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By R. V. Ramani, V. T. Burgos, J. A. McClay

The systems contributing to the cost analysis, and the flow of data input and output related to these systems, are brought into focus in Figure 6. The various sub-systems of the Master Design Simulator provide the raw operating data basic to the cost model which, operating independently, accumulates the raw input, assigns costs to this data by standard or modified costing procedures, manipulates the costs into standard formats and outputs the data for managerial evaluation. Cost Modeling Direct costing methods are not complex in the sense that elemen¬tary arithmetic is employed using the same basic relations for each cost category. The basic cost model relations described above are illustrated in Figure 7. The greatest difficulty encountered in the transition from a dy¬namic systems simulation model to a costing model is the time frame of the input and output data. Dynamic simulation models utilize a small time increment, on the order of seconds or fractions of seconds, to analyze system operations and interactions. On the other hand, for cost computation and reporting, the smallest relevant time unit is the shift, with reporting periods expanding to days, weeks, months, and years. Complications arise in the accumulation of data for the various report periods due to the use of the Gregorian calendar by modern so¬ciety. The potential for simulation for the life of the mine, possibly in excess of 50 years, increases the complexity of the costing process

Jan 1, 1975

By W. S. Sanner

A High Splint coal was carbonized in a low-temperature, fluidized-bed sys-tem to study the effects of thermal cracking on the products of decomposition. The coal was fluidized in recycle gas at 485° to 600° C, and the products were cracked at 600°, 700°, and 800° C in a bed of fluidized coke. Yields of tar, pitch, paraffins, and olefins decreased as carbonization temperature increased. Thermal cracking of the tar vapors produced the highest tar yields at 600° C, and light oil yield increased at cracking temperatures up to 700° C. At an 800° C cracking temperature, the yield of light oil decreased.

Jan 1, 1969

By S. P. Kinney, A. C. Fieldner, S. H. Katz

"1 Introduction The regrettable death of James S. Cunningham, Foreman Miner, attached to Bureau of Mines Rescue Car No. 2, while wearing a half-hour type oxygen breathing apparatus in a gasoline storage tank at Trinidad, Colorado, raised the question as to the possibility of gasoline vapors permeating the rubberized fabric of the breathing bags of such apparatus.It is known that most gases and especially certain organic vapors permeate rubber, by solution or a similar process. The rubber becomes saturated with the gas and if a concentration of gas is maintained on one side of the rubber sheet it slowly gives off gas from the other side. It of course takes some time for the gas to diffuse through the rubber and the length of time before it reaches the other side is proportional to the thickness of the rubber. The amount of gas that passes through per unit of area in unit time increases with the concentration of gas and also varies with the structure and composition of the rubber.It has been suggested that the gasoline vapor could not have penetrated into the interior of an oxygen breathing bag because the pressure is greater on the inside, but this is not true as the process of permeation by solution in the rubber is affected only by the difference in the partial pressures of gasoline vapor on the inside and outside of the bag. The positive oxygen pressure on the inside can only prevent the entrance of gasoline vapor through measurable holes, and has no effect on permeation by diffusion through the rubber."

Dec 1, 1919

By N. F. LeJeune

For a number of years the Bureau of mines has conducted semi-annual surveys to determine the changes in the characteristics of the motor gasoline being sold in the United States. The Bureau of Mines surveys, from April, 1917, to January, 1943, indicated a progressive decrease in the end point range. The survey for July, 1923 showed an interruption in this progressive decrease. This interruption, as shown in Table 1, in the line marked "Difference," was apparently a definite one, for the data obtained in the surveys of July, 19233, January, 19244, and the present one, apparently substantiate it. The figures in Table 1 were obtained by averaging the end points of the least volatile and most volatile samples of gasoline. For example, of 850 samples analyzed in 1919, the 10 per cent (85 samples) having the highest end points and the 10 per cent having the lowest end points were grouped, and the end points of each group averaged. These averages are represented in the table as the "Maximum 10 per cent" and the ?Maximum 10 per cent," respectively. The same scheme was used on the succeeding surveys.

