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By Frank Cook

As in other areas of the country, surface coal mine productivity in the Central Coal Province--primarily Illinois, Indiana, and west Kentucky--has declined steadily since 1969 (figure 1). Productivity, as measured in tons of clean coal produced per man-shift, dropped 35 percent during the period 1969-1975. Unwelcome at any time, this phenomenon is particularly untimely now, when increased coal production is a national goal. The U.S. Bureau of Mines has been working with the coal industry to develop new operating methods and equipment to enable increased productivity and improved reclamation performance in surface coal mining. Several projects have involved identification and evaluation of existing overburden handling and reclamation practices, and development of means to improve operational procedures. Some results of one of those projects, as they apply to the Central Coal Province, are summarized in this paper.

Jan 1, 1977

By Dwight K. Smith

Fly ash as an additive for oil well cement was introduced to the oil industry by the Halliburton Company in 1949. Since its early usage in the Illinois area of the U. S., the total amount of fly ash pumped into wells has exceeded 30 million sacks, The advantages of using fly ash-portland cement mixtures in wells are fundamentally the same as for concrete except the conditions of placement and curing are variable and the nomenclature of properties are expressed somewhat differently. In some instances deep wells have been cemented with mixtures of fly ash and hydrated lime together with an activator which functions as a catalyst for setting. This fly ash-lime formula has many advantages for high temperature-pressure conditions found in wells.

Jan 1, 1968

By Kourosh Shahriar

The occurrence of rock falls in underground coal mines entails detrimental effects as fatal or non-fatal injuries on workers, stoppages in mining operations and breakdown of equipment. In this paper, a risk assessment approach on the basis of a decision analysis trend is employed in order to assess the possibility of and manage roof falls. Risk is then assessed by determination of likelihood of occurrence and the cost of consequences (outcomes). In this regard, collected real roof fall data from Tabas and Kerman coal regions comprising of several underground coal mines are used. It is concluded that the annual accidents due to the roof falls occurrence in the all investigated mines are so high that it is economically feasible to improve the support systems and to implement a suitable educational program as well as an accurate supervision and other elements of safety management.

Jan 1, 2009

By Feng Liu

"With seven new applications for plans of work for exploration in the international Seabed Area approved by the Council during its twentieth session of the International Seabed Authority, 26 total approvals have been made by the Council up to date. Among them, three contracts were made with COMRA. On 8 August 2014, China Minmetals Corporation submitted another application to the Authority for approval of a plan of work for exploration for polymetallic nodules in the Area, which is also sponsored by the Government of the People’s Republic of China.China is one of the main contributors to the international seabed regime. The Presentation will describe China’s activities in the Area, such as exploration, technology development, environmental protection and policy making.JIAOLONG is a submersible with capacity of 7000 meters. JIAOLONG’s sea trials were carefully made in 4 years, from 2009 through 2012 and it successfully dove to a depth of 7062m in June 2012 at Mariana trench. A so called "Test Application Phase" started thereafter, and is planned to last for 3-4 years. Two cruises and 4 legs have already been made since then. A wide-range of findings were obtained during dives in South China Sea, and in COMRA’s Exploration Contract Areas for polymetallic nodules and cobalt-rich ferromanganese crusts. This presentation will reveal the colorful findings."

Sep 1, 2014

By B. Swarbrick

Today’s mining occurs in a dynamic world of conflicting objectives. Mining companies have to look further than a traditional cash flow analysis to determine the potential value of developing a mine. In particular, proposals for new mine developments undergo rigorous scrutiny by a variety of stakeholders including regulators, NGO’s, and the local communities. From a business risk perspective, how mining companies address stakeholder concerns can have a dramatic impact on the success of the project. In today’s mining environment mining companies must continue to ‘walk the talk’ to stay in business, particularly during downturns in the business cycle. Falconbridge’s Raglan Mine is an example of a project that was successfully developed in a region that is sensitive from many perspectives, including environmental, socio economic, and regulatory. Close working relationships with local stakeholders along with strong environmental management systems are necessary elements of continued success for the project.

