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By R-H Yoon

The thin film pressure balance (TFPB) technique was used to measure the kinetics of thinning of single foam films and disjoining pressures in the presence of sodium dodecyl sulfate (SDS) and electrolyte (NaCl). The results were analysed in view of the Reynolds equation to determine the role of surface forces in film thinning. It was found that film thinning is controlled by surface forces at thicknesses below approximately 200 nm. It was also found that hydrophobic force plays an important role particularly at low SDS and NaCl concentrations. The values of the hydrophobic force constant (K232) estimated from the film thinning experiments were used to predict the disjoining pressure isotherm using the extended DLVO theory, which were found to be in excellent agreement with experiment. The TFPB technique was also used to measure the equilibrium thicknesses (He) of the foam films stabilised by a non-ionic surfactant, n-octanol, in the presence of NaCl. At a given ionic strength, He increased noticeably with increasing octanol concentration at very low concentrations. This observation suggests that hydrophobic force is at its maximum level in the absence of surfactant and decreases with increasing surfactant concentration. The results obtained with the single foam films were used to explain the stability of the three-dimensional foams.

Jan 1, 2005

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3 Mt of coking coal annually. The mine ventilation system currently utilises two 630 kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By K B. Holm

This paper deals with the advances made at Syferfontein Colliery in the calculation and control of dragline methodology. The high capital outlay and operating cost of a dragline necessitates strict control of all aspects of the dragline operation. Before purchasing a dragline, a complete evaluation of all the parameters that can affect the viability, now and in the future, of the dragline operation needs to be completed. Such parameters as thickness of burden, material properties (swell), “castability”, pit width and pit length, etc. need to be considered.

Jan 1, 1994

By D K. Weatherley, G R. Ballantyne, S Ali, M Yahyaei, M S. Powell

This paper explores development of a novel ore characterisation method for the precise measurement of practical minimum comminution energy. A monolayer of particles with a narrow size distribution is broken using a precision rolls crusher (PRC); an ore characterisation device developed to overcome the shortcomings of conventional tests. For energy measurement, PRC uses two shaftmounted rotary torque transducers. These transducers acquire precise torque and angular speed data in response to the load applied to the rotating shafts during breakage events, which is converted into energy. The test progressively crushes feed particles down to final product size in many controlled breakage stages. The generation of fines in each breakage stage is then plotted as a function of input energy. The inverse of the gradient of this plot provides the size specific energy (SSE) in kWh/t of material generated below a predefined marker size; -75 μm in this case. The PRC has potential to evolve as a geometallurgical ore characterisation test—it is simple, fast, requires small sample mass (200–300 g), covers a wide feed particle size range (10 mm to 115 µm), and provides ideal SSE measurements that can be used for the calibration of on-site production equipment.

Aug 24, 2022

By Pramod C. Thakur

In This Chapter [Origins of coalbed methane Reservoir properties of coal seams Thresholds for coal seam degasification Methane emissions in mines Methane drainage techniques How to transport gas safely in mine pipelines and Economics of coal seam degasification Recommended publications on coal seam degasification are Gas Control in Underground Coal Mining [Creedy et al. 1997], Coalbed Methane Extraction [Davidson et al. 1995], and Methane Control for Underground Coal Mines [Diamond 1994].] ORIGINS OF COALBED METHANE AND RESERVOIR PROPERTIES OF COAL SEAMS Origins of coalbed methane. Coal seams form over millions of years by the biochemical decay and metamorphic transformation of plant materials. This coalification process produces large quantities of byproduct gases, such as methane and carbon dioxide. The amount of these byproducts increases with the rank of coal. It is the highest for anthracite, where for every ton of coal nearly 1,900 lb of water, 2,420 lb (20,000 ft3) of carbon dioxide, and 1,186 lb (27,000 ft3) of methane are produced [Hargraves 1973]. Most of these gases escape to the atmosphere during the coalification process, but a small fraction is retained in the coal. The amount of gas retained in the coal depends on a number of factors, such as the rank of coal, the depth of burial, the type of rock in the immediate roof and floor, local geologic anomalies, and the tectonic pressures and temperatures prevalent at that time. The gases are contained under pressure and mainly adsorbed on the surface of the coal matrix, but a small fraction of gases is also present in the fracture net-work of the coal. Methane is the major component of gases in coal, comprising 80%–90% or more of the total gas volume. The balance is made up of ethane, propane, butane, carbon dioxide, hydrogen, oxygen, and argon.

