available on Internet, with more to come in the future: Publications and other research findings, including this bimonthly publications list, newsletters, tech transfer updates, enviromental technology research, health and safety information. USBM software products Media materials and speeches. Mines Data: Computer bulletin board. Log on via modem through 202/501-0373, or call 202/501-0406 for technical assistance. Mines FaxBack. Return fax service. 1. Use the touch-tone handset attached to your fax machine's telephone jack. (ISDN [digital] telephones cannot be used with fax machines.) 2. Dial 202/219-3644. 3. Listen to the menu options and punch in the number of your selection, using the touch-tone telephone. 4. After completing your selection, press the start button on your fax machine.

Jan 1, 1995

By Pablo Velasco

After becoming an oil exporter in 1972, Ecuador experienced a remarkable economic upswing until 1978. However, in 1979 and 1980, a combination of only slight improvements in agricultural output and stagnating petroleum output lowered rates of real gross domestic product (GDP) expansion to 5.3% and 4.3%, respectively. In current prices, the GDP in 1980 was estimated at $11.3 billion.2 The slowdown in growth is attributable in large part to the low level of petroleum exploration in the 1972-79 period. Ecuador's production of petroleum declined 4.5% in 1980 compared with that of 1979. The consortium of Corporación Eatetal Petrolera Ecuatoriana (CEPS), the State oil company, and Texaco, Inc., operating in Ecuador's eastern jungle region was responsible for nearly all of 1980 production, The volume of total crude petroleum exports from Ecuador dropped from 44.7 million barrels in 1979 to 40 million barrels in 1980, although crude petroleum export revenues rose from $1,032 million in 1979 to $1,294 million in 1980- The latter figure represented 54% of Ecuador's 1980 merchandise exports. Crude oil exports accounted far about 46% of the value of 1979 merchandise exports. The total nonfuel mineral exports in 1980 were valued at less than $1 million.

Jan 1, 1982

"When a metal-mining company takes out a workmen's compensation insurance policy, it does so to relieve itself of its uncertain and variable financial liability under laps requiring payment to employees for lost-time accidents, there-by passing the liability or to the insuring agency. For this service, or rather for the assumption of the risk, the insuring agency charges the mining company a price, or in insurance parlance, ""a premium"".The insuring agency depends upon a volume and variety of business to average the losses incurred by its individual policy holders, and determines its price to cover losses that are suffered and its cost of doing business.It is generally known that all types of insurance are founded on the theory of probability applied to large groups of risks, Workmen's compensation insurance is no exception, and the average price paid therefor must be based on the frequency and severity of accidents in the particular industry or branch of industry under consideration. The frequency and severity rates are determined by statistics, which, of course, unless standardized, kept carefully and consistently, and analyzed properly, are liable to be inaccurate and misleadingThe importance of large groups in arriving at an average price for insurance service can not be overestimated, For example the writer knows of one small group of some twenty metal-mining companies whose losses during the past two years exceeded their premium charge by 54%. Not a single individual company during the two years kept its losses below the premium rate. For several years the group as a whole has persistently exceeded its premium rate, Such risks are not profitable to the insuring agencies and can only be carried where a large volume of good risks will balance the poor risks, but in order to conform to good insurance ethics the premium rate must be based on averages for the industry as a whole, and kept sufficiently low to induce operators to sell their risks."

May 1, 1924

By Merwin H. Howes

In constructing the NORAD Combat Operations Center, controlled blasting techniques were employed to achieve smooth walls and to avoid shattering the rock beyond excavation lines. Extraordinary measures were taken to stabilize the rock to permanently preserve the openings. Rock stabilization was accomplished by means of reinforced concrete and gunite linings, rock boltings, installation of chain-link fabric, and epoxy resin and cement grouting. A particular zone of weakness at a vital location was supported by exceptionally thick reinforced concrete lining, rock bolts, and cement grout.

Jan 1, 1966

By Laurence G. Trudell

A geologic framework for interpreting stratigraphic and geographic variations of the Green River Formation in the Piceance Creek Basin is developed from lithologic data accumulated by the Bureau of Mines from oil-shale coreholes. From detailed Bureau of Mines descriptions of samples from nine coreholes and supplementary lithologic data from seven additional sampled sections, three cross sections were constructed along lines transecting the basin. Plotted as lithologic columns with corresponding oil yields and resistivity logs, the sampled sections are correlated on a time-stratigraphic basis. Distribution and correlation of nahcolite and halite zones are shown, and the approximate base of leaching of these saline minerals is indicated. General lithologic characteristics of members and zones are discussed and interpreted. Large-scale lithologic logs illustrate the nine Bureau of Mines core descriptions, and the complete description of Bureau of Mines-Atomic Energy Commission Colorado Corehole No. 1 is included in an appendix. The time-correlated cross sections provide a necessary framework for understanding the depositional history of the Green River Formation and will facilitate evaluation of oil shale and other mineral resources in the Piceance Creek Basin.

