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By G. R. Goldak

All of Canada's older uranium mining areas have been intensively prospected and known outcrops have been repeatedly examined. The only ground in these areas which has not been explored is that which is covered by water or other overburden. The discovery of new mines in these areas will, in the author's opinion, depend on the development of new geophysical or geochemical tools capable of locating uranium deposits which are-buried beneath tens to hundred of feet of overburden. Such tools would be extremely useful in Saskatchewan's Cluff Lake and Wollaston Lake areas. Uranium has recently been discovered in significant quantities in these regions but exploration is made extremely difficult and expensive by an almost uniform overburden cover. The author's experience has been confined to Canada but apparently a subsurface uranium prospecting method could be widely exployed in the western United States and Australia as well. Radon-222 measurements have been used for more than a decade on practically a worldwide basis in an attempt to obtain a useful method for subsurface uranium prospecting. It is well known that ha-222 produced by buried uranium deposits can diffuse through an overburden cover so that it can sometimes be detected at surface. An advantage of this method of prospecting is that Rn-222 can be detected with a simple scintillation, ionization or semiconductor detector. One of the essential weaknesses of the method is that the mean diffusion path length of Rn-222 is limited by its very short (3.8 days) half life. For a deeply buried deposit, vitually all of the Rn-222 atoms will decay before reaching surface and, therefore, such deposits cannot be expected to produce a detectable radon anomaly. Thus, except in unusual cases where groundwater or ground air flow assists the movement of radon towards surface, the depth of exploration is probably limited to ten or twenty feet of overburden cover. The high solubility of Rn-222 in water is also a source of difficulty. In an area where overburden covers bedrock with water saturation of the lower overburden levels, the radon will simply dissolve in the groundwater, and soil gas readings at surface will indicate falsely low

Jan 1, 1974

By M. A. Bouchat

The Kipushi deposit, where the Prince Leopold Mine has been installed, belongs to Union Miniere du Haut-Katanga and is located in the Belgian Congo, 20 miles SW of Elisabethville, at the vicinity of the Northern Rodhesian Border. The deposit is of the hydrothermal metasomatic vein-type; mineralisation took place, through the limestone of the, lower Kundelungu. This is a special fea¬ture of the deposit, compared to the other copper deposits of the neighbourhood, both in the. Belgian Congo and in Rhodesia. Actually, the primary mineralisation of these other deposits; is directly related to the stratigraphic systems: schistous dolomitic in the Belgian Congo and Roan in Rhodesia. Both facies are older than the Kundelungu and separated from this formation by a tectonic cataclysm. The valuable elements occuring at Kipushi are principally copper; and zinc. The deposit also contains smaller quantities of lead, precious metals and other elements including germanium.

Jan 1, 1960

Due to the ongoing restructuring of the mining industry in central Europe with a continuous decline of the number of large underground mines and collieries, and a simultaneous decline of staff numbers in the remaining mines, the established mine rescue schemes are endangered to collapse. With the end of the mine rehabilitation at Wismut Uranium in 2014, the last remaining major mine rescue teams in Saxony, providing basic mine rescue services for all other mines in the region, will disappear. This will leave a large number of small mines and other underground operations without capable mine rescue support. Since none of these companies is able to set up a complete mines rescue unit on its own, new ways have to be found. Among others, a central mine rescue team for central Germany as well as the assistance by special trained professional fire fighters or mine rescue teams from abroad are discussed. Problems like location of the central rescue team, financing, communication and transport have to be solved. This paper provides an overview over the complexity of the problem as an example for other mining regions worldwide and will discuss national and cross-national strategies.

Feb 23, 2014

By R. D. Rein

The Henderson mine is a large continuous panel caving operation in central Colorado. The orebody is roughly 760 m by 910 m and will be extracted from two production levels. Each level is divided into three north - south panels 244 m to 317 m wide. The general arrangement of a production level and its associated undercut drifts is shown in Figure 1. The production drifts (3.6 m by 3.7 m) are spaced 24 m apart center to center and have undercut drifts (3.4 m by 3.8 m) 17 m directly above them. The production drifts are interconnected with drawpoint crosscuts (4 m by 4.3 m) driven on 12 m centers. Drawpoint crosscuts receive substantial brow steel and concrete support prior to undercutting. The brow steel is a 15 cm by 46 cm wide flange beam with a 2.5 cm wear plate to box in the 'cave' side of the beam. The concrete is a minimum of 0.3 m thick and the batch design results in 27 500 kPa strength. The finished drawpoint opening is 3.7 m by 3.2 m with a choke area of 3.7 m by 2.4 m. (Figure la) Undercutting and bell formation is accomplished by blasting rings of 7.6 cm holes drilled from the undercut drifts. The rings have a burden of 2.0 m and six rings develop one complete bell.

