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By Keith S. Olsen

Any discussion of barite mining is virtually impossible without considering, almost in the same breath, the many other variables, such as beneficiation, transportation, infrastructure and location that impact the economics of a particular barite orebody. My comments will be limited to just the mining aspects of barite orebodies and these observations must be considered in proper context with all other parameters affecting exploitation of a barite property prior to final decision on economic feasibility. In many instances low-cost mining situations are more than offset by high-cost beneficiation requirements. Likewise, there are cases of relatively high-cost mining associated with no or low-cost beneficiation requirements thus permitting economic exploitation. Barite orebodies and occurrences are almost as varied as the number of occurrences. As in most mining situations, the design of a mine plan and implementation of a proper exploitation program must be approached on a case by case basis. Proper and sufficient geologic control of a barite orebody must precede the development of a mine plan. Generally speaking, barite orebodies can and, at many times, do "strange" things; pinch with depth; almost never increase in size with depth, overturn, fault-off, change grade, etc. Due to the extreme variable nature of most barite orebodies, a mine plan and its implementation must be as flexible as possible. The ability to quickly adapt to variable conditions will greatly enhance the economics within a particular barite mining environment.

Jan 1, 1980

By Charles H. Tiernon

Separation of particles on a table deck* results from differences in specific gravity, plus a number of other interrelated phenomena: size of particles; shape of particles; stratification (consolidation trickling); and hindered settling. The effective use of these factors may be controlled and aided by the following table adjustments: differential action of the drive or head motion; speed of motion; length of stroke; side tilt; end elevation; size of deck area; shape of deck; character of deck surface; riffle design; amount and distribution of wash water; feed water-to-solids ratio; feed rate; and feed uniformity. The typical concentrating table used in the US coal industry is essentially a rhombohedral-shaped deck supported by a suitable subframe. It generally slopes in the direction of the short axis, tilts upward at the refuse end of the long axis, and is differentially reciprocated in the direction of the long axis. This head motion tends to move the particles longitudinally toward the end of the table. At right angles to this movement, wash water (distributed along the high side of the table) tends to move particles down the slope parallel to the short axis of the table. Hence, the natural path of a particle on a concentrating table is from the feed box corner to the diagonally opposite corner of the deck (Fig. 1). There is a natural tendency for heavier particles to sink to the deck of the table and for lighter particles to stay nearer the surface. As a consequence, the heavier particles are carried further along the longitudinal axis since, being on or near the surface of the deck, they are more affected by the table's reciprocating action. The lighter particles, being at or near the top of the moving bed, travel slower in a longitudinal direction and thus separate from the heavy particles. Wash water and the diluting water in the feed cause lighter gravity particles to move down the short axis of the table. The feed material then fans out from the feed box, where it enters onto the table with heavy gravity particles moving in one direction and lighter particles moving in another. By properly adjusting all of the previously mentioned factors, a clear-cut separation is possible between high- and low-gravity particles, or between refuse and coal. Riffles are of great importance to tabling. They create considerably more capacity than is possible with smooth decks, and they are responsible for better separation accuracy. Particles in their downward movement along the deck's slope are delayed behind the riffles. Hindered settling, consolidation trickling, and other phenomena occur as the particles tumble over the riffles and stratification ensues. The heavier particles settle to the deck of the table and are trapped behind the riffles, thus insuring their positive movement toward the end of the table. Since stratification and separation of particles are not complete as a result of any one riffle, a series of riffles are used. The cycle of stratification and hindered settling is repeated from riffle to riffle. The result is purer products as particles fan out and progress forward and downward over the table. The smallest, heaviest particles stratify downward to the surface of the deck more quickly and are carried out by table movement toward the refuse end at a faster rate than coarse, heavy particles. Light gravity, larger pieces ride on the top layer of particles and flow down the deck's slope as a result of the cross flow of wash water at right

Jan 8, 1980

By Donald R. East

The impacts of the economic storage or disposal of mill tailing wastes are becoming more important to the mining industry as environmental regulations become more demanding. Mill tailings have long been considered the stepchild of the extraction process and have not, until recent years, been treated as a separate entity of the mining and milling process with distinct and complex physical and chemical characteristics. As a waste product, the economic value of mill tailing is usually very small whilst economic and the environmental liabilities can significant. be Disposal of tailing is commonly identified as the single most important source of environmental impact for many mining projects.