Jan 6, 2006

By G. H. Glos

There was a time when an occasional failure of a tailings embankment was considered an acceptable risk associated with mining activities. This is not the case anymore. A major tailings failure today could result in the indictment of mine officials, huge fines and a possible site closure due to the loss of operating permits. As a result of this changed operational environment, tailings disposal facilities must be operated with these potential consequences in mind. Physical controls for tailings embankments are prohibitively expensive. However, the nuclear industry has developed a system of administrative controls as an alternative to physical controls. Administrative controls may be defined as control of actions, through organizations and management, using written procedures, record keeping, review and audit to assure operation of a facility in a safe manner (10 CFR 50). Administrative controls can reduce the cost of operating tailings impoundments, as well as increase the level of confidence in these facilities.

Jan 1, 1999

By Tony A. Rorke, Joe R. Brinkmann

The application of instrumentation to better understand and improve production blasting is one of the most fruitful areas of explosives and blasting research. The majority of instrumented studies of production blasting have relied on the extrapolation of far field measurements to postulate blast performance in regions of interest closer to the charge where rock breaking takes place. However, the nonlinear and dissipative nature of the quantities being measured raises serious questions as to the accuracy and validity of such extrapolations.

Jan 1, 1991

By Staff

The mineral sector is a fundamental part of the U.S. economy. It contributes to the real gross domestic product (GDP) at several stages—basic (mining), intermediate processing, manufacturing of finished goods and construction. The estimated growth rate for the real GDP of the United States for 2006 was 3.2 percent. The nominal GDP was about $13.2 trillion. The value of minerals mined in the United States in 2006 rose significantly because of increased unit price for some metals—particularly copper, zinc and other base metals. There was also a significant reduction in metals stocks. Infrastructure expansion and manufacturing in China and India have been absorbing a significant portion of world output. Domestic production increased for some industrial mineral materials, mainly cement and construction sand and gravel. Production of crushed stone declined less than 1 percent in 2006 compared

Jan 1, 2007

global mining boom and in-creased demand for iron ore has lead to a resurgence in the mining industry in Minnesota. At the combined 81st Annual Minnesota Section of SME Meeting and 69th Annual University of Minnesota Mining Symposium, April 15-16 in Duluth, MN, this resurgence was the hot topic as new mining projects were featured in the keynote session. The meeting attracted more than 400 mining industry professionals, including engineers, executives, mining managers and suppliers from around the world. This year?s theme was ?New Ventures in Mining.? The meeting included concurrent technical papers sessions, a keynote session that featured three distinguished speakers and a panel discussion that provided updates on new mining developments in the state. The Minnesota Section of SME technical papers were presented in concurrent sessions, one on mining and one on mineral processing. The mining session included papers on drilling, ore blending, slope stabilization, dust control and operations management. The mineral processing session included papers on plant-control technology, ball mills, pellet strength and fans. Also offered was an SME short course titled ?Simulation based pellet induration optimization.? The Minnesota Section of SME held its annual business meeting during the conference. The 69th Annual University of Minnesota Mining Symposium technical sessions were held on April 15 and also consisted of concurrent sessions on mining and mineral processing. Mining session topics included logistics management, real-time performance measurement, uses for taconite aggregate and environmental issues. The mineral processing session included papers on ore liberation characteristics, zeta potential studies, induration modeling, fuel optimization and conveyor belts. The combined conference included a tradeshow with more than 80 booth spaces featuring vendors offering products and services to Minnesota?s booming mining industry. More than 900 people, including conference registrants and special invited guests of the vendors, at-tended the tradeshow opening reception. This was the largest trade show in many years ? an indication of the vitality of the mining industry in Minnesota.