Jan 1, 1985

By Y. H. Alghamdi, A. D. S. Gillies

"INTRODUCTION Background Diesel Particulate Matter (DPM) has been a critical issue during the last decade in underground mines. This problem is threatening the health of mine workers, as well as the mine’s productivity. It has been confirmed that the diesel engine exhaust is the main source for the diesel particulate matter (DPM), and that it has the highest impact in raising carbon monoxide, carbon dioxide, oxide of nitrogen, and hydrocarbons in the underground environment. Miners who are exposed to this kind of emission are at high risk for developing lung cancer and other lung diseases. The Mine Safety and Health Administration (MSHA) has issued standard rules to regulate diesel emissions in underground mines. The final ruling confirmed in 2008 that the total carbon should not exceed 160 µg/m3. (MISHA, 2008) Monitoring DPM in underground mines has become important to ensure compliance with the MSHA regulations. There are many different types of DPM monitoring systems that are currently being used in underground mines. Two methods are typically used for DPM sampling: the personal sampling method or the direct exhaust sampling method, which takes a direct sample from the engine’s tailpipe. Many mines do not recommend using the direct exhaust sampling method since it involves complex measuring equipment and procedures, as well as it is not regulated in the United States or Canada. Thus, the personal sampling method is the preferred method in many mines when taking DPM samples. Even this method includes many variations, such as the Respirable Combustible Dust (RCD) method and the method devolved by the National Institute for Occupational Health and Safety NIOSH 5040. The NIOSH 5040 method is the preferred method overall because it gives more accurate measurements compared to the other methods. This method does not allow organic carbon sources other than those coming from diesel engine exhausts to interfere with the measurements, which otherwise would lead to overestimating the actual amount of the DPM in the mine environment. An impactor feature in the cassette, which holds the samples in the instrument, characterizes this method. Since the diesel particles are less than 0.9 micron, this impactor does not allow particles more than 0.9 microns to be collected in the cassette filter. The cassette is then analyzed in a lab and the concentrations of organic carbon (OC), elemental carbon (EC), and total carbon (TC) are determined. Lately, the National Institute for Occupational Safety and Health (NIOSH) has developed a new instrument that can use the same concept of NIOSH 5040, but with instant measurements of elemental carbon. It utilizes laser radiation with the cassette so it can give a real time measurement. The real time measurements give instant information about the underground environment that will allow the mining engineer to take immediate action and enact plans instead of waiting for results from the laboratories where NIOSH 5040 method may take several weeks to get the measurements."

Jan 1, 2016

By J. Kretschmann

Southeast Asian countries cannot maintain their economic growth rate without the development of their mining industries. To make this development as sustainable as possible requires sound fundamentals securing not only economic progress and environment protection but also improvements in occupational safety and health (OSH) for the miners. Mining in South East Asia is still very labor intense and dangerous. Tremendous achievements from world class mining operations in advanced mining countries can be used as role models to improve the status quo of the Southeast Asian countries in OSH management. Know-how transfer, therefore, is a key factor for major improvements. Effects of this transfer based on a multi-level approach will be discussed based on a case study. It describes the transfer from German to Vietnamese hard coal mining industry. Crucial requisites for excellent achievements in OSH in Southeast Asian mining countries are also mentioned.

Feb 23, 2014

By Leo R. Love

A comprehensive study of the environmental conditions of the area affected by the Colfax and Cheswick Power Stations is of extreme importance to Duquesne Light Company. The residents in the valley where the two plants are located have complained for many years about the emissions from the Colfax Plant which is of the 1920 to 1930 vintage and which has a capability of generating approxi¬mately 200 Mw. They were extremely happy to hear that the Company had plans for shutting it down, however, they were extremely unhappy to hear that we were planning to build another even larger one to take its place in the same vicinity, namely the Cheswick Plant with a capability of 570 Mw. They had visions of a plant twice the size of the Colfax Plant and belching out twice as much smoke. A few of the citizens from that area were most vehement at the public hearings that were held by the Allegheny County Air Pollution Bureau for obtaining an installation permit. With two power plants already existing in that area (Duquesne Light Company's Colfax Plant and West Penn Power's Springdale Plant), the primary concern of the Allegheny County Air Pollution Control Bureau was that the Cheswick Station might increase air pollution levels beyond what they considered to be dangerous limits. It became very evident that the Allegheny County Air Pollution Control Bureau would be extremely reluctant to grant installation and operating permits unless they were satisfied that the new plant would not increase local pollution levels and that we were taking sufficient steps to monitor the emissions from our plants and also the ambient air in the general area. We concluded that an extensive air pollution monitoring program must be conducted in the area to determine the effects of the operation of our plants. The program was conceived with our consultants, NUS Corporation of Rockville, Maryland, and was begun in June, 1968. It was designed to accomplish several things: 1. Determine the effect on the ambient air of the operation of each of