Jan 1, 1990

By K. C. Vories, C. D. Elifrits, F. F. Haston

The required reclamation of land disturbed by surface coal mining often results in the creation of some oversteepened slopes that are prone to rapid erosion and sediment production. This natural activity on such slopes is not desirable nor allowed under current regulations. Experience has shown that novel approaches must be devised to address the problem. Research conducted on field sites in Missouri has indicated that construction, during the reclamation and grading processes, of a man-made drainage system will control the erosion. The drainage system must replicate or exceed the natural system in terms of drainage density and channel frequency. Basic design considerations are summarized in this paper, and field results are shown.

Jan 1, 1987

By George M. Potter

During the late 1960s the mining industry became interested in USBM's efforts to develop the gold-silver heap leaching process. In the last 10 years, successful commercial heap leaching applications increased. The process provides a relatively low-capital means of processing treatable ores with reasonable operating costs. Present gold and silver prices compared to capital and operating costs favor the continued growth of the heap leaching method. The heap leaching process is defined as the percolation leaching of relatively coarse gold-silver ore piled on an impervious surface. To date, dilute alkaline cyanide solution is the lixiviant of choice. Other leaching reagents such as thiourea and hypo have been suggested, although they are not currently used in heap leaching practice. Ores may he run-of-mine in size or crushed as fine as about 10 mm. Gold and silver-bearing so¬lutions draining from the heaps may be processed in activated carbon columns to recover the metals, followed by stripping and metal recovery, or treated by the Merrill-Crowe zinc dust precipitation method. All solutions are generally recycled to the leaching step, and the heap leaching system is relatively easy to control from an environmental viewpoint. One advantage of the heap leaching process is its flexibility. Plants may be very simple, comprising leaching of uncrushed ore on a locally-obtained clay-lined pad and shipment of gold and silver recovered in the form of loaded carbon or zinc precipitates; such a plant would have a relatively low capital investment. More elaborate plants for larger ore bodies may be planned to include crushing, cyclic pad use, and done gold-silver recovery. General planning is similar in each case. This article outlines some key factors in designing heap leaching operations and discusses how these factors are applied to develop a working operation. Since individual design requirements and local costs vary so much, only a few general comments on costs are included.

Jan 3, 1981

By Michael McNinch, LaTasha R. Swanson, Jennica L. Bellanca, Justin Helton

As manufacturers and mine operators develop and implement proximity detection systems (PDSs), they need to be mindful of the systems’ compatibility with mineworkers’ tasks, and possible unintended consequences. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) interviewed mineworkers at mine sites that currently use or previously have used PDSs on mobile equipment, including shuttle cars, battery haulers and scoops. Mineworkers reported that mobile PDSs affect loading, tramming, section setup, maintenance and general work on the section. Mineworkers discussed the operational effects and increased burden, exposure and risk. Mineworkers also suggested that improved system task compatibility, training, logistics and PDS performance might help address these issues. Manufacturers and mine operators implementing this or similar technologies may also consider mitigating task incompatibilities up front, performing additional site-specific usability testing and restricting the use cases of the system to improve performance.

By J. W. Langhans, B. D. Blake

The U. S. Bureau of Mines has been investigating the application of thiosulfate to recover gold directly from low grade refractory carbonaceous ores for the past four years. Statistical experimental methods were used to determine the effects of various leaching parameters on both gold extraction and thiosulfate consumption. Seven variables were investigated, including thiosulfate, copper, ammonia, sulfite, and sulfate concentrations, leaching time, and leaching atmosphere. This information was used in face-centered cubic (FCC) surface response experiments to define the optimum leaching conditions for a low grade ore. Two models were generated from the data to predict gold extraction and thiosulfate consumption as a function of the leaching parameters. The models predicted a gold extraction of 67 pct and reagent consumption of 2 kg [S2032/mt ore at 0.25 M S2032-, 0.0014 M Cu2+, 0.27 M NH,OH, 0.00625 M SO;-,] and leaching for 16 h. Actual tests resulted in 62 pct gold extraction with 0.93 kg S2032- consumed/mt ore. Subsequent column leaching tests have further demonstrated the viability of applying this technology to recover gold from carbonaceous ores without first pretreating the material. Gold extractions in the column tests ranged from 69 to 78 pct with thiosulfate consumption ranging from 0.4 to 5.4 kg/mt ore. These results compare to <5 pct gold extraction using standard cyanide leaching conditions.

