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By Jeffrey J. Schwoebel, Jianliang Li, Daniel J. Brunner

A United Nations (UN) administered degasification technology transfer project, funded by the Global Environmental Fund (GEF) is underway at the Shihao Mine of the Songzao Coal Mining Ad- ministration in the province of Sichuan, Peoples Republic of China. This mine exploits multiple seams at depths ranging from 300 to 600 m below surface. In-seam boreholes and frequently spaced in-mine vertical boreholes, developed from underlying galleries constructed specifically for this purpose, currently degasify the seams in advance of mining at the Shihao Mine. Because of ventilation system constraints and the in-situ gas con- tent, longwall mining of the coals at this mine could not proceed without some form of pre-mining degasification. This paper presents a simulation based degasification plan of long, in-seam horizontal boreholes for the Shihao Mine. Simulations with a coalbed reservoir program assessed time dependent degasification characteristics of both vertical and in-seam horizontal boreholes. The simulations used input data from reservoir and desorption tests conducted at the mine site. The results produced system design nomograms to assist mine engineers in defining the appropriate borehole spacing necessary to degasify the seam in the time available for pre-mining drainage. The predicted effectiveness of the current vertical degasification scheme was compared with that for a horizontal borehole program and served as the basis for the recommended in-seam borehole configuration for the project at the Shihao Mine. The horizontal borehole degasification program requires substantially less gallery and borehole development than the present vertical degasification scheme.

Jan 1, 1997

By Jan Walaszczyk

The paper concerns the calculation of stresses and displacements in working area of room-and-pillar mining system of cooper ore mines. A three-dimensional rock mass model based on the finite element method has been developed. The complete strain-stress characteristic for pillars has been applied, but for the purpose of modeling the curve has been approximated by three segments of lines: - the first represents a behavior of pillar before a failure, -the second corresponds to a progressive pillar failure phase, - the third represents the part of the curve, where the increase of strains do not cause the stress changes, and it is called the residual strength. The criterion of model stability has been derived, which can be useful for predicting rockmass stability. The programs have been built, which allow to calculate stresses in bar elements, displacements in plate nodes, and estimate the stability of the model, which consists of plate elements and one-dimensional elements with a segment strain-stress characteristic. The programs were used to consider two different problems, which are connected with mining design and the exploitation systems.

Jan 1, 1992

By Franc Runovc

The service hoisting plant in the mining transportation is an installation serving for the vertical transport of material and persons. An adequate mathematical model is presented for simple evaluation of the project parameters where different plant designs and the ways of transport are take into consideration. The technical and economical optimization procedure is added to the basic mathematical model of the project. This approach enables on one hand the optimization of the reconstruction of the multi-purpose hoisting plants in order to suppress possible bottle necks, while on the other hand it enables the determination of such values of the parameters of the choice and of the operation that the sum of total expenses per a transport unit' becomes the lowest. The optimization procedure is designed in such a way that all numerical data of the optimum hoisting plant are printed out together with the graphical representation of dependencies of the fundamental parameters in broader optimization region.

Jan 1, 1992

By Y. C. Kim

One aspect of long-range mine planning in an open-pit mine is first to define the ultimate pit limit, i.e., the projected size and shape of the pit at the end of its life. This chapter is concerned with various techniques that are currently in use today in determining the ultimate pit limits using the computer. Prior to the early 1960's, open-pit limits analyses were entirely performed manually. This manual technique has been well explained by Soderberg and Rausch in Surface Mining (1968). Soderberg and Rausch also explain clearly the need for establishing the ultimate pit limits in long-range mine planning, i.e., location of surface facilities, dumps, etc. Consequently, the need for ultimate pit limit design will not be reiterated here. Nor will the definitions of the most commonly accepted terminologies such as break-even stripping ratio, economic cutoff grade, ultimate and working slope angles, preproduction stripping, etc. be repeated here. Briefly, the objective of the ultimate pit limit design (which is also frequently referred to as pit design in short) is to determine the projected final pit limits of an ore body and its associated projected grade and tonnage, which will maximize some prespecified economic criteria while satisfying practical operational requirements.