Jan 1, 1972

By N. Del Bel Belluz

Drilling underground in the Grasberg De-watering drifts has routinely hit water aquifers with high flow rates and pressures. Two types of holes are utilized; pilot-holes to probe ahead of the tunnel development to intersect aquifers ahead of the face; and de-watering holes to de-water rock formations that will drain water from the Grasberg pit and allow tunnel development to proceed safely. Recently, rates of 1050 psi static pressure have been recorded with flows from a NQ hole measured at 1350 gpm (US). The water flows can be slightly acidic, necessitating the use of stainless steel collar gear to resist corrosion. These rates were anticipated and contingencies were planned early to deal with these conditions. The collar gear is used to control water flows whereby the water is treated as an important resource. As a result, pm has established procedures to maintain safety of the drill crews, enable coring of the rock and to maintain safety of the miners who are driving the drifts.

Jan 1, 1998

By J. L. Parks

Designs, installation procedures, and performance characteristics of martensitic cast steel concaves are reviewed. Longer wear life, fewer pieces to install, and eliminating the need to scarf joints are the principal benefits of using martensitic steel to replace austenitic 12% Mn (Hadfield's) steel, the traditional concave material for large gyratory crushers. Installation procedures that reduce the risk of breakage are described. Operating practices that affect concave performance are also discussed.

Jan 1, 1992

By M. F. Dibble

The Fosfago phosphate rock concentrator is located in the state of Goias, Brazil, 300 km south of Brasilia. The ore is from an enriched carbonatite, which was discovered in 1971 during exploration for pyrochlore niobium ore. The flowsheet was developed in Brazil by personnel from Agrico Chemical Company and Consolidated South America. Engineering was provided by Codemin, a subsidiary of Consolidated, Engineering and construction management was pro- vided by both Agrico and Consolidated personnel who formed the Fosfago team. The concentrator was designed for 500,000 tpy of 37-38% P2Oj dried product. The facilities consist of open pit mining, crushing, stockpiling, and concentration. The product is pipelined seven km to a filtering, flash drying, and railroad loadout station. The plant was successfully started in May 1979.

Jan 1, 1980

By E. Ben-Awuah, H. Askari-Nasab, N. Al Habib

Open pit mines are getting deeper with time and transportation expenses are increasing because of the increasing haulage distance. In-pit crushing and conveying (IPCC) is getting popular in deeper open pit mines as a suitable alternative to truck haulage because it offers a lower operating cost due to shorter haulage distance and less truck requirement. Semi-mobile in-pit crusher, currently the most popular IPCC system, is relocated every two to five years and the short-term plan needs to be updated accordingly. Short-term planning with IPCC is an area of research that has not been explored extensively yet and hardly any model can generate short-term extraction sequence considering an IPCC in place. This research work proposes a mixed integer programming model to generate short-term production plan within a time horizon of 12 months. The objective of the model is to optimally allocate shovels to minimize cost of material handling and maximize revenue subject to meeting plant requirement, maximum allowable tonnage variation and IPCC location constraints to achieve production and NPV targets set by strategic plan. The proposed model has been implemented in a hypothetical case study for verification. The comparison of results between scenarios with and without IPCC is expected to justify the use of IPCC in large open pit mines from a short to medium term perspective. A semi-mobile IPCC system with one relocation is considered in the case study.

Feb 1, 2023

By Ed Schodowski

Wireless technology is a hot topic for anyone involved in the design, operation, maintenance or upgrading of mines or mineral processing plants because wireless technologies overcome barriers that have prevented many useful data inputs. Wireless communications can contribute to worker safety, satisfy environmental concerns, support plant security, track human and physical assets, and improve equipment maintenance. The cost structure of wireless is compelling and users can realize savings ? up to 90 percent less installed cost than wired instruments ? since wireless technology eliminates the need for expenses associated with cabling, engineering, construction and documentation. Many applications previously considered too expensive have become economically feasible with wireless. Two examples are continuous monitoring of safety showers to notify operators when one has been activated, and monitoring effluents to ensure environmental regulations are being met. In many cases, wireless transmitters can be installed where wired devices were too expensive to justify, or were not feasible due to physical or technical barriers. Examples include monitoring temperature measurements inside a rotating reactor or monitoring process variables in a tough, corrosive environment too challenging for a wired solution. Wireless also gives operating personnel mobility with the ability to communicate from remote or hard-to-reach zones. According to a recent Venture Development Corp. survey covering radio frequency (RF) of microwave industrial monitoring and control products, these features are contributing to the expected nationwide growth rate for industrial wireless applications of 19 percent annually from 2007 to 2012 (Taylor, 2008). At the same time, mineral producers have many questions about wireless systems including their applicability, reliability and security in this industry. Just what can wireless do? Is it secure and reliable? Can these instruments stand up to the rigors of the industry? Can wire-less technology provide the flexibility needed for mining applications?