Jan 1, 1996

By F. C. Nicolli, J. P. Barbosa, P. S. M. Soares, A. V. Estevez

INTRODUCTION Spent household dry cell batteries are frequently disposed of with metropolitan wastestream (MSW) in landfills where they can leak due to handling or aging. Frequent rain and sun cycles, especially in tropical environments, coupled to the action of leachate, dissolve their metal constituents which will eventually reach rivers, lakes and underground water. It is well known that some of these metals are fundamental to sustain life and that is why living organisms concentrate them through their metabolism, but it has been also recognized that beyond specific limits they can definitely be deleterious to the environment. In other words, high concentration of heavy metals are proven to cause chronic or acute diseases and toxic reactions, by acting on mammals&apos; kidneys, liver and nervous system. In addition, some metals frequently used in household batteries, as mercury and cadmium, are said to be carcinogenic (Landis et al. 1995, Silva et al. 1988). Occasionally, plants to treat MSW are coupled to compost production. Household batteries present in MSW can be dragged into these plants, contaminating their products and eventually reaching vegetables making them not proper to consume by people and animals. Alternatively, batteries are also conveyed to incinerators and burned, throwing into the atmosphere volatile species. These can either act as contaminants as toxic vapor species or be delivered by winds and scavenged by rains contaminating soils and water far away from their source. In conclusion, despite the treatment applied to MSW, one can say that battery residues are potentially environmentally hazardous. The careful assessment of the environmental impact caused by residues of household batteries it is not an easy task and it can be referred as a multivariable problem. First, many different household batteries are produced by industry and the potential environmental hazard associated to their disposal depends primarily on the type of battery and manufacturer&apos;s technology. These characteristics will dictate how resistant the battery case is to handling and the

Jan 1, 1998

By Zhang Youdi

According to general guidelines, deposits suitable for surface mining can be divided into two basic categories: horizontal or flat-bedded deposits and inclined or dip-buried deposits. A series of mathematical models for surface mine long-term planning (SMLTP) has been developed and can be used for any kind of deposit. The basic theory and methodology of the models are oriented- graph simulation which combines graph and network theory with a systems simulation technique to form a new approach. From the viewpoint of surface mining and long-term plan modeling, the main differences between the two categories of deposits are analyzed, an important algorithm is put forward, and the structure of the models and some results of applications are introduced. Dynamic and comprehensive optimizations have been completed by the SMLTP model series. Combining different OR branches, the new approach has been proved to be a powerful tool to solve the strategic problems of surface mine planning.

Jan 1, 1989

By R. L. King

An expert system is a computer system that performs tasks that are considered by most people to require human expertise. Since their functioning relies heavily on large bodies of knowledge, they are often referred to as knowledge-based systems. These systems can contain the skill and knowledge of an individual human expert or the combined knowledge of a group of experts. The knowledge embodied in an expert system can consist of specific facts, HSHA regulations, heuristics or rules-of-thumb used by the expert, and databases. The purpose of this paper will be to introduce the participants in the ?Increase Competitiveness Thru Innovation? session to expert systems. This introduction will enable the participants to better appreciate the balance of the papers to be presented in this session. These papers will deal with specific mining problems and a proposed innovative solution. This paper will discuss such topics as problem-solving paradigms, rules of inference, knowledge representation, and the structure of expert systems.

