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By Gary Schaffer, Anthony Stentz

Surveying of mines is a necessary step in coal mining to assemble maps which are used for tracking progress in the development of the mine and to plan future coal removal. A first approach for automatically building high-resolution two-dimensioml maps of underground coal mines is presented. The technique assembles laser rangefinder scans obtained from several locations within the mine into a consistent global map of the mine. Each range scan comprises thousands of data points collected in one second, thereby achieving higher resolution and much faster measurement compared to a human using a transit. The raw data (range scans) are processed to fuse them into a consistent representation. This paper describes a first approach to automated surveying and presents initial results of merging range scans. Improvements to the scan-merging algorithm are proposed.

Jan 1, 1993

By G. F. Friel, G. S. Morrow, J. C. Edwards

An experimental program in the U.S. Bureau of Mines' Safety Research Coal Mine evaluated the effects of dead end crosscuts on the transport time of CO along a mine entry. The presence of carbon monoxide is a characteristic of a fire in its incipient stage, and is significant in the determination of a fire location in a mine from the analysis of arrival times of pre-set concentrations at CO monitors. In this investigation two entries, with a total of ten crosscuts, connected by a room were instrumented with CO sensors as part of a real-time monitoring and data acquisition system. Controlled release of 1% CO was monitored as the contaminant traveled the entries for several different configurations of CO sensors and exhaust fan settings. In addition to the normal longitudinal dispersion of CO due to turbulent mixing at the front of the CO wave, the induced rotation of air established within a crosscut by the entry flow diluted the CO concentration through entrainment. It was determined experimentally for the entry and crosscut configuration considered that the transport time for a specified CO concentration was 27% greater than the predicted time based upon entry volume only, but 13% less than the predicted time based upon entry and total crosscut volume. The proper interpretation of the measured transport time of a specified contaminant concentration between sensors is important for mine safety in the isolation of a fire and plans for miner evacuation.

Jan 1, 1993

By Ottmar Burghardt

Sintering of iron ore has undergone a dramatic development world-wide. Today, the annual world production amounts to approximately 600 million tons. At present, the sintering process in competition with pelletizing, seems to offer certain advantages inasmuch as it allows the use of solid fuels. Also, its charging behaviour in the blast furnace is, in general, considered as being better than that of pellets. This is true, in particular, for the charging behaviour and the gas permeability in relation to the grain size. Moreover, instead of charging limestone into the blast furnace, for instance, the basic components which are necessary for the burden materials can generally be supplied in a simpler and more cost-effective way by using basic sinter instead of basic pellets. While in sintering, with basicity rising to the range of 1.6 to 1.8 CaO : SiO2, the capacity increases and the sinter quality shows improvements in most of its characteristics, the pro¬duction of basic pellets generally requires a higher fuel rate, when compared to acid pellets, while production capacity decreases and some of the quality characteristics deteriorate.

Jan 1, 1982

By J. H. Rowland

Four different types of fire suppression systems were evaluated in large-scale fire experiments to study the effect of air velocity on the effectiveness to extinguish conveyor belt fires. The four different types of suppression systems were water sprinkler, deluge type water spray, and two different dry chemical fire suppression systems. The large-scale fire tests were conducted with 72-in-wide fire resistant rubber belt that met the Mine Safety and Health Administration flame resistant requirement specified in Title 30, Code of Federal Regulations, Part 18, section 18.65 (also known as the 2G Flame Test). Each fire suppression system was tested at air velocities of 500-550 feet per minute (fpm) and 1350-1500 fpm. Two tests were conducted at both air velocities for each fire suppression system. Both of the water-based fire suppression systems were able to suppress the fire to the point that a miner could extinguish it with a fire extinguisher. However, the amount of water needed to suppress the fire to the point where a miner could walk up to extinguish any smoldering belting was greater than the current MSHA regulations require. MSHA regulations only require 10 minutes of water supply to the suppression system. In the test set up neither of these systems would have suppressed the fire had the water been turned off to the system after 10 minutes. The dry chemical suppression systems produced mixed results. Dry chemical suppression system A did not suppress the conveyor belt fire at either air velocity. Dry chemical system B suppressed the fire at 500 fpm air velocity, but produced mixed results at the higher air velocity. Details are presented on the large-scale fire test set-up, arrangement of the fire suppression systems, and conclusions regarding the effect of air velocity on fire suppression system design and performance. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

