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By Hill McDonald

Sand and gravel deposits may be explored by many different methods. The methods used by The Standard Slag Company are primarily two in nature. One is using an auger which is limited in depth by various soil conditions. The other is a heavy wall dry sampler and a heavy wall wet sampler. The heavy wall dry sampler takes continuous uncontaminated samples up to seven inches in diameter. The heavy wall wet sampler takes continuous uncontaminated samples up to six inches in diameter. For us, the maximum depth of the heavy wall samplers has been two hundred fifty feet of which one hundred feet was above the water table and one hundred fifty feet was below the water table.

Jan 1, 1972

By I. Iwasaki, J. N. Orlich

The effect of slurry rheology and ball coating characteristics on the abrasive wear of grinding media and the rate of grinding were studied using -10 mesh quartzite in laboratory marked ball wear tests. Pulp viscosity was found to be closely related with both the thickness and physical characteristics of the coating affecting abrasive wear. The packing density of particles at the ball surface was the primary determinant of wear while the grinding rate was more dependent on viscosity and thus the ball coating thickness. The optimum grinding rate was achieved when the coating thickness was about twice the largest particle size.

Jan 1, 1988

By Kelly F. Bailey

The issue of regulating non-asbestiform varieties of the amphiboles actinolite, tremo1ite, and anthophyllite to the same degree as asbestos has been studied in detail by the National Stone Association. The ramifications of such a regulation, and the over simplistic regulatory definition of a fiber, are enormous not only for the aggregate industry and its users, but also for the nation. Evaluation of the health, geological, mineralogical, technical, economic and legal issues do not support an "asbestos-like" regulation of non-asbestiform minerals. The adverse consequences of regulating non-asbestiform varieties of actinolite, tremolite and anthophyllite like asbestos would be magnified many times if a similar standard for generic mineral fibers were promulgated.

Jan 1, 1988

By Carleton K. Smith

Due to special job or client requirements, there will always be some variation in the philosophy of organizing and controlling construction under a project management contract. In typical cases, however, some standard procedures apply. Controls on a construction project are best described only in general terms. They should apply to the total job and can be most effective only when all pieces of the job organization fit together to support a control system for the entire project. Controls are more than a system of reports, schedules, and tabulations-they are the result of an integrated organization dedicated to getting a job done on time and within budget. One of the most important aspects of project control is the construction organization. It must include the right people, facilities, and site equipment, as well as the authority to do what's necessary to accomplish the work. This should be set up to function with as little involvement from off-site or the home office as possible. However, the jobsite construction group must work within established policies and guidelines and is subject to continuous off-site or home office monitoring. In other words, the job-site leaders need to have a clear definition of their responsibility, their authority, and the necessary people and equipment to make things happen. With that philosophy in mind, this is how Bechtel sets up a new job to be

Jan 10, 1980

Overland conveyor belts that exhibit tracking problems under loaded and unloaded conditions can be tested to' determine the root cause of the mistracking. Moveable conveyors are more prone to mistracking due to structure alignment requirements. In addition, belting quality, splice straightness and carcass condition has a dramatic effect on the performance of a belt in relation to tracking. Methods are discussed that are proven to reduce belt mistracking and improve the operational reliability of the conveyor system.

Jan 1, 1995

By Lothar Anheuser

The appearance of very large shielded softground TBM's, of 14 m (46 ft) O.D. and more, as needed for two-lane highway tunnels, calls for a thorough search of overall stability and new solutions for front support during maintenance operations in the cutting chamber. The paper deals with the development of a shield for the planned 4 th tunnel crossing under the river Elbe in Hamburg. Specific problems arise from the high water head, the shallow overburden of loose soil and the stone-bearing mixed ground. The choice of the tunneling method and the different features provided to overcome the problems are discussed.

Jan 1, 1995

By Y. Nan

A new computer simulation model for the analysis of underground coal mine production systems in the Peoples Republic of China is presented. As a case study the model was used to analyse the railway system of an existing underground coal mine. Some results of this first application are given in this paper and some conclusions of common interest for underground rail haulage systems are discussed.