Jan 1, 1924

By John C. Edwards

To have the capability to predict the development of localized spontaneous heating within a porous coalbed that is subjected to forced air ventilation or in an otherwise quiescent environment in which buoyancy develops, the Bureau of Mines developed three time-dependent mathematical models, which were used to calculate the temperature increase associated with chemisorption of oxygen by the coal. In each model, spontaneous heating is driven by an Arrhenius first-order reaction between the oxygen and coal. Two models are two-dimensional, and one is one-dimensional. In the first two-dimensional model, a constant-velocity forced convection airflow is specified; and in the other, buoyant flow is allowed to develop in the absence of forced convection. The third model evaluates the airflow from Darcy's law and a specification of the pressure at the surface of a one-dimensional porous coalbed. Numerical computations demonstrated how each model could be used to predict the onset of spontaneous heating when the porous coalbed was subjected to constraints of an imposed internal heat source or a high- temperature airflow. The effects of particle size and coalbed compaction upon spontaneous heating were examined with the third model.

Jan 1, 1990

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

SUMMARY The objective of this program was to develop a system to extinguish coal mine fires by remote sealing of the underground passageways. The system developed had to be versatile enough to function under a wide range of operating conditions, including large variations in passageway geometry, depth of mine, water conditions, both in the mine and at the surface, and rubble in the mine passage. The system developed had to include instrumentation for the remote probing of the passageway prior to sealing, a system for sealing the mine passages, and instrumentation for remote monitoring of the quality of the seal during and after construction. These objectives were successfully achieved during this program. The remote mine sealing capability of the system was satisfactc rely demonstrated in a field test conducted at the Eastern Associated Coal Corporation Federal No. 1 Mine in Grant Town, West Virginia. The remote sealing consists of: (1) A sonar initial probing system which can operate satisfactorily even in the presence of dense smoke. The system is capable of determining both the local passageway geometry, identifying the presence of cribs and other obstructions, and the position of the borehole in the mine passage. (2) A mine sealing material system which utilizes fly ash for making the complete seal or as a bulk filler in conjunction with a urethane, froth foam, seal topping system. The choice of using fly ash alone or fly ash with foam topping depends on a number of factors, such as quality of seal desired, time available per seal, depth of borehole, passageway geometry, and water holding require¬ment. The fly ash-foam seal is a better seal, capable of sealing against a higher water head than fly ash alone. The fly ash sealing

Jan 1, 1973

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

9. Remote Sealing System Sensitivity 9. 1 Introduction In the previous sections a description of the overall system has been presented along with detailed descriptions of the equipment and techniques employed with the preliminary probing system, the seal em¬placement system and the seal checking system. In addition, the use of these subsystems in a specific mine application has been described in considerable detail. A broad range of parameters of interest was specified in the contract, as summarized in Section 1. 3. Most of these are a function of the general location; i. e. , the location of the mine, and the specific location; i. e. , the location of the boreholes. These parameters of interest include passage size, shape, depth, slope and water con¬ditions. The length, diameter and location of the boreholes within the mine passage and on the surface are critical parameters as well. A few additional parameters may affect one or more of the remote sealing subsystems. These include temperature, topography, rock and soil conditions, and underground water. While variation in these parameters will not render the system inoperative, consideration of them in the planning stages will simplify and expedite the field operation. In the following sections the effect of the various parameters on the remote sealing operation will be discussed. For clarity, the several tasks, borehole drilling and casing, preliminary probing, fly ash delivery, foam topping and seal checking, will each be considered separately.

Jan 1, 1973

By Harold R. Newman

The performance of Ecuador's mineral industry continued to be affected not only by depressed oil prices in recent years but also by natural disasters. In March 1987, Ecuador canceled foreign debt payments for the rest of the year and appealed for international aid because of a series of earth-quakes that destroyed villages and crippled the nation's oil industry. The earthquake destroyed a key section of the country's main oil pipeline and forced a halt to production and shipment of Ecuador's most important export product. Ecuador produces 240,000 barrels of oil per day and exports 144,000 barrels daily. Oil accounts for 60% of the nation's hard currency earnings. The Government of Ecuador asked the Organization of Petroleum Exporting Countries and other oil-producing countries to assume Ecuador's oil sales commitments. Ecuador agreed to pay the countries back in an equivalent amount of oil when it was able to resume exports.