Jan 1, 2009

By T. Yegulalp, K. S. Lackner

Zero emission coal plants capture their own CO2 emissions. Since they have no smoke stack, they emit no pollutants to the air. Zero emission plants circulate a gas stream, to which fresh fuel is added and from which spent fuel and impurities are removed as solids or liquids. Coal is gasified via hydrogenation, steam reforming or CO2 gasification (Boudouard reaction). The gas is oxidized in a fuel cell and the resultant water and CO2 are partially removed before returning the remaining gas to the gasifier. The high conversion efficiency of zero emission power plants, which exceeds 70% even in realistic designs, stems from combining fuel cells with careful heat management. The paper generalizes the concepts and outlines the thermodynamic basis of zero emission power plants.

Jan 1, 2004

By T. E. Garnar

Heavy mineral mining has been a small, but important Florida industry over the past sixty years. Early geologic history of each deposit is similar up to point of deposition in alluvium, deltaic sediments, or along shorelines. Later geological development through reworking and concentration is different for each deposit. The Trail Ridge deposit was formed by reworking Citronelle sediments of the Lake Wales ridge. Post depositional leaching of iron from ilmenite makes Trail Ridge an important source of titanium minerals for TiO2 pigment manufacture. Research leading to the separation and sale of by-product heavy minerals from Florida deposits has been important in maximizing profitability. Advances in mineral dressing technology will lead to future mining of lower grade reserves. Future needs for heavy minerals seem certain to expand, with increased activity in exploration and development of mining operations.

Jan 1, 1972

By William R. Bond, Jim V. Rouse, Laura L. Damon

As noted by Damon (1990), "The time that a heap (of gold ore) is on the reusable leach pad is of critical economic importance." The Interim Neutralization Study, conducted by Brohm Mining Corporation (Brohm), at the request of the South Dakota Department of Water and Natural Resources and reported by Damon indicated that improvements could be made in leaching and pointed out the need for a better understanding of the gold ore leach procedures. To provide data on an actual heap, personnel from Brohm and GEOCHEM installed a series of pressure/vacuum lysimeters in an active Brohm heap, and conducted subsequent testwork to evaluate the efficiency of leaching. The objectives of the testwork included efforts to:

Jan 1, 1992

By D. G. Millette, A. J. S. (Sam) Spearing

The design of a cost effective backfill system involves many aspects and various inputs from different engineering disciplines. Backfilling is a very significant mining cost and efforts need to be made in the design stage to maximise efficiency and flexibility whilst minimising costs. The aspects that need to be considered include the following: Required fill performance underground Peak and average fill tonnage requirements Backfill scheduling in the mining cycle Material selection, testing and preliminary costing Plant design and storage needs Infrastructure requirements Implications on surface waste/tailings disposal and costs Total backfill costs In order to produce a cost effective and efficient backfill operation, a multi-disciplinary project team is required that should include the following skills and functions: Mine Planning Rock Engineering Metallurgy Mechanical Engineering Environmental Health and Safety Tailings Disposal/Waste Management This paper discusses the above and indicates important aspects that should be considered.

Jan 1, 2001

By Morris Loshinsky, George Ziegler

The New York City Transit System is celebrating its Diamond Jubilee this year. In 1904, 9.3 route miles of New York's first subway was placed in operation in lower Manhattan. Since that date the system has grown to 230 route miles and 458 stations (See Exhibit #1). The age of the system immediately provides a clue to the nature of our construction activity. While we must always plan for the future and expand the system in the direction of the future needs in New York, a substantial amount of time and money must be channeled towards the modernization and maintenance of the existing system which provides vital transportation for 3-1/2 million passengers a day. This paper however will be directed to our New Route's Construction and, specifically, to three rock tunnel and cut and cover sections presently under construction. Currently, New York is engaged in the construction of about 9 New Route miles of structure. Briefly, the 3 Sections we will discuss are as follows: Route 131-A Section 5A is a 4 track structure in Manhattan and includes the new Lexington Avenue Station. This 1240 foot long section is located between Park Avenue and 3rd Avenue and is a combined cut and cover and rock tunnel section under 63rd Street. Route 131-A Section 5B is an intricate 2423 foot long 4 track rock tunnel section extending from 3rd Avenue to the FDR Drive under 63rd Street in Manhattan.