Jan 1, 2008

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the ninth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township map. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By Lars Arne Granlund

Due to the coarse structure of mining explosives, one has to model a finite reaction zone,contrary to C-J calculations, describing their detonations, i.e they become dependent of diameter and confinement, An effort within the DYNO group has been to investigate if the DSD theory ( originally developed by Bdzil, Stewart / Los Alamos ) can be used to describe major groups of civil explosives.The groups of explosives tested are dynamite, anfo, aluminised emulsion, heavy anfo and straight emulsions.

Jan 1, 1995

By G Njowa

Mineral resource evaluation and estimation process is not an exact science; however it depends on the knowledge and experience of the competent person and his ability to apply his mind, make reasonable assumptions, interpretations and exercise sound judgment in the mineral resource estimation process. The mineral resource evaluation results in a mineral resource statement are disclosed to investors. The minerals industry is presently undergoing rapid changes in legislation governing the public reporting of mineral assets. It has gone through different phases of development with respect to the reporting of mineral resources and mineral reserves (mineral assets). In the past no reporting was done and currently mineral assets are reported as a supplementary section that briefly describes the mineral asset termed ?the mineral reserve and mineral resource statement?. The current industry trend appears to be going towards recognition and disclosure of the mineral assets on to the balance sheet. This paper explores the salient issues behind the mineral resources and mineral reserve statement of vein and reef deposits published in the public domain. It also highlights the potential misleading consequences of these issues and which filter through to the valuation of these particular mineral assets. The creation of reporting standards in the minerals industry has made significant inroads in standardizing and consolidating the interpretation and understanding of the different classification categories in the industry in an effort to promote common interpretation towards these salient issues.

Jan 1, 2008

By Chuanlin Fan

The process of flotation separation and recycling of spent potlining (SPL) was described. On the basis of the laboratory investigations, the effects of influencing factors in froth flotation process, such as grain size, flotation agent dosage, pH value, pulp density, and dissolved components concentration, etc, were carefully studied. And the influence on environment of the process was also discussed. It was found that flotation separation can be used as an environment-friendly method for treatment of SPL residue. Carbon and other compounds (include cryolite, sodium fluoride, calcium fluoride and diaoyudaonite, etc.) from SPL were separated and recycled as flotation products respectively.

Jan 1, 2009

By I T. Tshabalala

In typical conventional narrow vein stoping operations, the use of temporary support components to offer some support to workers, whilst the permanent and generally more elaborate support system gets installed or constructed, still results in injuries to people. The authors wishes to explore the probability and practicality of making use of new generation support products to make the support operations safer as well as enhance productivity in the stope face. This paper will examine the use of Autorock Drills as a means to drill roof support holes and install appropriate support components into these holes, as well as the application of ?Thin Spray Liners?, commonly called TSL?s as an additional means of creating a safer operating environment. The installation of netting as a means of roof protection and other support aspects such as cemented roof-bolts will also be explored. These proposed items are envisaged to improve the safety of our people and reduce production down time and increase production and productivity.