Jan 1, 1989

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

The literature on four different topics is re¬viewed herein for purposes of mathematical mod¬eling of mine water inflow. The first of the topics reviewed is modeling of fissured or fractured ma¬terials; the second is general Darcy based flow models; the third is field methods for determining fracture flow properties; and the fourth is methods used presently for determining mine water inflows. The four topics are considered in the foregoing order. FRACTURE FLOW MODEL Two basic types of fracture flow models have been developed. The first type uses various tech¬niques for space averaging to obtain the equations. Systems are considered in which the porous media properties vary smoothly enough and the fracturing is sufficiently profuse and well distributed that the locally averaged properties are meaningful when viewed on the macroscopic scale. The final result is that a coefficient is used which is similar to saturated hydraulic conductivity and in many cases, simply is hydraulic conductivity. In other cases, the coefficient is apparent hydraulic conductivity be¬cause the response from flow in the fractures is more rapid than flow in the pore spaces. Faust and Mercer (1980) refers to this method as the contin¬uum approach. Some of the papers on this type of problem are by Duguid (1973), Verner et al. (1974), Owili-Eger (1975), Duguid and Abel (1974), duPrey and Weill (1974), and O&apos;Neill (1978). Duguid and Lee (1977) also considered heat flow in the fluid and the porous medium. These papers all result in various types of computer programs. Some papers on this topic that do not result in computer programs are by Snow (1968, 1969) and Streltsova (1976). Some of the foregoing articles consider con¬solidation of the porous media and the resulting effect on hydraulic conductivity. Barenblatt et al. (1960) developed an analytical solution for fracture flow and discussed the time that is involved in the drainage process and the effect that fracture flow has on the drainage time. The second type of fracture flow model con¬siders the width of the fractures as a function of the pressure in the field. Faust and Mercer (1980) refers to this method as the discontinuum approach. This approach often requires two finite element programs that consider the stress in the material and the flow in the fractures separately. The pro¬grams are then linked to arrive at the final solution. Some of the articles that consider the interrela¬tionship between pressure and the size of the frac¬ture but do not use computer solutions are Gringarten et al. (1975), Narasimhan and Palen (1979), and Witherspoon et al. (1979). Papers that use a linked computer program between stress and flow are by Ayatollahi (1978), Gale et al. (1974), and Noorishad et al. (1971). Ayatollahi&apos;s program is primarily for the petroleum industry because it does not consider the effect of gravity. Ayatollahi assumes that pressure effects are very large in com¬parison to gravity effects. This assumption would apply only to very deep aquifers. Articles that consider fracture flow on a more applied basis are by Wittke et al. (1972), who con¬siders that the flow is entirely through fissures and negligible through the pores of the rock. Gringarten and Witherspoon (1972) developed type curves that may be used for analysis of fracture flow systems; the curves are based on the assumption that it is possible to distinguish between aquifers with hor¬izontal and vertical fractures and that it is possible to analyze the system as an equivalent anisotropic homogeneous porous medium with a single fracture with much higher permeability. DARCY FLOW MODELS The Darcy flow models of greatest interest to mine water inflow prediction are those which allow

Jan 1, 1986

By Paul D. Chamberlin

There are many unit operations applicable to the processing of gold/copper ores. Deciding which are most applicable to your ore can be done using a series of tree diagrams. The diagrams show generalizations, not definitive rules. And the listing of process alternatives on the diagrams is very limited although there are dozens to choose from. Three questions help point the way to proper process selec-tion: 1. How much gold is in the ore? 2. How much copper is in the ore? 3, What is the cyanide consumption when leaching the ore?Halogens can also effectively leach gold ores and gold/cop

Jan 1, 1996

By Gerald L. Tiley

When payloads and hoisting distances are beyond the capacity of a single headrope, a multi-rope hoist will cost less than, and require less maintenance than, several hoists with one headrope per conveyance. This paper describes the basic type of multi-rope drum and friction hoists in use today, the types of ropes available, and the essentials of a satisfactory installation.

Jan 1, 1981

By A. J. Douchane, J. M. Shirley

The high grade gold and silver Ken Snyder Mine is located in north-central Nevada, in Elko County, adjacent to the town of Midas, approximately 240 miles to the east­northeast of Reno and approximately 60 miles to the northeast of the town of Winnemucca. The Midas Joint Venture (MJV), an equal partnership between Franco-Nevada Mining Corporation, Inc. and Euro­Nevada Mining Corporation, Inc. with Franco-Nevada Mining Corporation, Inc. being the joint venture manager, owns the mine. In May 1997, Kilborn Denver, now SNC-Lavalin America, completed a bankable feasibility study and proceeded with detailed design, procurement and construction management. In mid December 1998, MJV not only poured their first gold several months ahead of schedule, but were already operating at full production. In addition, the construction of this US $84 million mine, mill and related facilities were completed on budget. Operating cash costs are US $78/oz. This paper describes how this was accomplished.

Jan 1, 1999

By S. D. F. Rocha, A. L. A. SANTOS, E. M. A. BECHELENI, F. P. C. Silvas

Hydrometallurgical processes are needed to extract nickel (Ni) when it is disseminated in mineral matrix. High-pressure acid leaching (HPAL) and atmospheric acid leaching (AAL) are alternatives, and AAL has the advantage of requiring mild temperatures and pressure. Reducing-reagent tests improved the extraction of metals for the specific limiting portion of the ore. Low dosage of sodium thiosulfate presented better selectivity and safer operating conditions, allowing metal extractions of 50–62 percent at 95 °C. However, the low extraction rate obtained for Ni and the similar levels of impurities — magnesium (Mg), manganese (Mn), cobalt (Co) and iron (Fe) — extracted may represent economical and technological challenges in the downstream process.