Jan 1, 1979

By K. P. Bingham

Lime is one of the largest volume chemicals produced in the United States. In 1979 approximately 21 million tons were produced. Lime is, in fact, second only to sulfuric acid as the largest volume basic chemical produced. Lime, also known as quick lime (calcium oxide) and hydrate lime (calcium hydroxide), is the principle alkali used in a multitude of industrial processes. In addition to its use as a principle industrial alkali, lime has experienced dramatic growth in four general market areas during the past 30 years. These four areas are: 1. Water Treatment - Lime is used extensively in treating and purifying water for industrial and potable use, Although significant tonnage is shipped to this market of municipal and industrial water treatment plants, the end-users are widely spread geographically and individual shipments are relatively low tonnage. Lime, which is nonhazardous, can safely be shipped by truck or rail to these small end-users. 2. Municipal and Industrial Waste Treatment - Environmental agencies at all government levels,

Jan 1, 1980

By R. A. Wharton, Z. Yang, R. W. Smith

The electrokinetic and flotation behavior of the green alga Chlorella vulgaris was studied in the absence and presence of Pb(II), Al(III) and flotation collectors. It was found that the presence of Al(III) is necessary for good flotation of the organism, whether or not Pb(II) is present, when dodecylammonium chloride or sodium dodecylsulfate is used as collector. Best flotation using dodecylamine is at about pH 8, and best flotation when using sodium dodecylsulfate is at about pH 4. It appears because of the small size of the organisms that the Al(III) is necessary for flocculation to enhance bubble-cell contact and C. vulgaris removal from water. When N-dodecyl-2-aminopropionic acid is used as collector, good flotation occurs at about pH 4 without the addition of Al(III).

Jan 1, 1992

By D. L. Purcell, B. T. McClure, J. McDonald

The U.S. Bureau of Mines has completed a laboratory evaluation of exhaust emissions from a diesel engine using an oxygenated diesel fuel. The fuels tested were soy methyl esters in a neat (100%) form and low sulfur, petroleum number 2 diesel fuel (D2). The engine tested was a Caterpillar 3304, indirect injection, naturally aspirated, 75 kW, diesel engine that is typical of engines used in underground mining applications. The objective was to determine the extent to which oxygenated fuels, such as methyl esters, reduce diesel particulate matter (DPM), and their influence on upon gaseous emissions such as total hydrocarbons, CO, NOx, NO2, formaldehyde, and other exhaust emissions. Heavy- and light-duty transient tests were used to simulate load cycles typical of mine applications. The soy methyl ester fuel produced greater amounts of volatile DPM (organic material) but much less nonvolatile DPM (carbon soot) for overall DPM reductions. A diesel oxidation catalyst (DOC) typical of the type commonly used in metal and nonmetal mines was tested with both fuels. The DOC further reduced the volatile and total DPM when used with the soy methyl esters, but increased the total DPM for D2 due to sulfate formation. The soy methyl ester fuel reduced CO and hydrocarbon, and NOx emissions. The DOC further reduced CO and hydrocarbon emissions.