Jan 1, 2000

By William J. Halvorsen

We are currently doing work on three ways to improve the performance of our froth flotation systems. One development is the use of a cationic flocculent added to the feed of the froth cells. This does give some improvement in ash of the product particularly in a situation where there is a good bit of clay present. Difficulty is usually experienced with clay carrying over with the water contained in the froth product and also adhering to the coal surfaces. Addition of the flocculent to the flotation feed preferentially flocculates the clay causing it to drop into the tails. The results of some laboratory test work on Pittsburgh 88 Seam coal in Eastern Ohio is shown in Table 1. [ ]

Jan 1, 1979

By W. E. Threlkeld, J. A. Treacy, L. J. Stewart, J. C. Ruckmick

The Mustang Draw sulfur deposit is developed in a dolomite reef complex in the Permian San Andres Formation on the eastern margin of the Midland basin in Glasscock County, Texas. Interpretation of the genesis is dependent upon coincidence of a NE-trending fault system with the NW- trending reef complex. The reefs, reef talus, and oolites contained up to 30% interstitial anhydrite. It is indicated that artesian ground waters, hydrocarbons, and bacteria circulated into the reef complex along the fault zone. Bacterial consumption of hydrocarbons and anhydrite created extensive porosity, permeability, and deposition of sulfur in vugs and cavities, and along fractures in the dolomite.

Jan 1, 1992

By Kermit Allen

Storing natural gas in solution mined salt cavities appears to be one of the more promising methods being considered by some major gas transmission companies for meeting peak demands. Historically, these companies have been faced with the problem of meeting peak demands when the source of natural gas is located hundreds of miles from the marketing area. Transcontinental Gas Pipe Line Corporation's position was further complicated because some of its offshore Gulf Coast gas supply wells may have to be shut in during hurricane alerts. Transco's solution was to construct. solution mined salt storage caverns adjacent to its pipeline near Eminence, Mississippi. (See Figure 1.) In 1965, Fenix & Scisson, Inc., was engaged by Transco to evaluate the feasibility of storing natural gas in caverns dissolved from salt at selected locations along Transco's pipeline to the East Coast. In June of that year a report was submitted to Transco concluding that this proposal was feasible and recommending several potential sites for storage development. Additional engineering and geological studies followed and in March 1968 the Eminence Salt Dome site was selected and storage construction began that year.