By Thomas O’Neil

Part 2 of this article continues with a discussion of features that distinguish contemporary investment analysis in mining from earlier methods. Part 1 traced the evolution of evaluation methodology from the traditional and discounted cash flow methods to the present. Quantitative investment models of the past 20 years played an important role in mine evaluation, but a new integrated approach to mine investment decision-making is now developing because of growing economic, technical, and political uncertainties. One of those uncertainties -inflation-was discussed in Part 1. Increased Risk At a time when mineral production technology and analytical evaluation tools have never been more sophisticated, it may seem anomalous to claim that mining ventures are riskier. Whereas technical risk has, indeed, been notably reduced, business risk the chance of a major loss due to market factors-has increased. This has been caused by two factors: the rapidly rising capital requirements of new projects and increasingly unpredictable future economic conditions. These difficulties are compounded by the long lead times of large, new mining projects. Rising Capital Requirements A $100 million investment is no longer considered to be a large mining project in most cases. For a large metal mining project, the total cost of the concentrator alone can exceed $100 million. Amoco Minerals&apos; Thompson Creek molybdenum mine being developed in Idaho will cost over $350 million, for a relatively modest sized (23-kt/d or 25,000-stpd) ore operation with no extraordinary features. For a major grass roots copper operation producing blis¬ter or refined copper, the capital requirements are billions of dollars, not millions. Project costs are higher for two reasons. One, the projects themselves are larger; and two, the capital cost per unit of production is rising rapidly. Projects are larger because lower grade ores, yielding smaller margins, must be mined in greater volume-particularly in view of the high fixed costs of modern technology. When analysts contemplate any capital project, an important consideration is the minimum economic size of the facility. This is the smallest size that can be built and still be competitive on a total unit production cost basis. In the conventional copper smelting business, for example, a production rate of at least 91 kt/a (100,000 stpy) of blister copper is about the absolute minimum for reducing unit fixed costs to competitive levels. Clearly, many variables affect the minimum economic size of a mining facility, but with few exceptions that size continues to grow. Unit capital costs of new mining projects also are continuing to rise. The accompanying table shows that the capital costs in primary copper production have risen faster than the cost of living. Of particular note is the capital charge of over $1.70/kg (77411b) required for a new, fully integrated facility in 1981. Thus, the mid-1982 copper price would not even cover the cost of capital for a new copper producing complex without considering the direct operating costs for such a facility. The breath-taking costs of new mining projects are caused by factors such as increasingly complex technology, the rising social costs of creating attractive living and working conditions for employ¬ees, and the expenditures re¬quired for environmental protec¬tion. For whatever reasons, how¬ever, unit capital costs in mining continue to exhibit staggering growth rates. Future Economic Conditions Risk is not only a function of the size of the potential loss-an im¬portant measure of which is the capital intensity of mining dis¬cussed above-but also of the like¬lihood of incurring the loss. It is here that the ever increasing lead times of mining projects and the glaring limitations of economic forecasting are so important. In comparison to nearly all other in¬vestments, mining has more capi¬tal at stake for a longer period of time before commercial uncer¬tainty is resolved by distant eco¬nomic conditions that are subject to high forecasting errors. A sobering example of the pre¬ceding points occurred with the Lakeshore copper mine in south¬ern Arizona that Hecla Mining Co. undertook to finance and manage in 1969. The project was a joint venture of Hecla and the El Paso Natural Gas Co. and included two mines-one producing oxide ore and a second in the sulfide zone¬and a complex processing facility producing both electrowon cop¬per cathodes and copper precipi¬tates. The project originally was

Jan 12, 1982

By Liming Yuan, James Rowland, Lihong Zhou, RICK THOMAS, DAVOOD BAHRAMI

Continuous monitoring of carbon monoxide and other fire-related parameters by means of an atmospheric monitoring system (AMS) is used in the mining industry for early fire detection. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) have developed a direct method to calculate the fire heat release rate (HRR) when a mine fire is close to the AMS sensors, but this method is only applicable to the case where a fire occurs in AMS-monitored airways. This paper presents an improved method for determining the fire HRR using AMS sensor data at any location downstream of the fire. The method was validated using a full-scale diesel fire test conducted in the Safety Research Coal Mine at NIOSH’s Pittsburgh Mining Research Division.