Jan 1, 1995

By D. L. Misterek, E. J. Slebir, G. W. Ring, M. A. Laird

INTRODUCTION In 1973, the Federal Highway Administration (FHWA) initiated a 10-year program of research on tunneling technology for future highways as a part of a larger Department of Transportation effort on tunnels. The objectives of the FHWA program are to: improve tunnel design technology, reduce costs, minimize adverse environmental impact due to construction, increase the rate of construction, and assure the maintenance of a safe and attractive tunnel environment. The program is divided into four research tasks designed to solve tunneling problems identified by the engineering and field offices of the FHWA. These tasks are as follows: 1. Cut-and-Cover Tunneling 2. Site Investigations 3. Ground Movements - Prediction and Control 4. Highway Environmental Criteria for Tunnels In order to provide input into Tasks 2 and 3, the FHWA is sponsoring an investigation and testing program by the U.S. Bureau of Reclamation to instrument and monitor two sites in the second bore of the Eisenhower Memorial Tunnel located on Interstate Highway 70 at Loveland Pass approximately 97 km (60 miles) west of Denver, Colorado. The tunnel will be approximately 14.0 m (46 ft) in diameter when excavated. The study is designed to generate data on: (1) changes in the state of stress, and movements during and after tunneling, (2) tunnel lining design requirements, (3) developing a

Jan 1, 1976

By K. H. McDaniel

Eight mine weather stations (MWSs) installed at the Waste Isolation Pilot Plant (WIPP) to monitor the underground ventilation system are helping to simulate real time ventilation scenarios. Seasonal weather extremes can result in variations in the natural ventilation pressure (NVP), which can significantly affect the ventilation system. The eight MWSs, which previously collected and stored temperature, barometric pressure and relative humidity data for subsequent NVP calculations, were upgraded to provide continuous real time data to the site-wide central monitoring system. These data can now be utilized by the ventilation engineer to create real time ventilation simulations and can indicate trends that assist in the prediction and mitigation of NVP and psychrometric related events.

Jan 1, 1999

By G. H. Roybal, J. M. Barker

Humate mining in New Mexico is a small industry [455 m3 (16,079 cu yd) valued at $395,894 for 1983] with three mines active in 1985. Either humate (carbonaceous claystones rich in organic matter) or weathered coal ("leonardite") high in humic acid are mined. The humic acid content needed to meet consumer specifications determines which type is mined. The humate and "leonardite" now mined in New Mexico are used primarily as soil conditioners or as drilling mud additives. The potential resource for both are very extensive within the coal-bearing formations of the San Juan Basin in northwest New Mexico.

Jan 1, 1987

By M. G. Ayat, B. C. Scott

J. Dasher Having an interest in coal slurry pipelines from a decade of arguments with Ed Wasp and crew at Bechtel about pumping thicker slurries slower, I immediately read this article and found nothing in it pertinant to the title. Ayat and Scott pumped five unidentified coals at 9% solids (50%-60% is the area of interest) in a 25-mm (1-in.) pipe around two square elbows through a 76-mm (3-in.) cyclone for up to 60 minutes and sized a large number of samples of unstated size on an unidentified wet screening device. They did not measure power consumption, discharge pressure, flow rate, or give pump tip speed or impeller diameter. They siad the cyclone had a "high" pressure drop (unmeasured) and did much of the degradation (measured) but more or less per unit of energy expended? Hargrove was not measured, so there are no data as to whether it would correlate with degradation. The authors conclude, with no attempt, correlation is "hard to establish." Please experiment before concluding. I am at a loss to know what "increasingly smaller size" means, much less what theory says such particles take "exponentially larger quantities of energy," which the authors neglected to measure. If such experiments without pertinent data or justified conclusions must be published, please attach a pertinant title. reply by M. G. Ayat The first and the last criticism of this paper is that the work is not pertinent to the title. Anybody who reads this article will immediately realize that the work describes the breakage of coal particles to finer sizes in coal slurry pipes and pumps. If this is so, why not title the work "Degradation process in coal slurry pipelines"? What could be more pertinent to this title than the investigation concerning the degradation phenomenon of coal particles in a pipe carrying a coal slurry? Mr. Dasher complains that he does not understand the meaning of the term "increasingly smaller size." The first sentence of this article defines the degradation process as "the breakage of coal particles to increasingly finer sizes." The term "increasingly finer sizes" here means successive breakage of a fine particle to finer and finer sizes. According to Hukki (Hukki, 1975), the probability of breakage is high for large particles and rapidly diminished for fine sizes. We apologize for being brief about some of these definitions. The degradation process, breakage of particles to increasingly finer sizes, is so widespread in the mineral industry that we did not feel it necessary to bore the reader with lengthy definitions of some simple terms. Mr. Dasher states that the coals examined and their original size consist are unidentified. Please look at Table I and Table 2 in the paper again where you will find the original size consist of the coals examined and their full specifications. We only named the coals A, B, C, D, and E to avoid identifying the coal seams that were more susceptible to degradation. Not identifying the name of the wet screening device used in this work has also been criticized. In our opinion, wet screening operation is such a routine and standard procedure that naming the device by which the screening is performed would serve no purpose but to promote a sales approach. This was not our intention. We did not conclude that the correlation between the degradation process and Hardgrove Grindability Index is hard to establish as Mr. Dasher writes in his letter. We stated, not concluded, that "It is reasonable to assume that some relationship between the extent of degradation and its physical properties, such as Hardgrove Grindability Index, does exist. However, any definite correlation is difficult to establish." This statement is based on other researchers work, which are clearly referenced in the article. The conclusions of this paper were based solely on the findings of the experimental work. As for the theory of comminution that Mr. Dasher asks, we would like to refer him to some basic comminution books and articles where various theories are clearly described. For example, Hukki (Hukki, R.T.,"The Principles of Comminution; An Analytical Summary," Eng. Min. 176, 106, 1975) suggests that the relationship between energy and particle size is a composite form of three laws (Bond's law, Kick's law, and Rittinger's law). A comprehensive analysis of coal breakage processes is also performed by Broadbent and Callcott (S.R. Broadbent, and T.G. Callcott, "Coal Breakage Processes, I. - A New Analysis of Coal Breakage Processes;" and "Coal Breakage Processes, II. - A Matrix Representation of Breakage," Journal of the Institute of Fuel, pp. 524-539, December 1956). These and many other relevant publications explain the relationship between the particle size and energy much better that what can be said in this short reply. We will, however, agree with Mr. Dasher on one particular point. We, too, believe that if the investigation concerning the degradation process in coal slurry pipeline were to be pursued further, one could choose to determine one or more of the variables available in the process, such as discharge pressure, power consumption, percent solid, pipe diameter, etc.