Jan 1, 1971

By M. U. Khan

"Underground mine diesel equipment generally offers more flexibility as compared to electric powered systems. Diesel exhaust is an adverse agent which affects the health of underground miners. The National Institute of Occupational Safety and Health (NIOSH) regard diesel exhaust as carcinogenic. The NIOSH 5040 method is an established technique for measuring Diesel Particulate Matter (DPM). This process inherently involve a lag time before an accurate exposure determination can be made during which miners are potentially overexposed to DPM. This issue can be addressed by using realtime DPM monitors. This paper presents underground mine shift average based and realtime monitored DPM values monitored in US mines. A FLIR Airtec instrument has been used for realtime measurement whereas shift average based DPM has been determined by the use of NIOSH 5040 method. A log of diesel equipment movement was kept. DPM concentrations versus time were plotted and analyzed. High DPM sources were identified and the FLIR Airtec was demonstrated to be satisfactory for realtime DPM measurements. INTRODUCTION The use of diesel equipment in mines is an attractive option due to its ability to convert a large fraction of available energy into useable work. Diesel engines are rugged, dependable and fuel efficient. It is very common for diesel engines in heavy duty trucks to have a life of 1,600,000 km [Anon, 1999]. Generally in underground mines compared to electric powered equipment, diesel equipment provides more maneuverability. It can be assumed that the underground mining industry will maintain its reliance on diesel powered equipment keeping in mind the recent developments in other energy alternatives [Anon, 2001a]. A harmful aspect to the use of diesel as a fuel is its resultant emission as an adverse environmental exposure agent. Generally diesel particles are approximately one order of magnitude smaller than respirable dust aerosols in underground mines (typically less than one micron in size) [Kittelson, 1998]. Force of gravity has less effect on DPM due to its small particle size. The phenomenon of less gravitational attraction increases the settling and residence time of DPM in the mine atmosphere. High residence time of DPM as compared to other mechanically generated particles increases the chances of diesel particles deposition in the human respiratory tract. The small sized diesel aerosols penetrate deeply into regions of the human lung [Morawska. et al. 2005], which increase the health risks associated with long term exposure to diesel aerosols. Published studies documented the adverse health effects of DPM exposure [Walsh M.P., 1999]. Continuous and long term DPM exposure can result in respiratory disease, lung cancer, reduced lung capacity, and heart disease. NIOSH has declared that the reductions in DPM exposure would reduce cancer risks. In underground mines DPM determination is a challenging task and it is becoming a matter of serious concern due to the harmful health effects associated with the exposure of DPM. The current study involves the determination of realtime and shift averaged based DPM in underground mines of United States of America (USA). Realtime DPM was measured using FLIR Airtec monitors and shift averaged based measurement was performed by the MSHA approved NIOSH 5040 method. FLIR Airtec uses laser scattering approach to measures the Elemental Carbon (EC) component of the DPM. The results from the FLIR Airtec were compared with the results of NIOSH 5040 method and its performance was found satisfactory."

Jan 1, 2015

By V. Iordachita

In the beginning of the third millennium, the world mining industry has to cope with many challenges; the continuous need for mineral resource deposits and the mostly unsolved economic efforts should be accompanied with ecologic measures mankind has to take in order to avoid self-destruction. The present paper analyses the possibilities of using underground mining spaces in Romania for storing dangerous waste and suggests viable solutions. The characteristics of dangerous wastes and their disposal in suitable underground spaces are analyzed. Also, some methods for deactivating dangerous solid wastes as well as the importance of monitoring underground spaces in order to eliminate environmental impact risks are presented.

Jan 1, 2008

By H. Majima

In spite of the importance of the presence of pyrite in the flotation of sulphide ores, not many studies have been made from the electrochemical point of view. It is generally recognized that the oxidation of sulphide minerals is one of the most Important factors among those which affect the floatability of sulphide minerals. The concept that the presence of oxygen is essential to the flotation of sulphide minerals is supported by numerous experimental results (1). The presence of oxygen in sulphide minerals- aqueous solution systems would affect the electrochemical behaviour of sulphide minerals and subsequently lead to more complicated reactions on the surface of sulphides. Actually some of the phenomena observed in sulphide flotation are deemed to be more appropriately explained from the electrochemical point of view. The author and co-workers have studied extensively the electrode reactions of pyrite and its significance in sulphide flotation. The results have been partly published elsewhere (2-7). In this paper, the author discusses the electrochemical nature of pyrite, and the three different phenomena observed in pyrite flotation: (1) Xanthate¬dixanthogen system on pyrite, (2) Flotation of complex sulphide ores containing pyrite and (3) Depressive mechanisms of pyrite with cyanide. The phenomenon which has been known as an iron contamination effect due to steel grinding media on sulphide flotation is also explained from the electrochemical aspect. However, this problem is not directly concerned with pyrite, and it will be discussed elsewhere (8).

Jan 1, 1971

By William J. Bronkala

One of the oldest tools used in mineral concentrating is the magnetic separator. Virtually every mineral handling system has need for some type of magnetic equipment in two types of basic usage. 1. Equipment protection through tramp iron removal. 2. Mineral concentration based on magnetic properties of the minerals contained in the ore.