Jan 1, 1986

By J. C. Barker

Alaska, with about 74% of the US continental shelf, is largely unexplored for placers in its vast shallow marine waters. Nevertheless, there are numerous occurrences of marine minerals including gold, platinum, and cassiterite. Offshore dredging has recently begun in the Nome area. State and Federal agencies are preparing additional acreage for leasing. With 76,200 km (47,300 miles) or 54% of the US coastline, Alaska is a vast, largely unexplored frontier for shallow-water marine placers. Despite the general lack of mapping and only sporadic past prospecting, many prospects are known and a major mining operation for gold has recently begun offshore of Nome. Due largely to the demonstrated success of the Nome operation, the US Minerals Management Service is preparing to conduct a lease sale of additional acreage further offshore from Nome. And future sales are being considered elsewhere by both the Federal and state leasing agencies.

Jan 1, 1990

By Dr. Richard F. Coon, James D. Mavis

Risks and abatements associated with preliminary reconnaissance, plugging and filling, and maintenance of perched mine water pool are examined. This case history showed that the initial appeal of portal plugging was replaced by concern over potential environmental hazards when details of implementation were investigated.

Jan 1, 1992

By John G. Watson, Judith C. Chow, Richard T. Egami, Daniel L. Freeman

A methodology for apportioning ambient PM-10 (particulate matter) concentrations to sources is described and applied to PM-10 concentrations in the vicinity of a large gold mining operation. With this methodology, samples representative of particulate sources such as desert overburden, diesel equipment, milling operations, road surfaces, and others are collected and analyzed to derive chemical source profiles. Ambient 6-hour PM-10 samples collected downwind from the mine are analyzed and used with the Chemical Mass Balance model to apportion ambient PM-10 among the various sources. In an example application, primary contributing source types are found to be desert overburden and diesel equipment. Relative contributions vary according to time of day, with diesel equipment frequently being the dominant contributor during nighttime periods.

Jan 1, 1991

By S. Serata

Background Results of the above study in the August 1991 issue of Mining Engineering offer valuable lessons in the solution of cutter-roof problems. The original study plan was initiated by the discussion authors to solve the problems using the "stress control method" of mining (Serata 1976,1982; Serata, Carr and Martin, 1984; Serata and Gardner, 1986; Serata, Gardner and Preston, 1986; Serata, Gardner and Shrinivasan,1986; Serata and Kikuchi, 1986; Serata, Preston and Galagoda, 1987) However, the plan and the planner were changed to the arrangement reported in the paper. The change was considered reasonable at the time due to the mine engineers' uncertainties about the stress control method. Consequently, the basic principle of the study was shifted from the original stress control method to the method described in the paper, which will be called the "yield pillar method" for the purposes of this discussion. The paper convinces the reader that the yield pillar method fails to solve the cutter-roof problems. This doesn't mean that the stress control method also fails. Actually the contrary is true, as discussed below. Limitation of the yield pillar method The paper illustrates clearly how poorly the yield pillar method performs in solving the problem. The reason for this failure is the lack of the protective stress envelope needed to stabilize the cutter roof. Unfortunately, the protective envelope cannot be formed properly without utilizing the stress control method of mining. Changing the pillar size does not make much difference in the roof stability.

Jan 1, 1992

By R. D. Deister

The Buick concentrator represents state-of-the-art technology in automated digital process control operation utilizing a centralized computer. The process control strategies implemented at Buick are no longer new to the industry, but the successful application of these developments is still rather unique in North America. Productivity improvements, determined to be a direct result of the process control developments, are the primary topics of this paper. Emphasis is placed on metallurgical benefits including both lead and zinc recoveries; lead concentrate grade; and reductions realized in reagent consumptions, operating costs, and personnel. A detailed description of the concentrator, along with a history of the process control development and a more in-depth discussion of the control strategies implemented at Buick can be found in the references. (The Buick flowsheet is depicted in Fig. 1).