Jan 1, 1989

By M. Rossi

The use of service variables in geostatistics (grade-thickness) is common in industry when developing block grade models and geologic resource estimates. This is particularly true in the case of sedimentary and stratabound-type deposits. The approach has proven merits when assessing ore reserves. However, there are cases where its application for preliminary data analysis produces biased estimates. One such case is encountered in uranium disequilibrium studies. This paper demonstrates the inadequacy of service variables when performing uranium disequilibrium studies. Disequilibrium analysis is a necessary preprocessing step when radiation counts are used as raw data to calculate uranium reserves. Typically, a probe is used to obtain the gamma counts from open drill holes. These counts are then regressed (and corrected) against chemical assays obtained from core samples. During this process the grade-thickness variable produces an optimistic image of the relationship between probe grades and chemical (true) grades, causing overestimation of the final geologic resource. The problem is analyzed through a case study.

Jan 1, 1993

By Steven J. Van Kauwenbergh, Talaat A. B. Lawendy

Batch laboratory-scale beneficiation tests were conducted on four high-iron phosphate samples. These samples included sedimentary ores (Tilemsi Valley, Mali and Tahoua, Niger), a sample from an igneous phosphate deposit (Matongo, Burundi), and a fine-grained phosphatic iron ore processing residue from Chile. The Matongo phosphate deposit occurs as a thick (up to 80 m) residual blanket of P205-enriched soil over solid parent rock (carbonatite and associated rock types). Although the Matongo deposit is an igneous deposit, ore from the deposit can be subjected to beneficiation treatments commonly used to treat sedimentary rocks. The beneficiation flowsheets designed to process these diverse ore types involve attrition scrubbing, size classification, and flotation. At the best flotation conditions tested, phosphate concentrates assaying 32.0%-39.0% P205 and 1.0%-1.5% Fe2O3, were obtained at 64.2%-82.2% overall P2O5 recoveries from run-of-mine (ROM) ores containing 9.2%-28.6% P205 and 5.9%-16.1% F,20,. A cleaner phosphate concentrate assaying 33.1% P205, 1.8% A1203, and 3.3% Fe2O3 at 53.4% overall P205 recovery was obtained from the phosphatic iron ore residue that originally contained 4.5% P205, 8.0% A1203, and 17.6% Fe2O3.