Jan 1, 1970

By M. Karmis

Surface subsidence is an inevitable consequence of many underground mining operations and has been recognized as such since the fifteenth century. Damage resulting from this phenomenon ranges from simple land settlement to severe structural damage to buildings and has been witnessed in rural (Illinois, Colorado, West Virginia, Virginia, Pennsylvania) as well as in urban areas (Pennsylvania, West Virginia, Illinois, Wyoming). In fact, it is estimated that over 2 million acres of land across the United States have been affected by mining subsidence, of which 140,000 acres are in urban areas (Singh, 1978; Johnson and Miller, 1979). Further, it is estimated that during the next twenty years an additional 1.5 to 2.4 million acres of land will also be affected by mining. Subsidence prevention is not feasible, at least under the existing technologic and economic constraints of underground coal mining. Foreign experience has demonstrated, however, that subsidence can be successfully controlled if an accurate method of predicting ground movements is available. Such techniques have been developed in many coalfields, where it is currently accepted that subsidence can be predicted within ± 20 percent of the actual values. Furthermore, such movements can be translated into anticipated structural failures using established damage criteria, thus enabling appropriate precautionary measures to be implemented.

Jan 1, 1983

By R. M. Santmyers

Of the sand and miscellaneous silica produced in the United States , ordinary sand and gravel are , of course , the most important, at least as regards volume of output . The building- construction industry absorbs approximately 75 per cent of the total value of all quartz and silica , as shown in Table 2 of Quartz and Silica, Part I, under "General summary . " Because of their unusual physical properties tripoli and diatomite find extremely wide uses in industry, and as the commercial deposits of these ninerals , especially tripoli , are scattered, large quantities enter into interstate commerce . Whereas ordinary sand and gravel are bulky commodities , these specialties have a fairly high unit value and hence can be transported relatively long distances .

Aug 1, 1931

By James M. Spear

Sample results suggest the only mineral resources in the study areas are placer gold deposits along the South Fork Kern River in the Woodpecker RARE II unit (fig. 1). These deposits, in Rockhouse Basin, total 4.5 Figure 1.--NEAR HERE. million cu yds (3.4 million cu m) of indicated subeconomic gold resources in four deposits of "older" gravel. Gold value in samples averages $0.36 per cu yd ($0.47 par cu m) and is as much as $4.44 per cu yd 1/. Cost of mining the gravel and recovering the placer gold is estimated to be more than $2 per cu yd ($2.62 per cu m) for a deposit of this size and type. Additional inferred subeconomic placer gold resources with similar grade probably occur in four other deposits of "older" gravel on which no mining claims were located. Placer gold occurrences on upper Trout Creek contain gold worth as much as $4.50 per cu yd ($5.88 per cu m) 1/. Average grade is much lower, and only about 1,000 cu yds remain (760 cu m). These occurrences do not constitute a resource, but may attract hobbyists not dependent upon making a profit.

Jan 1, 1982

In 2006, a total of 280 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Metal mines were the smallest mining commodity sector, comprising 1.9% of all mining operations. ? Gold mines comprised 46.8% (n=131) of all metal mining operations. Other common types of metal mines were copper ore (n=34; 12.1%), and iron ore (n=33; 11.8%). Nevada had the largest number of metal mines (n=53; 18.9%), followed by Alaska (n=31; 11.1%).

Sep 1, 2008

By Albert L. Toenges, Theodore R. Jolley

"INTRODUCTION The construction of frame houses (fig. 1) in recent years instead of the conventional sod hut (igloo) (fig. 2) by the Eskimos in the villages along the Arctic Ocean has increased the demand for fuel in these villages. The frame houses, which are not insulated against extreme cold and are difficult to heat, are equipped with Goal stoves. The well-insulated sod huts were heated comfortably with whale-oil stoves. In some years whaling is Door, consequently there is a demand for solid fuel.The Eskimo villages usually are on the sand spits at the mouths of rivers and points of land near the best fishing and hunting grounds. These narrow necks of land usually are sand bars that are not underlain with coal, and coal must be transported to the villages. Lack of development of coal deposits in the Arctic has made it necessary to import coal from the States, generally from 'Washington, to supply these villages. This coal is imported by boat and is received once a year. Its cost is, high, and development of coal deposits in the Arctic to supply these native villages should result in a considerable saving to the Government-operated schools and hospitals as well as to the natives.Early traders attempted to establish coaling stations in the Arctic, and the Eskimos generally know where the coal deposits are situated. A. reconnaissance of a number of deposits in the Arctic was made in the summer of 1946 by engineers of the Coal Division, Fuels and Explosives Branch, Bureau of Mines, and this report describes the areas investigated and suggests plans for the development of some of these deposits."