Jan 1, 2008

By Gary Kuhns

Central Florida is among the fastest growing urban areas in the United States, and its rapid development has required the steady construction of various types of civil engineering works. The karst geologic terrain and variable geotechnical conditions, however, present special challenges to the design and construction of deep foundations. The subsurface profile can be idealized as a surficial layer of Pleistocene sands, underlain by the highly variable Miocene-age Hawthorn Group, consisting of various combinations of sand, silt, clay, phosphate and highly weathered limestone. The Hawthorn Group is underlain by Eocene-age limestone that comprises the Floridan aquifer. Vast networks of solution cavities are present throughout the Eocene limestone, sometimes allowing downward raveling of the overlying soils and the creation of sinkholes. In some cases, the relic sinkholes can be filled with soft compressible organic soils extending to depths greater than 100 feet (30.5 m). Driven piles are frequently employed as a deep foundation alternative, although occasionally cast-in-place piles/shafts have also been used. Piles are often driven for bearing in the weathered limestone within the Hawthorn Group, but are sometimes installed as friction piles in the upper soil and intermediate geomaterials. Dynamic pile testing is routinely performed during pre-construction test pile programs, or during production for quality control and assurance purposes. This paper presents discussions on the design and construction aspects of deep foundations unique to Central Florida subsurface conditions and local practice. Foundation issues such as subsurface variability, soil setup, pile damage, negative skin friction, and sinkhole conditions are discussed with the aid of demonstrative case histories.

Jan 1, 2003

By E. G. King

Sodium-aluminum and calcium-aluminum silicates are important rock-forming minerals. While many of them are of only theoretical interest, several are of practical importance--as ceramic raw materials and as potential future sources of aluminum. Heretofore, thermodynamic data for these minerals were incomplete; and in many instances missing data were difficult to estimate reliably. This has seriously hampered thermodynamic calculations pertaining both to the natural formations of these minerals and to their decomposition in sintering and fluxing reactions. This paper reports the results of the Federal Bureau of Mines measurements of low-temperature heat capacities of four crystalline silicate minerals--dehydrated analcite (NaAlSi2O6), hexagonal anorthite (CaA12 Si208), lawsonite (Ca2Al2Si2080?2H20), and leonhardite (Ca2Al4Si8C24?7H2O). It augments previous similar measurements of related minerals, which were summarized recently.4 The measured heat-capacity data were used to derive entropy values for the four minerals at 298.15° K. Some relations between these entropy values and those of other similar minerals were discussed. These relations illustrate the difficulty of estimating entropy values of tertiary (or higher) silicates.

Jan 1, 1961

By F. Crundwell, A. J. Lathwood

A number of base-metal operations would like to increase production to take advantage of the higher metals prices. In general, this higher production should not be achieved with major operating changes. In hydrometallurgical facilities, leaching and pressure leaching represents one area where upfront limitations may be a bottleneck to the capacity of the entire plant. An assessment of the capacity of the leaching tanks and autoclaves was performed using a predictive model within the AweSym flowsheet simulator. The model is described, and the results of the application of the model to a number of different leaching reactors are presented. It is argued that the leaching number, which relates the residence time, particle size and the leaching rate, is of prime importance. Finally it is shown that there are some unexpected catastrophic events in increasing production capacity without a thorough understanding of the leaching operation.