Jan 1, 1969

By L. G. Austin

Introduction My first contact with industrial milling was during the time I worked in the electricity generating industry in the United Kingdom. In visits to power stations to investigate either deposits in the boiler furnaces or polluting deposits settling around the stacks. I had to check the performance of the vertical coal pulverizers, since poor pulverization aggravated both problems. Naturally, then, when I came to the USA in 1957 to take a PhD in fuel technology at Penn State, I was put to work to review the science of coal pulverization. After this reviewing, I was completely confused. On one hand, there was a well-developed understanding of stress-strain equations, and a rap- idly developing knowledge of how stressed, brittle solids fractured, based on the Griffith crack theory. On the other hand, reading in the grinding literature gave me: • Kick's Law, which was clearly not correct in the light of modern fracture theory; • Rittinger's Law, which was also clearly not correct; • Bond's Third Law of Comminution, which was claimed to have something to do with the Griffith crack theory, but where the connection between the two was made by intuitive pseudo- scientific reasoning I could not accept; • the choice of mill motor power for the most common type of coal mill, the Raymond pulverizer, was calculated from the fan power required to move air through the mill. Although I could accept the empirical connection between the two, it made no sense from the point of view of fracture energy. Even today, most books or review chapters on size reduction start from these laws. incorrect statements abound in the literature, such as “the Hardgrove Index is based on Rittinger's Law," which it is not, "The Bond theory states that work input is proportional to new crack tip length produced in particle breakage," which is not true, etc. My own test work showed that these "laws" did not fit the data for grinding of coal. At about this time, Epstein (1 948) and Broadbent and Callcott (1 956), following the original work by R.L. Brown (1941) at the British Coal Utilization Research Association, proposed describing breakage as a series of fracture stages. I took their concepts and developed the basic differential equation for a batch grinding process continuous in time, analogous to a batch chemical reactor. Robin Gardner then joined the project and did his PhD on treating batch grinding in the same way as a batch chemical reactor. He found that the basic equation had already been partially derived by Sedlatschek and Bass (1 953) in Germany. We confirmed experimentally the validity of the equations for describing batch grinding (1 962) and formulated the equation describing steady-state continuous grinding in a fully-mixed mill. At about the time this work was published, Gaudin and Meloy (1962) and Filippov (1961) independently published essentially the same equations, but without experimental proof of the validity of the concepts. I will give a brief overview of what these beginnings had led to in the design of mills for size and power, and show some of the results of this more detailed understanding of grinding processes. Concepts of Fracture Mills such as tumbling ball, rod, pebble and autogenous mills and vertical mills such as the Raymond, and E-type apply compressive stress to lumps or particles relatively slowly. Compressive stress applied to a particle of an elastic brittle solid imparts overall strain energy to the solid and produces local regions of tensile stress, (Fig. 1) (Berenbaum and Brodie, 1959). Irwin (1949) showed from solution of the stress-strain solutions that a small hole in a region of tensile stress reduces stress concentration at the hole, that is, the tensile stress at the tip of a crack or flaw in a solid is much higher than the general tensile stress in the region. The longer the crack, the higher the stress concentration. Griffith (1920) hypothesized that when the regional tensile stress is large enough, then the chemical bonds at a preexisting crack tip are stretched to breaking point, as illustrated in Fig. 2. When the bonds break, the crack becomes longer, the tensile stress concentration increases, the situation is unstable and a crack opens up (propagates) a surface of tensile stress, creating its own tensile stress at the leading edge. Stored strain energy is converted to the kinetic energy of the moving stress field, which is analogous to sound propagation through the solid, so the crack tip accelerates to velocities approaching those of sound. The moving crack will pass through regions that were previously under regional compressive stress. The equations for "ideal" and "Griffith" strengths are where a is the intermolecular distance, y is Young's modulus, g is the energy