Jan 1, 1979

By William Highton

If the economic situation in the Western World evolves on a path similar to that of the past decade, then we Mining Engineers must accept that one of the major cost factors in the production of deep mined coal is going to be that of labour. Whilst not trying to over-simplify matters it does appear that one of the ways of maintaining acceptable coal costs is by obtaining more coal without increasing manpower. One such way could be an increase in the use of the retreat method of mining. The paper theorises and illustrates case studies to show that as the Mining Industry extends the use of Longwall retreat mining systems in coal seams where the risk of spontaneous combustion exists, then the use of bleeder entries should be questioned. In addition to the spontaneous combustion risk, bleeder entry systems where the ventilation flow is not fully controllable cannot be construed as a safe and reliable method of controlling high rates of methane emission. These two major aspects alone should be sufficient ground for Mining Engineers to re-consider the practice of using bleeder entries. An alternative "The Back Return System" appears to offer most of the advantages for controlling the environment, without the disadvantages of the other system.

Jan 1, 1980

By A. D. S. Gillies

The provision of a suitable working environment in deep level mines requires the accurate prediction of the ventilation heat load. Mathematical models for predicting strata heat load have been under development since the 1930's and 1940's. Computer models for predicting this and other mine heat sources have been developed and refined over the last 20 years. Some empirical studies have occurred and there is an increased emphasis on the importance of underground studies. Any theoretically or empirically determined predictive method must of necessity make assumptions. Underground space with its irregular configurations and rough wall surfaces cannot be described by simple mathematical expressions. Some heat loads, such as machinery, may occur intermittently while others such as the influence of water evaporation are very difficult to quantify accurately. Current popular models for predicting mine heat load have been surveyed. In testing some of these it is often found that each estimates significantly different quantitative values for the expected load in a particular underground space under study. These differences are explained by the assumptions, simplifications and omissions implicit in each of these models. It would be easier to estimate conditions at any point if heat flow into mine air passageways could be described by simple equations with associated statistically-based confidence ranges. Use of probability distributions to indicate confidence ranges allows any heat level estimate to be expressed as a range of values with limits for maximum and minimum expected values. This approach allows many of the limitations of the popular predictive models to be overcome. A heat prediction method using this approach has been developed based on Monte Carlo simulation and tested on mine data from a number of operations. Heat flow levels which can be predicted by simple equations supported by probability distributions allow the engineer flexibility in adjusting a predictive model to the underground characteristics appropriate to the mine site under study. The influence of all heat sources present in the mine opening must be included. Prediction methods must be updated as mining systems and machinery change with time. Heat sources interact with one another and the system must therefore be understood in its entirety.

Jan 1, 1987

By Wayne Charlie, Joseph P. Martin

INTRODUCTION Typically, uranium mills produce slurred tailings which are transported by pipeline to a tailings impoundment. The slurried tailings contain about 250 solids (75% liquids) by volume and, depending on the milling process, have a high or low ph. Despite decanting water from the tailings pond and losses by evaporation and seepage, Staub (1978) estimates that for lined impoundments over half of the input water is stored in the tailings. As long as the impounded tailings remain in a loose and saturated state, potential hazards exist and include potential for short and long-term seepage from the impoundments and the potential for large scale release and movement of liquified tailings should an embankment fail. The breach of an earthen dam on July 16, 1979 at Church Rock, New Mexico, and the subsequent release of 100 million gallons of water and liquified uranium tailings, underlines the potential hazard. Loose saturated tailings also have a high potential of liquefaction during earthquakes (Charlie and Wardwell, 1979; Martin, Finn and Seed, 1978; and Mittal and Morgenstern, 1976). If the tailings could be dewatered, the liner's integrity would become less critical, longterm seepage and settlements would be greatly reduced. In addition, the potential for tailings liquefaction from an embankment failure or earthquake would be greatly reduced. This paper reviews the concept, criteria, and design of various proposed interior drainage systems to dewater the tailings after deposition. ADVANTAGES OF INTERIOR DRAINAGE The primary purpose of interior drainage systems for uranium mill tailings impoundments is dewatering the tailings as rapidly and as thoroughly as possible. The expected benefits of this new technology are: • Reduction of potential seepage losses by decreasing the hydraulic head. • Reduce earthquake liquefaction potential of the tailings by inducing non-saturated conditions and/or lowering the water pressure. • Reduce the potential for large-scale release and movement of tailings should an embankment fail. • Stabilize the tailings to permit early reclamation. • Recovery and potential recycling of tailings liquid. • Inhibiting long-term seepage out of the impoundment by inducing nonsaturated conditions to provide capillary suction in the tailings.