Jan 1, 1993

By Henry N. McCarl, Gary Waters, William A. Vogely

INTRODUCTION In the past three decades, world trade has grown from less than $100 billion per year in the years following World War 11 to slightly more than $300 billion in 1970 and over $2,000 billion in the early 1980s. Adjusted for inflation, the real growth of world trade in 1972 dollars increased from less than $175 billion per year in the early 1950s to slightly more than $342 billion in 1970 and almost $700 billion per year by the early 1980s. Thus trade as a whole has increased a little more than twofold in real terms in the past decade." Mineral commodities constituted approximately 20% of the value of total world trade in 1970, and significantly more than that proportion in terms of physical volume. By 1980, de- spite rapidly rising petroleum prices, mineral commodities accounted for roughly 18% of the total value of world trade. Crude oil alone ac- counted for about 16%, making it the single most important commodity in international trade. The worldwide recession of 198 1- 1983 brought a dramatic decline in both volume and price of crude oil, shrinking the impact of mineral commodities to roughly 10% of the value of total exports, worldwide, in 1982- 1983. The decline of mineral commodities as a pro- portion of the value of world trade in the decade 1970- 1980 is due largely to the increasing importance of manufactured goods and consumer products such as automobiles and electronic items. During this period, mineral commodity trade expanded roughly sixfold in terms of current dollars to an estimated $350 to 360 billion in 1980. This was equivalent to doubling the real value of mineral commodities in international trade in the 1970- 1980 period in constant dollars. The U.S. Bureau of Mines has expanded the traditional definition of mineral commodities to include semifinished products such as iron and steel (in addition to iron ore), refined metals such as copper, lead, zinc, aluminum, and tin, concentrates, scrap, and petroleum products. Since large quantities of essentially mineral derivatives travel in this form, it is reasonable to use these expanded definitions in stating the role of minerals in world trade. Thus minerals in world trade comprise 30 to 33% of total export trade in all commodities during the period 1976- 1980 (see Table 1.3.1). In addition, the U.S. Bureau of Mines estimates the value of all mineral commodities consumed in the world (at the national level) and compares this value to total worldwide commodity consumption. By this system, mineral commodities range from 30 to 40% of all commodities consumed each year in all countries during the period 1976- 1980 (see Table 1.3.2). The growth in export trade in mineral commodities by commodity group is shown for the period 1976-1980 in Table 1.3.3. These data parallel the swings in worldwide economic activity during the same time period. By any of the above measures, minerals, especially the fossil fuels, constitute a significant proportion of both total economic activity and

Jan 1, 1985

By Jon Y. Kaneshiro, Gregory E. Korbin, Stephen J. Navin, Larry J. Stout

Sewage presently being discharged into the Tijuana River Valley pollutes the valley as well as the beaches in the South Bay of San Diego, making the beaches unusable nearly year round. The SBTO will convey flows down a 8.5 m (28 ft.) by 58 m (190 ft.) deep drop shaft, through a 3.35 m (11 ft.) by 5.8 km (3.6 mile) long tunnel, and up a 46 m by 2.7 m (150 ft. by 9 ft.) riser shaft connecting to a 1.5 km (0.95 mile) of seafloor pipeline and 1.2 km (0.76 mile) of diffusers on the ocean floor. The drop shaft will be sunk through 38 m (125 ft.) of saturated sands and gravels and 20 m (65 ft.) into the dense fine sands of the San Diego Formation. The tunnel liner has been designed as a five piece, single pass, gasketed, bolted, reinforced concrete liner designed to withstand an external head of 76 m (250 ft.) of water and internal operating head of up to 27 m (89 ft.) and to accommodate movement at the numerous fault crossings. The tunnel is contemplated to be driven with a state-of-the-art Earth Pressure Balance Machine (EPBM) or slurry shield machine through a wide range of conditions from clay to gravel with boulders.

Jan 1, 1995