By Gerald G. Griswold, Allan G. Provost

"To Sink or Not to Sink"; this play on the Bard&apos;s words sums up the considerations and problems that face the owner on every potential shaft sinking project. The growing demand for access into the earth is pressing construction into new areas and to greater depths. The following discussion will entertain some of the effects of these new and unknown aspects upon the approach to designing and sinking of deep shafts. We will also look at the current shortages of equipment, materials and skilled manpower, and their effect upon the planning and sinking of shafts. Particular emphasis will be placed upon equipment selection, and we will discuss how economics, while always a prime consideration, is now, more than ever, both an incentive and a detriment to the industry. FUTURE CONSIDERATIONS Shaft construction is assuming ever increasing importance both in mining and civil endeavors. The rapid depletion of near surface mineral reserves is requiring the mining industry to look deeper into the earth for new sources. These greater depths increase the exposure to unfavorable geological conditions; heavier ground, high water pressures, and high temperature. South African gold mines have now reached depths of 12, 000 feet, where the rock temperature is 1380 and water bursts from the fissures. In North America depths to 7, 500 feet have been sunk, but deep shafts are still generally considered to be those of

Jan 1, 1974

By Nasser Madani, SULTAN ABULKHAIR

The geological and geostatistical modeling of mineral deposits requires densely sampled drillholes that provide accurate and reliable hard data. Furthermore, quantifying orebody uncertainty through geostatistical simulation can allow mining engineers to assess long-term risk in mine planning. Nevertheless, ore deposits can sometimes lack dense drillhole information, reliable hard data with proper quality assurance/quality control (QA/QC), or sometimes both. This study is based on a coal mine located in the Republic of Kazakhstan, where an iron dataset is based on data from three newly drilled drillholes, and geological information comes from a massive collection of legacy drillhole data with no evidence of proper QA/QC. For this reason, a workflow was introduced to construct a representative training image from legacy data and stochastically model geological domains within these three drillholes using a multiple-point geostatistics technique. Once the geological model was obtained, a two-point geostatistics algorithm was applied to model the iron inside each geological domain. The direct sampling algorithm was chosen for modeling geological domains, and sequential Gaussian simulation for iron grade calculation. Both methods were extensively evaluated using different statistical tools and analyses.

Aug 1, 2022

"HISTORY Tube bundle systems have been used in the coal mining industry for gas detection since the 1960’s. At the time there were developments were underway for improved gas monitoring systems. The primary gas detection systems in use were the flame safety lamp, colorimetric stain tubes and the taking of samples for analysis by gas chromatography. The MSA D6 hand held methanometer was approved in the UK for statutory methane measurements in 1972 and became very popular due to its smallness and simplicity of use. In 1973 Sieger Limited also developed a BM1 methanometer which could be installed underground and relay methane concentrations to the surface. Similar developments were underway for carbon monoxide detection and one was developed in 1982 by the Yorkshire Regional Laboratory of the NCB commercial development was undertaken by Sieger Limited who named it the ‘SCO1’. The UNOR 1 carbon monoxide and methane analyzers were approved for underground use in the United Kingdom in the late 1960’s.5 The technique was developed by Dr Luft of Bergbau-Forschung Essen and the equipment was manufactured by Maihak in Germany. The apparatus was flame proof and provided an intrinsically safe output which allowed the result to be telemetered to the surface through colliery communication systems. Both analyzers work on the same principal and each of the gases adsorb a certain wavelengths of infrared radiation. The detector measures the residual transmitted radiation and determines the percentage of gas present in the sample. These flameproof versions had proven to be robust and reliable. The UNOR 1 had been used in the Saar region of Germany and Scotland in the UK. The development of tube bundles for hydraulic controls enabled the development of the tube bundle gas monitoring systems we know today. A bundle of tubes are taken underground through a shaft, a borehole or drift then distributed to the required monitoring points. This enabled the ongoing monitoring of the underground environment when the power was isolated at 1.25% CH4. In 1972 the United Kingdom (UK) National Coal Board (NCB) produced a hand book for tube bundle systems which was subsequently updated in 1974. This is a useful guideline into the operational aspects of tube bundles systems at coal mines6. Many of the processes identified are being followed today. The United State Bureau of Mines (USBM) prepared a circular similar to the NCB handbook on tube bundle systems.7 The circular was prepared by Litton C and it was targeted at the design criteria for tube bundle the systems. The circular also states that “pneumatic monitoring systems can be used to monitor for hazards that develop quite quickly”."

Jan 1, 2016