Jan 1, 1989

By Sarah P. Guerrino

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are the tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed ?mine output.? It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1987

By Robert F. Chaiken

A novel approach to eliminating environmental and public safety hazards that are associated with fires in abandoned coal mines and waste banks involves the use of in situ combustion technology developed by the Federal Bureau of Mines to accelerate the burning of the wasted coals in place. This technology would be used under exhaust ventilation control conditions that would allow for total management of the hot gases produced. Combustion stoichiometries would be optimized to minimize unburnt combustibles and to maximize the heat content of the gas products, which will be exhausted at one or more fan locations. When necessary, scrubber systems would be employed to remove air pollutants, such as sulfur dioxide; heat utilization systems (process heat, steam, and electricity) would also be employed to offset operational costs. Ultimately, complete burnout would solve the fire and acid water formation problems of the abandoned coal mine or waste bank. Pertinent technical data for burnout control are derived and discussed in terms of the important material and operational parameters. In general, it is believed feasible to operate a burnout system in an existing abandoned mine or waste bank fire at thermal power levels in the range of 10 to 100 Mw, and at exhaust gas temperatures of 1,000° C (1,830° F).

Jan 1, 1980

By Jerry L. Huiatt

An accurate and reproducible procedure was developed using the gas-liquid chromatograph to quantitatively measure oleic acid on flotation products and in flotation water phases. The method comprised extraction of the oleic acid from the mineral surfaces with alcoholic NaOH, esterification of the extracted oleate, and chromatography of the methyl ester with an internal standard. Quantitative analysis of oleic acid on flotation products from test tube and bench-scale flotation tests with pure minerals and with natural ores proved the applicability of the method on a variety of minerals. The accountability of oleic acid added was 100 percent, ±5 percent.

Jan 1, 1968

Reduce or prevent acid mine drainage from coal refuse piles and surface mines by inhibiting the growth of acid-causing bacteria. Approach A dilute surfactant or deter? gent solution is applied directly to coal refuse piles or overburden using a hydro-seeder or road watering truck. The surfactant treatment can be used either as a preventive measure to avoid a potential acid drainage problem or to reduce water treatment costs by controlling acid drainage at its source. How It Works Acid drainage is prevented or reduced by inhibiting the growth of Thiobacillus ferrooxidans, a type of bacteria which obtains most of the energy it needs to survive by oxidizing ferrous iron in water. The oxidized iron in turn attacks pyrite, which forms an acid and additional ferrous iron for the bacteria to oxidize. T. ferrooxidans is protected by an outer membrane which enables it to survive in its acid environment. Anionic surfactants, or surfactants containing negatively charged ions, can be used to destroy this membrane, thus killing the bacteria and slowing down the oxidation of acid-forming pyrite. Of the anionic surfactants tested to date, sodium lauryl sulfate (SLS) appears to be the most effective as a bactericide. Alpha olefin sulfonate and alkyl benzene sulfonate are acceptable alternatives. These surfactants are major components of common household products, such as laundry detergent, shampoo and toothpaste. They are, therefore, readily available, inexpensive, biodegradable and present no environmental problems at low concentrations.

Jan 1, 1983

By Michael J. Brnich

Since 1991, Pittsburgh Research Center (PRC-formerly part of the Bureau of Mines) researchers have recorded extensive interviews with 30 individuals who are experts in the area of mine emergency response. These individuals, who have an average of 35 years of mining experience and 29 years of mine emergency response experience, related stories and observations from events that they experienced during their combined 850 plus years in mine emergency response. The purpose of this effort was to gather information that could be passed on to both today?s and tomorrow?s mine emergency responders to train and guide them in handling future events. This is the first of two articles which report the responses that these experts gave when asked how they think people who may have to respond to a future mine emergency should be trained. During the interviews they discussed how training should be conducted, who should be trained, and what topics should be included. This article will cover the first two areas: what training methodologies would be most effective and who needs to participate.