Dec 1, 1947

By C. B. Manula

Simulation continues to hold the spotlight among the Operations Research applications in the operational side of mining. One reason for this is the need to solve the many waiting line and storage problems common to the industry. A second reason for using simulation is the central requirement of retrospect testing. Acceptance of a model by management is more likely to depend on its tested performance rather than on the underlying validity aspects of the model itself. Mathematics have not been and may not be developed that will allow all desired system elements to be considered simultaneously. It is in this realm that simulation bridges the gap between theory and useful design procedures. One of the earliest published accounts of simulation at work in the coal industry is demonstrated by the application cf Monte Carlo methods to explore changes in future operating policies for an existing track system (Manula, 1963). By modifying certain control parameters, revision in design changes were evaluated in the computer rather than in the actual production section. A second application which has found wide use in practice is the VFI-OCR Face Simulator (Prelaz et al., 1968). The model developed here has the purpose of allowing the comparison of methods for room-and-pillar face operations end observing their effect on mining prior to actual installation. Proposed changes are tried in the model and the best of these are selected as a guide for better mire management: IBM's own simulation package, the System 360 General Purpose Simulator, has experienced heavy use in solving similar problems and other steady-state situations.

Jan 1, 1974

NIOSH research has focused on the monitoring and the control of methane levels in active mine workings. Response times for instrumentation using catalytic heat-of-combustion sensor technology were evaluated. NIOSH research has modelled the flow of methane gas onto long-wall faces and gobs, developed engineering controls to limit methane levels during mining, and designed coalbed and gob degasification systems. Available methane control systems have been challenged by recent developments in longwall and room-and-pillar mining systems. This includes increased face advance rates leading to increased productivities, increased longwall panel sizes, and the generally deeper workings of U.S. coal mines. The potentially violent nature of any underground explosion or ignition requires the measurement, control, and reduction of methane emissions into the mine environment for continued worker safety.

Jan 1, 2008

By G. Richards Gwinn

The mineral graphite, a form of carbon, has been known for hundreds of years, and, was first used commercially as a coloring agent. Its true identity, however, was not recognized until the end of the eighteenth century, and its commercial development did not become extensive until near the close of the ninteenth century.

Jan 1, 1943

By E. Chin

The domination of Bangladesh's mineral industry by natural gas was in for some possibly significant changes. A modest flow of crude oil was struck in a gas development well in the northeastern corner of the country. This was the first commercial flow of crude oil in Bangladesh. All crude oil was being imported, which cost a significant proportion of the nation's foreign exchange earnings. The development of an oilfield producing only a few thousand barrels per day would be a welcome help to the economy. Additional exploration at a 1985 coal discovery in the northwest indicated a considerable reserve of good-quality coal at a depth suitable for mining. If the coal is mined, it would be a boon to the local economy because natural gas was not available in the area.

Jan 1, 1988

By A. J. Kraemer

This paper is the second and concluding report of the results of the twenty-fourth semiannual survey made by the Bureau of Mines of motor gasoline marketed in the United States. The first report7 on this 1931 survey gave the results of the examination of the gasoline samples in accordance with the new Federal specification for United States Government Motor Gasoline.8 The present paper reports results of the examination of the gasolines for color, doctor test, gravity, end point, per cent recovered, copper-dish gum, and steam-oven gum. The retail price and the tax at the time each sample was taken are also reported.

Jan 1, 1932

By Ernest A. Curth

A 3-month study in 1971 of the Essen Roof Support and Rock Mechanics Research Center's program of roof and support evaluation included 25 mine trips. German miners must adopt mining methods and environmental control measures involving methane drainage and water infusion to improve productivity under severe natural conditions. Pressing problems in ground control must be solved such as cavities in front and above the supports at longwall faces and excessive convergence in gate roads. The Center developed automatic data processing methods to quantify the results of roof and support surveys and to establish criteria. Another approach to ground control is the study of mine models. The Center's laboratory has the facilities to test elements of powered roof support and whole assembled units. Face automation and roof control by powered shields are novel developments that are under close scrutiny in the field as well as in the laboratory. Though the Essen Center's roof and support evaluation techniques are tailored to the needs of the coal mining industry of the Federal Republic of Germany under conditions vastly different from those in the United States, some application may be found here, for instance, monitoring faces and roadways and preventive maintenance of hydraulic systems.

Jan 1, 1974

By Kenneth H. Johnston

This report describes an in situ combustion project and three waterflood projects in Allen, Anderson, and Wilson Counties, Kansas, that will be visited during the 1964 annual tour of the Kansas-Oklahoma Waterflood Association. Among the unique features of the projects are the movement of heavy crude oil through the reservoir and into the wellbore with energy furnished by burning a portion of the crude oil therein. Another feature is the simultaneous injection of C02 and water, through separate tubing into input wells during early development, to increase injectivity at moderate pressures, Discussion of individual projects includes information on their early history, source and treatment of injection fluids, oil production-decline curves, and the results of water injection on oil production.

Jan 1, 1964

By Thomas E. Lobb, Harry C. Verakis

This article examines the factors related to injuries due to inadequate blasting shelters and blast area security, and identifies mitigation techniques. The key concepts are:(a) accurate determination of the bounds of the blast area, (b) clearing employees from the blast area, (c) effective access control, (d) use of adequate blasting shelters, (e) efficient communications, and (f)training. Fundamentals are reviewed with an emphasis on analyzing task elements and identifying root causes for selected blasting accidents. Mitigating techniques are presented along with discussions and examples.