Jan 1, 1987

By Scott D. Kinsala, Patrick T. Flynn, Andrew T. Rosol

During calcination of diatomaceous earth, cristobalite is formed in varying percentages. Also, during efforts to recycle products containing natural diatomaceous earth, various heat treatments are used which may or may not result in the formation of cristobalite. The ILO (International Labor Organization) Encyclopaedia of Occupational Health and Safety states that conversion begins at 450'C and in the presence of a flux, is complete at 800'C. Due to the potential adverse health effects associated with crystalline silica, a more thorough understanding of the time/ temperature relationship is needed. Tests performed under controlled conditions do not substantiate the claims made in the ILO Encyclopaedia.

Jan 1, 1991

By C. J. Webb, C. J. Paterson, A. Davis

This work focused on identifying, examining and ranking the physical and environmental hazards at inactive and abandoned mine sites in the Black Hills of South Dakota. Earlier inventory projects in the Black Hills concentrated on federal lands, while more recent efforts have examined abandoned mines on state and private lands. The more recent efforts are a result of passage of legislation by the State of South Dakota requiring a comprehensive inventory. The inventory information provides criteria for identifying those sites that require further investigation or characterization of the physical safety or environmental hazards. For most AML sites in the Black Hills, location information is all that is typically needed, because the majority of sites pose little environmental or physical hazard.

Jan 1, 1999

By Greg Blerie

The requirements placed on belt conveyors grow increasingly complicated No longer is it sufficient for the conveyors to merely move material from "Point A" to "Point B. " Now these systems must be able to produce a specified flow, guaranteeing a plant can operate as scheduled without peaks and valleys in material flow and production rate. In addition, the conveying system must provide effective control, to minimize the problems and costs associated with the escape of fugitive material these problems include unscheduled shutdowns, premature equipment failures, regulatory headaches, poor neighbor relations, and health and safety issues. The key to accomplishing these goals is the loading and discharge of the conveyor belts. Fortunately, new designs for the chutes that accomplish conveyor loading and discharge can move material efficiently, without blockages and while minimizing the amount of dust generated This innovation is the development of engineered flow chutes

Jan 1, 2004

By L. B. Paterson

Mining Engineers throughout the world have an appreciation for the importance of the role of the Blasthole Drill in one of the primary elements of the mining process. This paper highlights areas that could influence the overall cost effectiveness of that process of breaking rock and how equipment is designed and configured to meet that challenge. Factors influencing drill productivity and overall cost effectiveness are addressed, both in the Mine Environment and on the Blasthole Drill.

Jan 1, 1999

The processing capability of a semi-autogenous (SAG) mill is greatly affected by ore geology and operating variables within the mill. The SAG mill is problematic because it cannot be conveniently studied on a smaller, laboratory-scale mill. The interior of the mill, where grinding takes place, cannot be observed using instrumentation available today. Yet the motion of the rock and ball charge determines the power draft and hence capacity of the mill. Therefore, mill optimization is pursued with a charge motion simulation software. This software uses the discrete element method to describe the individual motion of numerous ball and rock particles in the mill. It is shown that by simply increasing the chord length between the lifters and increasing the face angle of the lifters the capacity of the mill can be increased. Such a configuration of lifters allows the operator to increase mill speed, hence drawing higher power while considerably minimizing direct ball strikes against shell plates and lifters. A case study of a 36 ft. diameter x 15 ft. long mill is presented. Reducing the direct ball strikes leads to lesser steel consumption both in terms of balls and lifters.

Jan 1, 2000

By M. J. Blattman

The problem of measuring the amount of rock removed during a given time interval is faced by most milling operations. Many methods have been developed with varying degrees of success, dependent upon the mining method and the availability of usable data. The Rosebud Mine has been in production for nearly two years, employing several techniques to estimate monthly production from underground production stopes. The use of three-dimensional solids generated from survey data has greatly improved the reliability and confidence of monthly production reports. The authors will summarize the methodology currently being utilized at Rosebud.

Jan 1, 1999

By Christopher Haycocks, Lawrence P. Johnson, George M. Neall, James M. Townsend

INTRODUCTION Conventional roof support methods such as mechanical and resin bolting provide adequate support for a wide variety of coal mine roof conditions. However, roof falls remain the single largest cause of death and injury in underground mines and seriously hamper production in many operations, demonstrating that these methods of roof support are not universally effective. One of the most recent and successful advances in coal mine roof control has been the introduction of the roof truss. