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The purpose of this paper is to present validation studies of the mine-fire simulator using data gathered from an actual mine fire which occurred in November 1991 at the Pattiki Mine. To develop the model of the ventilation system with the fire in this validation study, the following adjustments were made: (1) flow and gas distribution in the entire ventilation network, and (2) fire parameters matching the data recorded by the monitoring system. After close correlations between simulation and real data were achieved, additional analysis of the ventilation system with the mine fire was performed. Presented and discussed in this paper are the following stages of the fire at the Pattiki Mine: (1) early fire (before the fire was detected), (2) preparation for and fire fighting with water, (3) fire sealing, and (4) fire extinguishing. This study evaluates the suitability of the computer software package for modeling underground fires. The paper also discusses the importance of the on-line monitoring system for the validation process.

Jan 1, 1995

By Lauren W. Choate

Wollastonite, a calcium metasilicate, derives its name from the man who discovered the mineral, Doctor William H. Wollaston, an English scientist. OCCURENCE Occurences of the mineral have been noted in Finland, Switzerland, Russia, Japan, Mexico and in the United States in Texas, California, Arizona, and New York. The only commercial deposit now being exploited is at Willsboro, New York. It is mined and processed by the Cabot Corporation whose home offices are in Boston, Massachusetts.

Jan 1, 1964

By M. Scaggs

"Respirable dust in underground coal mines has long been associated with lung diseases, and regular dust sampling is required for assessing occupational exposures. At present, respirable dust concentration and crystalline silica content are commonly determined, but considering recent and yet unexplained increases in the incidence of lung disease amongst miners in specific geographic regions, more information about specific dust characteristics is urgently needed. While particle-level dust analysis is ideal, it is impractical for large numbers of dust samples because it is both time and cost intensive. Thermogravimetric analysis (TGA), however, is an alternative option, which offers the ability to determine the total coal to mineral mass ratio in a dust sample – analogous to proximate analysis of bulk coal samples for determining ash content. Here, preliminary development of a TGA method for this purpose is presented. The method is being developed to evaluate dust collected on mixed cellulose ester (MCE) filters using approved permissible sampling equipment. INTRODUCTION Based on the particle size, airborne mine dust can be classified in three categories: inhalable dust (< 100 µm in size), thoracic dust (< 25 µm in size), and respirable dust (< 5 µm in size) (Ramani et al., 2003). The World Health Organization (WHO, 1999) defines inhalable dust particles as those which can be breathed into the nose and mouth, and thoracic dust particles as those which can penetrate airways of the head and enter the airways of the lung. On the other hand, respirable dust particles can penetrate beyond the terminal bronchioles into the gas-exchange regions (alveoli) of the lungs (WHO, 1999). Hlavay (1992) reported that the seriousness of the damage in the lungs and respiratory tract is based on amount of dust remaining in these organs, and the amount of dust depends on the extent of dust exposure, the size distribution of the dust particles, and the capability of the body for dust elimination. Inhalation of respirable coal dust by miners can cause a disabling and potentially fatal lung disease which is called coal worker’s pneumoconiosis (CWP). Silicosis is another fatal lung disease caused by inhalation of respirable silica dust. In CWP and silicosis, dust particles deposit in the lungs, damage the lung tissue, and ultimately cause scarring which cannot be reversed (Colinet, 2010). While overall incidence occupation-related lung disease amongst coal miners in the US has been declining for over 40 years, it appears that there has been a recent increase in specific locations in Central Appalachia (CDC, 2006; Pollock et al. 2010; Suarthana et al., 2011). Although this trend is yet unexplained, one theory is that particular dust characteristics in these locations may be a factor (Hassan and Lau; Page & Oraniscak 2002). For example, several studies have indicated that different coals may generate different amounts of respirable dust (e.g., see Page, 1993 and Litton and Page, 1994), and the surrounding geology may also play a role in terms of the types of dust particles generated. Although respirable dust concentration and crystalline silica content are commonly determined as part of regulatory compliance sampling, more information about specific dust characteristics (e.g., size, shape and composition) is urgently needed."

Jan 1, 2015

By Kim A. Lapakko, William W. III White

The ASTM standard method D 5744-96 was developed to provide a well-defined kinetic test protocol, conducted under controlled reaction conditions, with the intent of generating reproducible results. The US Bureau of Land Management, American Assay Laboratories, and the Minnesota Department of Natural Resources cooperated in a intralaboratory and interlaboratory testing of the protocol. Intralaboratory testing was conducted on duplicate samples of gabbro (8) and siltite-argillite (5) rocks for periods of 20 to 125 weeks. The difference between replica& intralaboratory pH readings on drainage from the gabbro for the drip-trickle leach alternative typically did not exceed 0.1 units, although differences as high as 0.4 units were observed. The difference from the mean for rates of sulfate, calcium and magnesium release was typically within 10%. Intralaboratory results for the siltite-argillite samples were generally similar, although a one unit pH difference was observed for one sample. Three different laboratories tested a gabbro sample for 125 weeks, with a maximum difference from the mean pH of 0.5 units. The percent difference from the mean for sulfate and calcium release rates was typically within lo%, although values as high as 30% were observed. Data on intralaboratory and interlaboratory agreement on the flood rinse alternative of the method were limited. Replication on the sample tested was comparable to of better than that observed for the drip-trickle method testing of the same sample.