Jan 1, 1980

The world's largest hydraulic excavator was recently introduced at Syncrude's North Mine at Fort McMurray, Alberta, in Canada. O&K's 826t (910-st) behemoth RH400, with a 42-m3 (55-cu yd) bucket, is capable of loading 72.5 t (80 st) in one pass. Syncrude's Alberta operation is the nation's largest single source of crude oil. It is also the world's largest producer of oil from oil sands. Syncrude produces 205,000 bbl/day, expects to increase production to 225,000 bbl/day by 1999 and to 320,000 bbl/day by 2005. That translates to 73.5 million bbl of Syncrude Sweet Blend (SSB) produced in 1996, 82 million bbl in 1999 and 114 million bbl in 2005. The North Mine is a new development that will replace the current East Mine, to be depleted of oil sand by the end of 1999. The North Mine will feature hydrotransport, a new and unique method of transporting oil sand from the pit to the process plant. Oil sand from the truck-and-shovel operation will be processed through a double-roll crusher and placed in a cyclofeeder where it mixes with hot water. The material is then screened and transported by pipeline to the extraction plant. Hydrotransport will replace conventional conveyor transport for moving raw product from the pit. Mine development will also use two 290-t (320-st) haul trucks to compliment the fleet of existing 218-t (240-st) trucks.

Jan 1, 1998

By Dirk van Zyl, Lysa Morishita

Mining companies are increasingly approaching the social aspect of sustainable development within the rural communities that neighbour their projects and operations. Rural community engagement requires significant effort and resources, and it can be extremely challenging for mining companies to earn and sustain social capital. The focus on rural, proximal community engagement is not to be understated and has led to significant benefits in many communities. However, opposition to mining projects is often exhibited in urban environments, where there may be potential for mining companies to gain social capital with relative ease. Cities tend to have existing frameworks for community engagement and public activation, such as annual parades and festivals, that make it easy for a mining company to provide financial support or value-in-kind. Local organizations and community groups can achieve the same amount of engagement in an urban environment with significantly less effort required from the mining company. By applying simple marketing principles to community engagement strategies, corporations can increase awareness for their business and encourage city residents to think critically about the origin of resources. Unlike many corporations, mining companies are not marketing or selling products to individual consumers. From this arises the opportunity for a company to use marketing to promote other positive initiatives and, as such, connect their brand with positive messaging thus earning social capital. This may lead to a wide variety of secondary impacts including benefits to recruitment efforts, increased political support, and positive media coverage. This paper explores these matters with special reference to Vancouver, BC, Canada and the mining companies Teck and Goldcorp.

Jan 1, 2017

By Ashis Bhattacherjee, Subrata Chatterjee, Michael T. Dewey, Christopher J. Bise

In order to continue the advancements made during the past two decades in the reduction of the severity of accidents and injuries in underground coal mining, closer attention will have to be paid to the increasing number of accidents resulting in disabling injuries and lost time. With the increased emphasis on safety training reflected in the Federal Mine Safety and Health Amendments Act of 1977 (Public Law 96-1641, and on MSHA's current focus on the application of Job Safety Analysis, it appears that the acquisition, evaluation, and application of accident and incident data will take on an even greater importance. To manage this large amount of information will require a significant commitment of time and attention on the part of mine training departments. A USBM-sponsored research project is currently being completed at Penn State which focuser on the development of a model training program for mining. The program is based on five distinct steps which represent the coupling of a needs assessment with the program implementation. The five steps are: 1) database analysis, 2) workplace observations, 3) identification of trainable problem areas, 4) a library of training resources, and 6) the implementation of the program. In each of these areas, the microcomputer has proven to be a valuable tool for collecting, analyzing, and presenting accident and incident information. This paper will detail the manner in which microcomputers have been fully integrated into the model training program. Examples of applications at existing mines will also be discussed.