Jan 1, 1997

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

8. Refuge Chambers 8.1 Refuge Chambers - Technical Discussion 8.1.1 Introduction As a part of the overall escape system, refuge chambers can provide a last resort when existing escapeways are blocked. These chambers are intended to provide both protection from toxic gases and a life supporting environment for a period of time before external rescue or further escape efforts can be carried out Escapeways may be blocked physically (due to cave-ins, etc), by fire, or by the presence of a toxic or oxygen deficient atmosphere. In the first two cases, the trapped miners would most likely await external rescue efforts, and hence the design of the chamber will have to consider the time durations that such efforts may take, It is also possible, in the second case, for fire fighting and fire protective equipment to be stored in the chamber so that miners may attempt their own escape. In the third case, it should be recognized that a compact, beltmounted 1-hour self-contained breathing apparatus has been developed(9), and that other, less compact equipment is available for up to 4 hours of self-contained breathing supply. If such equipment were stored in the chambers, then miners could escape by travelling from chamber to chamber, taking temporary refuge in each before proceeding to the next. 8.1.2 Background The concept of "barricading" has long been recommended for those emergencies where miners are trapped inby a fire. Barricading, which is the construction of a makeshift shelter in a crosscut or deadend, protects the entrapped miners from toxic gases and enables them to conserve a supply of air. In this manner, they can survive two or three days--hopefully enough time for them to be reached by rescue teams. In the past, many lives have been saved with this technique.

Jan 1, 1976

By Walter W. Fisher

A kinetic investigation of copper cementation in a revolving drum was undertaken by the Bureau of Mines to explore the effects of a porous copper deposit attached to the iron surface and a fluidized slurry of copper particles surrounding the iron precipitant. The rate of cementation was found to be significantly enhanced by the increased cathodic areas provided by a porous copper deposit or the presence of a fluidized bed of copper particles contacting the iron precipitant. The cementation rate was found to be retarded by increased ionic strength, low pH, and the presence of oxygen. The cementation reaction was first order with respect to precipitant surface area. Copper cementation on iron is visualized to occur by two basic mechanisms. Precipitation may occur through a series of shorted electrochemical cells, whereby cupric ion precipitates on a growing cathodic copper deposit, or, deposition may occur via a fluidized cathode of copper particles contacting the ion precipitant.

Jan 1, 1976

By Anthony T. Lannacchione, Donald G. Puglio

The Bureau of Mines developed data on the methane content of the Hartshorne coalbed, Haskell and Le Flore Counties, Okla. The methane content is calculated to be between 1.1 and 1.5 trillion cubic feet, based on an estimate of total coal in place of 2.4 to 3.2 billion short tons. Methane increases with depth, but the rate of increase decreases with greater depths. Degasification in advance of mining is recommended for all mines operating at depths greater than 500 feet to reduce hazards and methane explosions, decrease mine ventilation costs, and conserve the natural gas that would be otherwise wasted.

Jan 1, 1979

By Robert J. Willard

This chapter includes tables for 1982 that were not available in time for publication of the 1982 Minerals Yearbook, but does not include corresponding tables for 1983. The value of raw nonfuel minerals produced in the United States during 1988 was estimated at $21.1 billion, an increase of $1.5 billion over the value for 1982. This is a reversal of last year's downturn in value from that of 1981, which was the only decrease noted since 1971; hence, an overall trend of increasing values has been maintained for 12 years, except for 1982. Although the reversal is a basis for cautious economic optimism, it is tempered by continued problems in the domestic mining industry: inadequate funds for capital investment and competition with other countries that have lower production costs. Output of metal commodities in 1983 increased for 8 out of 21 metals, and metal values, in general, increased for 9 of the metals. Output of nonmetal commodities was mixed, with 24 nonmetals showing increases, 20 showing decreases, and 2 unchanged. Nonmetal values were also mixed in 1982: 25 showed increases, 20 declined, and 1 was unchanged. Improvements in the international metals market have not been forthcoming because of the continued depressed prices for major metals. Governments in foreign producing countries have been concerned with maintaining employment and continuing foreign exchange flows through mineral exports. Consequently, the excess of supply in the face of shrinking demand brought downward pressure on metal prices in general, except for the precious metals. On the domestic front, this situation means U.S. mining companies must become even more cost efficient. The major trend in the mining industry in 1983 was to cut costs further, reduce or stabilize total production, reduce outlays for major capital equipment, modify existing systems and equipment, and streamline operations. Most of the accomplishments reported herein reflect this trend.