Jan 1, 2000

By Eduardo Velasco, Paz Navarro, Alfonso Navarro, Claudio Cimiotti, Alejandro Sanz, Nick Karlin

The LA Effluent Outfall tunnel is a 7-mile long, 18' internal diameter, secondary treated effluent discharge tunnel currently under construction by Dragados USA for the Los Angeles County Sanitation District No. 2 (LACSD). The purpose of this tunnel is to add redundancy and increased capacity for discharge of secondary treated effluent from the LACSD’s Joint Water Pollution Control Plant, located in Wilmington, California within Southern Los Angeles County. Current discharge from this facility flows through two existing tunnels of 8' and 12' horseshoe profile, constructed in 1937 and 1958, respectively. When the new tunnel is complete, it will add an additional capacity of 670MGD in peak wet weather flow conditions. Geology of the roughly 7 mile long tunnel was divided into six reaches by the contract documents. Tunnel Reaches (TR) 1 to 3, comprising 19,550' will be excavated in alluvial sands of the San Pedro and Lakewood formations, with cover ranging from 45 to 90 feet. In this reach the tunnel intersects the seismically active Palos Verdes fault Zone. TR 4 is a 1,600' transitional zone between alluvium and the rock formations of the Palos Verdes (PV) Hills, comprised mostly of Malaga Mudstone. TR’s 5 and 6 total 15,591', and are within the rock formations of the PV Hills with overburden ranging from 315' to 475'. The primary constituent of the PV Hills is Altamira

Jun 13, 2021

By E. B. Thorn

The production of portland cement requires that four basic elements -- calcium, silica, alumina and iron -- be ground to a fine powder, homogenized, and fed to the pyroprocessing unit, where it is burned to a cement clinker. The raw material must either be ground wet in a slurry form or dried and ground to a dry powder, with a fineness of approximately 85% passing the 200 M screen. According to the Portland Association&apos;s Plant Information Summary, approximately 38% of the U.S. capacity is ground wet and 62% ground dry. The following data is taken from the Portland Cement Association&apos;s 1981 Energy Survey: [Million BTU/Ton kW h/Ton Wet Process Plants 5.86 138 Long Dry Process Plants 4.97 123 Dry Preheater Plants 4.03 157 ]

Jan 1, 1984

By W. J. Miles

Oil based drilling fluids utilize a number of industrial mineral products to accomplish oil and gas drilling in several environments where water based drilling fluids are less effective or inappropriate. These industrial minerals include: organically modified bentonite, organically modified lignite, barite, hematite, mica, calcium chloride and other salts. A variety of organic products are also utilized in oil based drilling fluid formulations. Oil based drilling fluids are preferred in several drilling situations because: they can be used to drill through water sensitive formations; they produce holes that are very close to the drill bit gauge; they exhibit high temperature stability; they are more environmentally acceptable; they minimize producing formation damage; they provide faster drilling rates when used with new polycrystalline diamond drill bits; they minimize pipe sticking and lost rig time.

Jan 1, 1986

By R. Gorakhki, R. Stafford, A. Jung

Geosynthetic clay liners (GCLs) have been used widely as an alternative for compacted clay liners and covers in mine waste applications. The high swelling of bentonite particles in the GCL creates a uniform barrier layer that results in low permeability of water and mine waste leachate. GCLs must provide sufficient internal and interface shear strength stability, especially if GCLs are used in steep slopes under high normal loads. Peel strength is a common parameter that is typically correlated to internal shear strength properties of GCLs. The relationship between internal shear strength and peel strength of GCL at normal stresses of 287, 575, 862, and 1724 kPa is evaluated in this study. The data in this study was compared with the peel strength-internal shear strength relationships found in literature. The study concludes that the relationship between peel strength and internal shear strength is unique based on manufacturing, needle-punching density and the method with and without heat treatment of the geotextile end fiber bundles.

Feb 1, 2023

By C. Haycocks

The evolution of longwall mining is briefly traced from its inception in England in the 1620&apos;s. In the beginning this method recovered 90% of coal with roof closure controlled by packs and walls. Mechanization began with kerf cutting, crude face conveyors, and improved face support. Full face mining was accompanied by the introduction of self-advancing hydraulic supports. U.S. longwalls evolved a retreating system to recover blocks of coal outlined by room and pillar panels. Computer control combined with the most modern technology has greatly increased productivity. Past trends are used to predict future technological directions.

Jan 1, 1997

Dynamic permeability is a significant hydrologic condition associated with in-situ leaching at the Cyprus Casa Grande operations. Several factors contribute to changes in the permeability conditions. They are: 1) hydraulically induced fracture development, 2) geochemical changes during leaching in the rock matrix, and 3) changes in the relative degree of saturation of the deposit. Dynamic permeability conditions were evaluated using available pressure and flow rates from the 58 injection and recovery wells obtained over one year period. A finite element, 2-D hydrologic model called INVERT which is designed to estimate aquifer parameters under transient and steady state flow conditions was used for the investigation. The permeability conditions during 7 different steady state intervals throughout the one year time frame were determined. The results confirm that big changes in permeability occur as a function of time as well as a function of injection pressure condition.

Jan 1, 1991

By C. Hosten

This paper presents the results from an extensive research program on the vacuum filtration of iron ore slurries. Experiments were conducted with the addition of several types of flocculants and surfactants. The filtration response of the slurries was studied in terms of the cake formation rate and the residual cake moisture. An analysis of the results is presented in ascertaining the role of flocculants and surfactants during filtration

Jan 1, 1983

By Madan M. Singh

Although roof bolting has been a major means of strata support for nearly two decades, little attention has been directed towards the design of bolt Installations. The variables involved are interdependent and their study complex. However, some simple tests may be employed to serve as guides to the efficient design of roof bolt systems. Local conditions are continually varying and are important to pattern design. This paper discusses such considerations and suggests techniques which may be employed to effect improved roof control with bolts.

Jan 1, 1967

By J. van Oldenborgh

The world market for bunkers represents some 140 MT (1980) of marine fuel oil and distillates. This is equivalent to 23CMT of coal, a potential market for steam coal larger than the total seaborne trade of steam and metallurgical coal today, and an obvious area which could contribute savings in world oil consumption. Oil bunkers are lifted fairly evenly throughout the world, the main supplying regions being Western Europe, the Middle East, North and Central America and Japan (Figure 1). Not surprisingly, the main customers are the tankers representing about 50 percent of the world market - (95 percent of the Middle East Market) - dry bulkers represent some 30 percent and general cargo ships the rest.

Jan 1, 1982

By B. Mishra, Q. Shi, Y. Zhao, G. Zhao

Shale is anisotropic due to the presence of bedding planes. The anisotropic strength of shale has been extensively studied. However, little attention has been paid to the size effect on shale strength considering the anisotropy. This research uses the discrete element method to study the size effect on the strength of shale under the uniaxial stress state. It is assumed that the anisotropy is caused by bedding planes, while the size effect is caused by randomly distributed flaws. The numerical model of shale comprises three components: shale matrix modeled by bonded particles (2) bedding planes modeled by smooth joints (3) flaws modeled by discrete fractures. The developed model is scaled to different sizes and tested in the uniaxial compression and the direct tension tests. The test result show that the uniaxial compressive strength decreases as the specimen size increases when the loading direction is perpendicular or parallel to bedding planes. The uniaxial compressive strength is determined by the flaws while the bedding planes only play a limited role. However, the size effect on the direct tensile strength depends on the direction of bedding planes. When the loading is perpendicular to bedding planes, the size effect is not prominent. The direct tensile strength is determined by the bedding planes while the flaws have little effect. When the loading direction is parallel to bedding planes, the direct tensile strength decreases when the specimen size increases. The direct tensile strength is determined by the flaws while the bedding planes have little effect.

Mar 2, 2022

By G. H. Friedrich

The distribution of mercury in soils, rocks, and ore was studied in three areas of the Pachuca-Real del Monte District: (1) An area north of the town of Pachuca where ore veins have been found at or near the surface. The mercury content of soil samples taken near the vein zones is far above the background value. The highest value was 1900 ppb (parts per billion) mercury in a soil sample above Veta Vizcaina; the background is about 50 ppb Hg. (2) In the area north of the town of Real del Monte where only a few of the veins are known to crop-out. Regardless of exposure, soils collected over veins show anomalous mercury values ranging from 250 ppb to 1900 ppb. (3) In an area south of the town of Real del Monte. Here, although vein outcrops are lacking, mineralization is known at a depth of about 120 m. All soil samples taken at 50 m. intervals along an east-west traverse contain anomalous amounts of mercury, with peaks corresponding with the known location of the veins.