Jan 1, 1992

By M. Gobla

"Since 1994 the Bureau of Reclamation has used risk analysis to evaluate dams. Risk considers both the likelihood of failure and the expected consequences should failure occur. Risk analysis relies on the detailed formulation and critical analysis of all possible potential failure modes. Potential failure modes are formulated by describing the sequence of events that must occur to result in failure, where failure is defined as the uncontrolled release of the impounded reservoir. Failure occurs in response to loadings such as water seepage through a dam (static forces), shaking from an earthquake (dynamic forces), sudden flood inflows (hydrologic forces), or accidental overfilling (operational errors). Reclamation has applied risk analysis methods to inactive and abandoned mines to evaluate tailings dams and flooded underground mines. Case histories of potential failure mode analysis as applied to mine impounded water illustrates what critical technical information is needed to determine if failure is likely, what the consequences of failure are likely to be, and what are the highest risks that should be addressed first. INTRODUCTION Impounded water, and high water content wastes, at mining and industrial processing sites are potential threats to public safety and the environment. Recent failures such as the TVA Kingston flyash impoundment failure in Tennessee in 2008 (5.4 million yd3 released), the Mt Poly Tailings Dam failure in British Columbia in 2014 (5.8 million yd3 released), and the Smarco Fundao Tailings Dam failure in Brazil in 2015 (78 million yd3 released) has renewed attention to this issue. Potential risks from impounded water at mining and industrial sites originates not only from tailing dams, but also from water in process ponds and conveyance pipelines, sediment retention dams, water retention dams, mine pit lakes, and flooded underground mine workings. Conventional water retaining dams also have a record of failure. Notable examples of failure include Vajont Dam in Italy in 1963 (2,600 lives lost), Banqiao and Shimantan Dams in China in 1975 (171,000 lives lost), and Machhu-II Dam in India (10,000 lives lost). After the 1976 Teton Dam failure in Idaho, the Bureau of Reclamation (BOR) established a Dam Safety Program. By 1984 the agency developed and began using risk analysis methods. Reclamation operates and maintains an inventory of hundreds of aging dams which were designed and constructed over a period of one hundred years. Many of these facilities were constructed using engineering design and construction methods which would not be considered good practice according to present day standards. Diligent observational monitoring, detailed site investigations, and the application of risk evaluation to the BOR dam inventory has identified many deficiencies resulting in significant demands on available funding for remediation efforts. The application of risk analysis has allowed the agency to rank sites by risk. By giving priority of remedial efforts to high risk sites, significant improvements to dam safety have been achieved. BOR has also applied risk analysis to evaluate and reclaim inactive and abandoned mining and industrial sites. The application of risk analysis methods in the mining industry is not new, the methodology was transferred to the mining industry more than 15 years ago as discussed in ICOLD Bulleting 121 (ICOLD, 2001), yet failures persist. This paper is meant to convey the lessons learned from BOR’s use of risk analyses in its work on mine sites."

Jan 1, 2017

By Yoshinori Shimada, Oleg Kotiaev, Hiroaki Sakamoto, Toshihiro Asakura, Naotoshi Yasuda, Norikazu Misaki, Masahiro Shinoda

"To ensure that trains run safely, the performance of railway civil engineering structures is checked by periodic inspections. General inspection method has merits and demerits, but none of them offers the combination of high accuracy and quick inspection. In an effort to resolve this problem, West Japan Railway Company, the Institute for Laser Technology and the Railway Technical Research Institute jointly developed a remote laser sensing system as an alternative to the impact acoustics method for detecting defective concrete elements in tunnel linings. The proposed remote laser sensing system has two lasers, one to apply an impact to the concrete surface and the other to measure the vibration of the concrete generated by the impact laser. The impact laser is a high-energy pulse laser that induces vibration in the concrete. The detection laser has a signal beam and a reference beam. The signal beam reflects on the concrete surface and goes into the dynamic hologram crystal. The reference beam diffracts in the dynamic hologram and enters the detection sensor with the signal beam. The vibration of the concrete surface can be measured to detect the movement of an interference pattern. A prototype of the remote laser sensing system was developed as shown in Figure1. A vibration and acoustic insulators are equipped to remove a noise generated from a maintenance car or electric generator in this system. The proposed laser remote sensing system and the detection algorithm were verified with the help of field test conducted in a tunnel on the Shinkansen. An impact test using hammering was applied to obtain the accurate response acceleration on the surface of the concrete before application of the proposed method. In this test, the result obtained from the proposed method has good agreement with that obtained from the impact test by hammering. Consequently, it is verified that the proposed method can be used as an alternative to the standard impact acoustics method."