Jan 1, 1998

By P. Pal Roy, Ajit Raj Ostwal, M. M. Singh

Field investigations have revealed that sawdust can be used as an efficient additive to ANFO for carrying out production blasts in limestone mines. Sawdust can be used at a reasonably reduced cost without sacrificing fragmentation, muck profile and wall control. Such additives lower the detonation pressure of ANFO by acting as low-grade fuel that reacts or burns more slowly in the presence of ammonium nitrate than does fuel oil. On detonation, it eventually forms near-ideal oxygen balance that helps in liberating maximum energy to break the surrounding rock. It also forms a low-density stable mixture that helps in reducing loading density (kg/m) of explosive in the blasthole. Experiments performed at the Hirmi Limestone mine, M/s L&T, and at the Lambasta Limestone mine, M/s Jaypee Rewa Cements, showed the novel acceptance of the technique in a highly competitive market where cost reduction has been a major area of thrust.

Jan 1, 2003

By M. C. Fuerstenau, J. J. Fitzgerald

Aluminum silicate hydrosol synthesis and characterization are discussed. Plausible polymeric aluminosilicate species are presented together with their effect on electrokinetics of selected minerals and flotation response of various ores. The addition of aluminosilicate hydrosol to porphyry and oxide copper ores and to a tungsten ore resulted in enhanced flotation recoveries ranging from about 1.5 to 5 percent. A significant portion of the nation's mineral resources are presently lost in the form of particles with very fine grain size. In the case of copper, for example, approximately 225 million tons of ore are concentrated by flotation per year in the United States. Total losses from porphyry ores are generally 15 to 20 percent with half of these losses being finely-divided copper sulfide minerals which do not respond to flotation. The additional 5 to 10 percent loss is the result of copper oxide minerals which are not floated. The losses of copper sulfide minerals are thought to be due in part to the lack of appropriate dispersion of the finely-divided solids less than 20 microns in size. To effect dispersion in flotation systems, sodium silicate is commonly added. Enhanced dispersion effectiveness is achieved when polyvalent metal salts are combined with sodium silicate. Since originally described by Patek (1), numerous workers have explored the utility of metal silicates. Makrousov (2), Belash et al. (3), and Eigeles (1950) (4) showed the applicability of these reagents to calcite/apatite and fluorite/calcite ores. Mercade (5, 6) reported depression of calcite in the presence of 3.33/1 mole ratio Al/Si hydrosols prepared from Type N sodium silicate (Si02/Na20 ratio 3.22/1) and 1% A12(SO4) 3•18H20 solutions. He importantly observed that the colloidal precipitates did not play a significant role in dispersion and depression but that the soluble species were responsible for this action. Patented work by this author described metal silicates used to depress calcite in scheelite flotation using 1% metal salt (FeSO4•7H2O, CoSO4•7H2O, etc.) and 5% Type N sodium silicate solutions to produce hydrosols with Si/Fe or Si/Co ratios of 8.79/1. Aluminum (III) ion systems were less effective as depressants than the iron and cobalt systems. Yang (8, 9) has studied metal silicate sols for use in the flotation of lithium and ultra-fine hematite ores. Using 10/1 Si/Fe mole ratio hydrosols prepared from 2% ferric nitrate, Fe(NO3)3.9H20, and 5% Type N sodium silicate solutions, solutions, he showed that the hydrosols either modify the slime particle surfaces or are adsorbed on the slime particles preventing anionic collector adsorption. In a subsequent patent, Yang also reported the use of these hydrosols as dispersants for beneficiation of lithium ores. Recent studies of aluminum silicate hydrosols in the flotation of chalcocite, chalcopyrite and scheelite have been reported using Si/Al dispersants prepared from 5% Type N sodium silicate and 0.1 M aluminum chloride (A1C13.6H20) solutions. Dispersant properties were shown to be dependent upon the method of synthesis, supernatant pH, and the hydrosol Si/Al mole ratio. Polymeric soluble species in these hydrosolsupernatants have been proposed as the active dispersant species. Aluminosilicate hydrosols are synthesized by the general reaction scheme presented in Figure 1. Commercial sodium silicates are available with ratios of SiO2 to Na20 of 1.60-3.25. The sample which is most frequently employed is Type N whose ratio of Si02/Na20 is 3.22/1.00. Gel filtration chromatography and NMR studies have shown that these sodium silicates contain numerous species of molecular weight from 325-2,000 gm/mole. Monomeric, oligomeric and higher molecular weight linear polymeric arrangements of these structures are found in these solutions.