Jan 1, 2007

By Dana C. Reinke, David K. I Ingram

Researchers at the National Institute for Occupational Safety and Health partnered with the water well industry to develop engi­neering control technologies and training products to address noise exposure at the job site. Noise­induced hearing loss continues to be a problem in the well drilling industry. Research con­ducted by NIOSH found that air rotary drill rigs produce sound levels more than 90 dB(A) over the course of an eight­hour workday. Sounds levels above 90 dB(A), identified during hammer drilling and the hammering of casing, exposes workers to levels that can damage hearing. A typical air rotary drill rig provides no barrier, for noise and dust pro­tection, between the drill’s control panel and the drill stem. The development of a partial cab is the clearest example of NIOSH’s research partnership with the water well industry. NIOSH researchers determined that an engineering noise control to protect the oper­ator at the rig’s control panel would be effective, based on typical work site conditions. Many surface rigs do not have full cabs as a result of the original equipment manufacturer design or the high cost of aftermarket products. Developed as a partial cab, the NIOSH engineer­ing noise control design addressed stakeholders’ needs associated with cost, transport, and worker usage (Figure 1). Field tests found the partial cab effective in reducing sound levels at the rig’s control panel, a typical location for a drill rig operator. Sound levels at the control panel were reduced from 104 to 96 dB(A) (Figure 2). Coupled with continued use of personal protective equipment, such as hear­ing protection devices, the partial cab can help to reduce noise exposure. NIOSH researchers created a CD with informa­tion about noise exposure and the partial cab. Most important to well drilling companies is information on how to construct and attach the partial cab to drill rigs. The CD can be viewed on a standard computer and includes a video of the partial cab in use on a work site. Computer­aided design drawings are included on the CD and provide detail of the cab design as well as information on construction mate­rials and design details. Additionally, the CD provides background infor­mation on noise­induced hearing loss and hearing protection devices to increase knowledge about this occupational health concern. This information can be viewed by all company employees to help promote the partial cab’s importance to workers using the cab. More information on the partial cab noise control technology can be downloaded from www.cdc.gov/ niosh/mining NIOSH researchers also examined the health and safety training needs of workers in the ground water industry. It was quickly realized that most workers learn health and safety on the job and do not attend any sort of formal training. In addition, there is not a lot of time for daily “tailgate talks” or “shop talks” on health and safety issues. As a small business industry, the owner is often operating a drill rig along with his other employees. In general, new employees learn the job in an apprentice style sys­tem. As a result, workers and owners have few opportunities to access uniform health and safety information based upon the job — an outdoor work environment with daily change in work sites. With this information, NIOSH researchers devel­oped two products that deliver health and safety information to fit into the daily work of well drillers. Both are information circulars and are available through download at www.cdc.gov/niosh/mining and the NGWA Web site at www.ngwa.org/publication/ publications.cfm. These circulars are: Water Well Safety Bits. This booklet provides information in a “quick bites” style. It is pre­sented in a magazine format and can be left on

By W. L. EGY, GEORGES. RICE, L. M. JONES, J. K. CLEMENT

This report has been prepared, not only for the purpose of recording the results of the first series of coal-dust tests conducted in the experimental mine of the Bureau of Mines, but also to place before the mining public a description of the mine and an account of the objects sought in its establishment. Soon after the organization of the technologic branch of the United States Geological Survey, J. A. Holmes, then chief of the branch, concluded that for the solution of various problems relating to the causes and prevention of mine explosions it would be best to carry on large-scale tests in a mine rather than in a surface gallery. The idea of utilizing the underground passage of a mine for making explosion experiments did not at' first meet with general approval among investigators in this country or abroad. Many thought a mine passage was not a proper place in which scientific tests could be conducted, as great difficulty in controlling conditions was expected. However, after all arguments for and against such an investigation had been carefully considered, plans for opening an experimental mine were definitely adopted by the Bureau of Mines in 1910, and an allotment of funds was made to carry out the project. The first endeavor was to find an existing mine suitable for the purpose, but the mines offered by owners were either worked out, were wet, had poor roofs, or presented complications of various kinds, so that it was finally decided to open a mine if a site could be obtained having natural conditions that would fill the various requirements. A most desirable location was found on property of the Pittsburgh Coal Co., near Bruceton, Pa. The president of this company, Mr. W. K. Field, the general manager, Mr. G. W. Schluederberg, and the chief engineer, Mr. E. J. Taylor, rendered every possible service in

Jan 1, 1913

By R. L. Montgomery

The heats of formation of lanthanum sulfate and the enneahydrate are -939.8 ± 3.1 and -1,587.1 ± 3.2 kcal. per mole, respectively. The heat of hydration is -32.5 ± 3.5 kca1. per mole. These values were obtained from heat-of-solution measurements of lanthanum oxide and salts. Low rates of solution precluded more accurate determinations of the thermal data. The heat of formation of the chloride was similarly observed to be -256.18 ± 0.28 kcal per mole. Heats of solution and combustion of lanthanum metal yield mutually concordant results, and earlier discrepancies reported in the literature may be ascribed to impurities.

Jan 1, 1959