Jan 1, 1965

By Mark E. Emerson

Foreign and domestic companies find the mineral potential of this country&apos;s stern public lands, its capital markets, political stability, and "open-door" policy attractive for hard mineral exploration. Traditionally, exploration in the US has been geographically based and responsibility oriented at the district level. The 1970s brought a decentralized approach to exploration as major non-metal companies began to diversify into hard minerals. The emphasis was on capital intensive metal and energy projects involving bulk-tonnages. The recent economic downturn in metals has caused many of the new participants to withdraw from the mineral scene. The surviving companies have shifted their emphasis toward medium scale precious metal projects having high operating margins and rapid return on equity. Exploration expenditures in the United States are now principally focused on gold and silver to the exclusion of practically all other commodities. In the search for precious metals companies have scaled back their exploration efforts and have began to apply new approaches to target selection. The search is being assisted by rapidly evolving conceptual models. The change in orientation has led to numerous new discoveries. The finds are essentially "rediscoveries" that c,-re previously uneconomic. The majority are low-grade surface deposits that have involved low discovery costs and short lead times for development by low-cost mining and beneficiation methods. The emphasis on gold to the exclusion of all other commodities raises questions regarding the direction of exploration in the US for the rest of the 80s.

Jan 1, 1984

By Jerry G. Rose

This paper addresses a process by which both the disposal and utilization of preparation plant coal refuse can be simultaneously accomplished with an attendant benefit of significantly increasing the percentage of extractable coal. A laboratory study is described in which coal refuse was successfully utilized as an aggregate in low cost concrete (coal-crete) mixes under simulated mine environments. Coal-crete specimens with compressive strengths of 14,000 kPa (2,000 psi) were consistently produced. A construction sequence and mining plans are offered for placing the low-cost coal-crete pillars in accessible areas in room-and-pillar mines so that a Substantial portion of the remaining coal pillars could be extracted. The method could be applicable in areas where mining procedures do not permit pillar extraction because of possible surface subsidence, roof problems, or other conditions. Possible structural difficulties with the coal-crete pillar support system are discussed. Using a discounted cash flow analysis, the economic feasibility of mining with the coal-crete pillar system is investigated. The cost of the coal-crete pillar system is compared to the cost of a mining system which would have less coal recovery. The analysis indicates that although at higher coal selling prices the coal-crete mining system may yield an acceptable rate of return, the alternative of leaving the coal pillars is more attractive at the present time.

Jan 1, 1977

By John E. Butler

Due to the present economic climate, particularly the depressed copper market, conventional mining, milling and flotation operations have been suspended. However, due to the apparent amenability of the ore to &apos;natural&apos; leaching, investigations have been initiated into establishing an in-situ leaching operation as a preferred alternative to conventional operations. Cement copper production has been developed in parallel with the leaching trials and is presently at the rate of approximately 3,000 tonnes of contained copper per annum. Testwork includes controlled leaching of ore both in the laboratory and in-situ following blasting.

Jan 1, 1981

By C. E. Capes

The continuous balling? operation whereby a moist particulate mass is tumbled in a horizontal revolving drum with recirculation of the undersize product can be extremely unstable. Product and recycle rates are subject to wide fluctuations. Although the problem seems to be well-recognized, there is little published information or quantitative data readily available, especially in relation to industrial-scale circuits. Probably the best available published results are in the Russian literature, an illustration of which is given in Figure 1. These data, taken from a study&apos;) of some of the factors which influence the stabilization of the pelletizing process, illustrate the wide variations in circulating load and circuit productivity which may be encountered over a period of operation. The problems of balling circuit stability may be traced to random seed or nuclei generation and uncontrolled agglomerate growth. The situation is analogous to that in crystallization processes where (4 considerable attention is given to nucleation control. Traditionally attempts have been made to optimize system and operating variables to stabilize the balling process. A supplemental approach which is taken here is to build on the considerable

Jan 1, 1975

By L. Xiao

Using K-oleate as a collector and alizarin red S (ARS) as a modifying agent, selective depression of dolomite from francolite was achieved in alkaline medium (pH> 9.0). Interestingly. ARS was also found to depress igneous apatite in alkaline medium in oleate flotation of apatite and calcite. Adsorption of ARS alone on dolomite was found to be higher than that on francolite. Complimentary adsorption experiments of ARS and K-oleate showed that oleate adsorption was increased in the presence of ARS on francolite but not on dolomite. K-oleate adsorbs on both francolite and dolomite and causes precipitation of calcium and magnesium oleate. Such precipitates can be pre-vented when ARS is present. The results are explained in terms of competitive adsorption for the active sites on francolite and dolomite by oleate and ARS, and their interactions with dis-solved mineral species in solution.

Jan 1, 1988