Jan 1, 1989

By L. J. O’Connor

Mining activities in the small historic mining camp of La Colorada in the state of Sonora, Mexico can be traced back to the mid eighteenth century when gold was discovered and exploited by Jesuit missionaries. Following one hundred and twenty six years of activity, the mines were shut down due to the Mexican revolution. Very little activity took place until 1989 when a company, Minera Las Cuevas, spent US $350,000.00 in mapping and sampling and diamond and reverse circulation drilling over a period of three years. During 1991 HRC Development Corporation entered into a joint venture agreement with Minerales de Sotula, S.A. de C.V. that allowed an earn in of 70% interest. Exploraciones Eldorado, S.A. de C.V. and it's parent company, Eldorado Corporation Ltd. were subsequently incorporated by HRC to hold the La Colorada project. Property evaluation ensued and a thirty thousand tonne Run of Mine test heap was leached from August of 1992 until May of 1993. Full scale commercial production commenced in late November, 1993 and the first gold/silver doré bar was poured early in January of 1994. Pre-production costs were a total of approximately four million dollars U.S. During the fall of 1994 a buyout of the venture partners' interest gave Eldorado one hundred percent ownership of the property. The first two years of mining have utilized a local contract mining fleet and have placed nearly two million tonnes of ore on a run of mine heap. Low cost ripping and dozing mining methods have been employed in conjunction with drip irrigation leaching. An initial pilot plant carbon adsorption circuit was supplemented with a Merrill Crowe recovery circuit in June of 1994 and was completely replaced with the construction of a second Merrill Crowe circuit in July of 1995. Approximately fifty thousand troy ounces of gold and over one hundred thirty thousand ounces of silver will have been poured by year end 1995. Ongoing, on site exploration continues to increase mineable reserves in the known deposits. A feasibility study is ongoing concurrent with the operations and will provide the basis for future elevated production levels. Exploraciones Eldorado continues to explore outward from the current operations and several anomalous outlying zones may play part to the long term economic growth of the company in Mexico.

Jan 1, 1996

By I. Douni

In the last decade there is a growing interest from the society about the rational use of raw material resources and the minimization of the environmental impact of production processes and products when they reach the end of their life cycle and are disposed in the environment. In order to respond to this societal request industrial and scientific community have made considerable effort to optimize the environmental performance of the production processes and products and also to develop the necessary tools to quantify the environmental impact over their entire life cycle. In this framework the methodology of Life Cycle Assessment (LCA) has been developed about fifteen years ago and since then it has become a widely acceptable tool to quantify and assess the environmental impacts. The application of the LCA methodology can significantly assist the mining and mineral processing sector in the development of a strategy concerning the rational exploitation of raw material resources, the management of solid and liquid wastes and the optimization of the metal and mineral production processes. In this paper the work that is currently being done in the Laboratory of Metallurgy of the National Technical University of Athens concerning the Life Cycle Analysis of the production processes of basic metals, as copper, nickel, lead, zinc, aluminum etc is presented.