Jan 1, 2016

By Kefton H. Teague

Olivine was first described and named by Warner in 1790. It is an olive green to greenish gray colored magnesium-iron silicate containing a mixture, in solid solution, of fosterite (Mg2SiO4) and fayalite (Fe2SiO4). Ratios between fosterite and fayalite in olivine are somewhat variable, but in general olivine contains at least 85% fosterite. Specific gravity is variable also, depending on the ratios of fosterite to fayalite. As a rule it is in the 3.2 - 3.4 range. All commercial olivine is obtained from the rock dunite, the most basic member of the peridotite group. Dunites, in addition to being composed primarily of olivine, generally contain assessory pyroxenes and spinels (chromite and magnetite). Dunites', when altered by hydrothermal solutions or metamorphism, often contain alteration minerals such as talc, serpentine, chlorite, vermiculite and amphiboles. In the 1930's and 40's considerable research was conducted on olivine for use as a refractory, plant food raw material, magnesium source for metal, and a source for magnesium chemicals. This research met with only limited success.

Jan 1, 1977

By A. F. Stewart

Slope design in an open pit mine includes the determination of a number of parameters, including bench height, bench face angle and berm width. By way of a case history of two highwall slopes (160m and 220m high) excavated in dipping strata in an operating coal mine, this paper illustrates the influence that bench face angle can have on the stability of an entire slope. The two highwall slopes, the lower of which experienced significant instability, were excavated in essentially the same lithologic and structural environment, with the main differences between the slopes being the angle at which the bench faces were excavated and the excavating methods that were employed. In addition to describing the instability that occurred on one of the pit walls, relevant aspects of the engineering geology, slope design and excavation procedures are described.

Jan 1, 1998

By James C. Gilliand

Leo-potpourri, was selected as the title to this paper for several reasons. First, it is a fascinating word--not looking like it sounds or sounding like it looks. It also allows for a great degree of flexibility in designing a presentation around it. Further, it has become popular to use this eco hyphen something pattern. We hear of eco-mania, eco-hysteria and the like. Lastly, in this era of intense environmental concern, two of the principle elements on which the integrity of our efforts must be equated are ecology and economics. Accordingly, the term "Eco-potpourris" allows me to roam at will through the great number of considerations that make up this environmental issue. Whereas only a few years ago the subject of environment and environmental control had low visibility with the public, today it competes as the focus of attention with the many other popular social issues of our time. The program content here at this meeting, for example, is liberally represented by papers dealing with one or more aspects of environmental concern. If one would look at the 1964 program, in contrast, I would expect that no more than possibly one or two papers covered this subject and even then that those papers dealt principally with the environmental aspect of occupational health. It is gratifying that the program at this meeting demonstrates a serious awareness to a broad spectrum of environmental concerns. It would be a mistake, of course, to believe that this clamor for a quality environment is a "flash in the pan" that will soon subside. The general public has been thoroughly aroused and even frightened into

Jan 1, 1972

By Ron Jackson

The report gives a general method for the geological evaluation of a gold deposit. Recognizable parameters associated with gold mineralization are used to develop a model of an orebody. The California Mother Lode is used as an example.

Jan 1, 1987

By Robert Martinez

A proven high grade reserve of gold mineralization located in Mexico is evaluated to determine which gold recovery process is best suited for this deposit. The processes evaluated are; Heap leaching, Vat leaching and a CIP circuit. All qualify as viable options, however each one presents a different economic picture which is impacted substantially by the financial constraints of the project. Taking this into consideration the most economic process was selected.

Jan 1, 1987

By R. J. Pruett, J. Yuan

Kaolin clays from five different commercial deposits in Georgia were studied to understand the variations of zeta potential and related fundamental properties. The results suggest that higher negative zeta potential is related to exchangeable or soluble calcium ions in the clays.

Jan 1, 1999

By Jerry Harrington, Brad Wigglesworth, David C. Beling

Commercial operations at the open pit, heap leach Crofoot Mine commenced in April, 1988. Approximately 13,600 tonnes (15,000 st) of low grade pregnant solution are treated daily using a Merrill-Crowe circuit. Acceptable gold recoveries from these low grade solutions can be obtained by optimizing solution pre-treatment prior to zinc addition.

Jan 1, 1990

By Raphael Mourad, Colin R. Phillips

Fluorescence, radioluminescence, phosphorescence and thermoluminescence in TLD 100 and 700 are discussed and compared. The energy budget in thermoluminescent material is presented in general terms. Results of measurements of radioluminescence, phosphorescence and thermoluminescence in LiF:Mg irradiated with [a] radiation, using simple facilities, are presented. The calculated energy budget in the exposed chips using [a] radiation is compared to published data using [y] irradiation.

Jan 1, 1981