Jan 1, 2009

By David M. Kjos

Large diameter autogenous and semi-autogenous grinding mills represent the primary thrust of the expanding grinding technology. In spite of initial difficulties, large autogenous and semi-autogenous mills have reached an acceptable level of technology which provides the mineral engineer with a reliable, low cost means of ore comminution. A successful milling installation begins during the design stage of the grinding mill and the plant it is to be installed in. This is particularly true in autogenous and semi-autogenous mills. Critical mill and plant design factors should be considered while the mill and installation are still only ?paper.? Various current liner designs will be discussed ranging from lifter bar/plate to integral types. Modes of operation such as "high-low" will be considered. Liner maintenance procedures ranging from laydown area in plant design, proper mill shutdown methods, to installation and bolt tightening complete the equation to yield optimum performance possible for any particular grinding application. The objective of this paper is to discuss trends in wear materials, designs and operating practices, and provide some guidelines for good practice as we move through the 1980's. We will put together concepts that relate to the designs, materials and applications so that higher performance can be obtained by the operator for his specific application. The concepts are shown as being in series because they are dependent on each other to achieve the desired performance.

Jan 1, 1985

By R. A. Hevia

Florida Power and Light is the fifth largest investor-owned electric utility in the country. It has a service territory that covers 35 counties, or 28,000 square miles, 2.5 million customers, and serves 5.6 million people. The total installed capacity is 13,470 MW, generated by four nuclear units, 36 oil and/or gas fired units, and 48 gas turbine units. Traditionally, FPL has been an oil-based utility. In 1979, this dependency on oil became obvious when 42 million barrels of oil were burned during the year. At that time, it was also projected that, based on the current estimates of customer growth and available generation capacity through 1990, FPL's residual fuel oil consumption would increase from the 1979 level of 42 million barrels (6.7 million m3) per year to approximately 55 million barrels (8.7 million m3) per year by the mid-1990's. Concern over this was further aggravated by the fact that it was difficult to estimate both the price and quantity of fuel oil that would be available over the next decade since changes in the world market, decisions by oil producers and refiners, and international political developments would all affect the availability of oil. Also, at that time, the price of residual fuel oil had increased drastically, and there was no reason to think that these prices would soon stabilize. Thus, oil back-out became a primary objective of FPL and since then, FPL has been actively investigating ways to decrease fuel oil consumption.

Jan 1, 1985

By Barbara H. Carroll

In order to rapidly evaluate an area for its mineral potential, a reconnaissance exploration program generally includes the following: 1. Outlining an area of interest 2. Identifying known mineral deposits 3. Bibliographic search of the literature 4. Evaluation of geochemical and geophysical surveys 5. Compilation and review of geologic maps The information now available from various government agencies regarding the mineral deposits, geology, and geochemistry may be integrated and used as a tool to rapidly evaluate an area before the field season. The databases most commonly used in the United States are the USBM MAS/HILS system and the USGS MRDS system for their information on mineral deposits; GEOREF and GEOARCHIVE for bibliographic information; and NURE data for the geochemistry and geophysics. In conjunction with the project geologist, this information may be used to plot known deposits and their geochemical signature as well as any other areas of like signature for further examination.

Jan 1, 1985

By S. Bahrampour

One of the basic requirements for designing an optimized rock support for an underground opening is having reasonably enough geological information. It is often financially impractical to obtain detailed geological information about the rock surrounding the excavations. The geological and geotechnical information which are obtained during the construction phase are also usually inadequate and need periodic operation stoppage. Penn State University- J.H. Fletcher & Co. joint venture is to improve the existing instrumented roofbolter so that the 3D geological and geotechnical map of the rock mass surrounding the underground working can be generated real-time as the data is being collected. This information will also be used to design appropriate support for different sections of mines. In this paper, recent results in improving the performance of the measurement while drilling system will be discussed. Moreover, updates related to borehole probing methods for estimating the properties of the rock masses will be presented.

Feb 23, 2014

By Atmesh K. Sinha

The demand for thermal coal both nationally and internationally is projected to increase rapidly. The marketability of high ETU thermal coal produced in the USA is, however, limited by its high sulfur content. Fortunately, over 70 percent of the sulfur exists in pyritic form. The research conducted at Southern Illinois University indicates that over 90 percent of the pyrite can be removed by simple devices such as concentrating tables, cyclones, or froth flotation cells and the desulfurized coal can be blended with low sulfur western coal to produce EPA compliance coal. Thus, both the low BTU western coal and the high sulfur midwestern coal can be rendered competitive in the utility markets, here and abroad due to improved utilization.

Jan 1, 1983

By E. Farrokh

CSM and NTNU models are among the most commonly used models in TBM performance evaluation. Due to increasing application of TBM in different tunneling conditions, modification became necessary for these models. Sensitivity analyses on these two models indicate that both models are very sensitive to machine characteristics. Analyses performed on CSM database for cutter load and penetration rate prediction indicate while the r-square of the CSM model is reasonably high for the predicted cutterload, the r-square value for the penetration is low. In order to increase prediction capability of CSM model for penetration rate the model was reevaluated using non-dimensional analysis and the original database of Colorado school of mines. NTNU model is evaluated using Monte Carlo simulation and regression analysis. The results of analyses indicate that the majority of the variation of the penetration in NTNU model can be explained by only three parameters. This might indicate that the effects of other factors are overshadowed and it is worthy to reevaluate NTNU model using original database and more updated statistical methods to avoid overlapping of different parameters correlations.

Feb 23, 2014

By AMIT SHARMA, BIBHUTI BHUSAN MANDAL

Operators of mining vehicles are exposed to high levels of whole-body vibration (WBV) and are therefore at risk of developing vibration-related health disorders. For implementing an effective control strategy, it is imperative to locate the source(s) of vibration, and the specific changes that might occur to the vibration signals during its transmission through the seats to the recipient human body. With this objective, Seat Effective Amplitude Transmissibility (SEAT) values of seat modules used in dumpers (n = 10) and other heavy earth-moving machines (n = 11) were evaluated in an iron ore mine. Vibration was measured simultaneously on the seat and on the cabin floor beneath the seat using tri-axial and uni-axial accelerometers. The study aims at determining the quality of seat modules of the transport and non-transport vehicles from the perspective of their natural resonance frequencies and capability of any such seat in reducing harmful vibration. The highest acceleration values were observed in the z-axis for all the dumpers. SEATrms values ranged from 78 to 133% and SEATvdv values ranged from 72 to 130% for the dumpers. For other HEMMs, SEATrms values ranged from 55 to 125% and SEATvdv values ranged from 56 to 123%. Mechanical vibration contains multiple frequency components. To understand the changes taking place to the different signals at these frequencies, 1/3 octave band analysis was carried out for the signals recorded both on the seat and the floor. There was significant attenuation (38 to 57%) at 4 Hz for three Dumper seats, whereas they resonated in the range of 1.6–2.5 Hz. The transmissibility(%) in the resonating frequencies ranged from 108 to 156%. Resonance frequencies for the remaining seven dumpers ranged from 3 to 8 Hz. The spine has been reported to resonate at 4 Hz, whereas resonance at 1.6 Hz has little significance to human beings in regard to WBV of a seated person. Hence, the characteristic resonant frequency of 4 Hz of seats as observed in the present study has the potential of causing adverse impacts on spinal health. Evaluation of SEAT factors and resonance characteristics of seats are therefore recommended to be examined while selecting a mining vehicle for regular deployment in mines.

Mar 12, 2021

By W. B. Beerbower

Resin bolting has enjoyed wide acceptance for coal mine roof support. Beginning in 1973, the first year of significant resin bolting in coal mines, we estimate that 2.5MM resin bolts were installed. This grew to 7MM resin bolts in 1974 and 13MM in 1975. Resin bolts are currently being used in over 300 coal mines throughout the major coal producing areas of the U.S. and barring major work stoppage we expect more than 17MM will be installed in 1976. Although not a cure-all, the number of unintentional roof falls occurring in many mines has been dramatically reduced as a result of converting to this "new" method of support. 1 The improved anchorage strength of resin bolts provides better roof support. (Slide #1) This anchorage strength provides a mechanism to resist changing roof stresses along the entire length of the fully grouted resin bolt, thereby assuring stabilization of rock strata over long periods of time. The ability to resist roof displacement is borne out by readings obtained from strain gauged bolts. These findings can be summarized as follows.2

Jan 1, 1977