Jan 1, 2003

By Steven J. Page, Robert A. Jankowski, John A. Organiscak

Quartz dust is one of the most significant ongoing health concerns in coal mining today. Since initial verification of this health risk in coal mines by the Mine Safety and Health Administration (MSHA) during the early 1980’s, the Bureau of Mines has conducted numerous studies in underground mines to identify the sources of quartz dust and its fundamental characteristics. The most significant underground quartz dust source was found to be the continuous miner excavating rock. The percentage of quartz was also found to be higher in the smaller size fractions of the dust when significant amounts of rock was mined by the continuous miner. Furthermore, the quartz content in the continuous miner return remained fairly consistent at greater distances from the face. Another important factor speculated to affect quartz dust generation and its size characteristics is the morphology of the quartz bearing rock. The quartz content of dust between mines had notable differences with respect to the differences between kaolinite content in the dust. Low kaolinite content was associated with higher quartz content and increased size segregation of quartz into smaller dust particles, indicating that the free silica bonding matrix in the rock is most likely another factor responsible for quartz dust produced through mechanical comminution.

Jan 1, 1991

By Ehsan Alavi, Brian Hagan, Glen Frank, Michael A. DiPonio, Michael Mooney, Lisa Mori

"The data from EPB cells located inside the pressurized chamber of EPB TBMs and also the data from the pressure sensors in grout lines are quite important in controlling the EPB operation. However, there have always been questions in regards to pressure distribution along the shield body. Could the pressure distribution data be used to come up with potential locations for ground loss? Does the overcut region, the space between the shield body and the maximum cut diameter, consist of broken material or EPB muck, or does that region consist primarily of void space? During free air interventions, how does pressure distribute along the TBM body? To address these questions, one of the two EPB TBMs used in the Northgate Link Light Rail project in Seattle, WA is equipped with EPB cells in front and rear body to monitor the pressure distribution along the TBM body in addition to the standard 6 EPB cells located inside the cutterhead chamber and pressure sensors located at the grout lines. This paper discusses the results of this study and weighs on the valuable data that can be collected by using the shield pressure sensors.INTRODUCTIONThe cutterhead of the TBM is normally equipped with overcutters on the cutterhead periphery which extend into the annular space beyond the diameter of the TBM shield. Thus, the overcutters serve to disturb and excavate some of the ground in the annular space which reduces friction and resistance around the TBM body. This phenomenon is necessary to help the TBM steer and navigate around curves. Additionally, the shield of an EPB TBM is also often shaped like a cone, with the diameter decreasing from the front to the tail shield. This conical shape also helps the TBM to navigate because material that is cut by the cutterhead either gets pulled into the cutterhead or it gets pushed out of the way – around the cutterhead and into the annular space. In EPB tunneling, the conditioned material from the face that does not get pulled into the cutterhead mixing chamber flows into the shield gap and pressurizes the surrounding ground. Additionally, grout can travel from the segment annulus into the shield gap. The pressure in the shield gap mainly depends on the pressure of the material at the face and the grouting pressure behind the tail shield."

Jan 1, 2016

By M. R. Stokes, A. J. Ross

As a result of higher levels of production and greater depths the underground mining industry in the UK is encountering hotter climates in some workplaces. It is widely known that high heat and humidity in an underground workplace will result in reduced performance and may also seriously impair the health and safety of the workforce. It is therefore of paramount importance that the underground environment can be effectively predicted in order that sound decisions can be made to reduce the effect of climate on working personnel. Over the years numerous computer programs have been developed to predict the climate in underground mines. One such important program, developed by McPherson, is CLlMSlM TM which is a prediction model of heat and mass transfer along a single roadway. This paper describes the development of a computer model, called DRIVE, to predict the climate in single entry drivages. This program incorporates the theory established by McPherson for the development of CLlMSlM TM. This involves the algorithm for unsteady state heat transfer. Throughout the development of DRIVE underground measurements have been taken to correlate the program. DRIVE will predict the changes in psychrometric and thermo- dynamic conditions along the drivage depending on a number of parameters. Firstly, the type of auxiliary ventilation system employed such as forcing, exhausting, overlap. Secondly, the addition of heat and moisture due to autocompression, machinery, strata, fissure water, oxidation, broken rock, fallen rock, refrigeration equipment, lighting, personnel, service water. Thirdly, due to the velocity of the air.

Jan 1, 1997