Jan 1, 1984

By W. J. Fene, H. B. Humphrey, J. J. Forbes

"INTRODUCTION Loss of life from coal-mine explosions in the United States in 1949 was the lowest in any year since before 1870. Although fatality reports from coal nines before 1910 were incomplete,' the explosion fatalities from single disasters or individual States exceeded the 1949 total in each year as far back as 1870, when the records become fragmentary. Since 1890, the only other year in which fewer than 35 were killed was 1946, with a total of 32. Figure 1 shows the total yearly fatalities from explosions in all coal mines and those in anthracite mines alone since 1870. The fatalities in bituminous coal mines were not completely reported before 1910, but enough reports were issued by major coal-producing States to compile reasonably representative figures back to 1885. Any corrections would be additions to these totals.The reason for the moderate total of 46 explosion fatalities in 1948 and the low total of 8 killed in 1949 is thought to be the serious and careful attention devoted to elimination of coal-mine explosion hazards after the disastrous explosions in 1947. The standards now being observed generally with respect to ventilation, rock-dusting, and inspections for gas are better than those found earlier in even the mines having the best reputations for safety. Exceptions are still numerous, but they are fewer, month by month, because of the pressure of Federal and State inspections and a changing conception of the hazards that should not be permitted underground. The prevailing precautions have not eliminated all ignitions of gas or dust, but they have limited propagation to small explosions and have prevented serious loss of life.The number of ignitions (14) reported for the year was less than the average (24) for the 5 years 1944-48 and only half the average for the fiscal years 1929-44. Another favorable factor is that Bureau of Mines representatives were probably in closer contact with both small and large mines in nearly all coal-mining districts. Inspectors now assigned to individual districts are better able to keep informed on the happenings and the progress of safety in their districts. In 1948, one-fourth of the explosions were in mines that employed fewer than 10 men; this condition was duplicated in 1949."

Jul 1, 1950

By Charles L. Kimbell

Bulk carriers, freighters, and tankers are the three classes of seagoing vessels engaged in transporting mineral commodities. However, vessels in these classes are not wholly devoted to mineral commodity transport, as seen in tables 16 through 22. Bulk carriers move considerable tonnages of agricultural products as well as crude minerals, their concentrates, mineral fertilizers, and the like. Freighters, owing to their great variety, can be devoted wholly to hauling mineral products or wholly to non mineral goods, as well as carrying mixed mineral commodities and non mineral commodities. They include general cargo ships, full container ships, partial container ships, roll-on/roll-off ships, and barge carriers. Tankers, although largely engaged in moving crude oil and refinery products, also transport liquid chemicals, molasses, wine, liquefied natural gas, and other fluids. Table 16 shows the distribution of the world's merchant fleet by vessel type in terms of the number of vessels, their gross tonnage, and their deadweight tonnage. The increase of nearly 1.5 % in the number of vessels between 1990 and 1991 compared with a 2.7% growth in gross tonnage and a nearly 2.3 % increase in deadweight tonnage points to an increase in the average size of vessels. Of the four categories of vessels reported, all showed increases in number and in deadweight tonnage between 1990 and 1991 except for "other," and on the gross tonnage basis, all groups registered increases. Although physical characteristics of vessels such as size, draft, crew requirements, type of propulsion system, ratio of gross tonnage to cargo tonnage, and fuel costs have undeniable influences on shipping industry performance, problems of and changes in the quantity and types of materials moved also significantly affect the shipping sector of the world economy, and thus have a bearing on the minerals sector of that aggregate. Unfortunately, comprehensive global data reflecting changes in these critical variables are not published.

Jan 1, 1993

By Peter J. Clarke

Afghanistan's mineral industry continued to be dominated by the production and export of natural gas, although several mining and related industrial projects, all under the supervision of Soviet technicians, were in the planning stage in 1982. Afghanistan produced minor quantities of barite, cement, coal, fertilizer materials, iron, and lapis lazuli, all for domestic consumption.2 Large-scale projects being investigated were a copper mine and concentrating plant at Ainak, extensive mining of the Hajigak iron ore deposit near Kabul, construction of an oil refinery at Angot, increasing production and processing of natural gas, and implementing an intensive geologic prospecting and exploration program for areas of mineral potential. Afghanistan's gross domestic product (GDP) was estimated at $2.76 billion3 and has remained stagnant for the past several years. Total exports in 1982 were estimated at $700 million, only a marginal increase from the 1981 figure of $694 million. Exports of natural gas to the U.S.S.R. earned $385 million in 1982, representing just over one-half of Afghanistan's total exports. Natural gas revenues were down approximately 11% from the 1981 level, owing primarily to increased antigovernment activity in the northern part of the country.4 About 90% of the country's natural gas production was exported to the U.S.S.R.5 About 38% of Afghanistan's development budget had been earmarked for mining and industrial projects in 1982.6

Jan 1, 1984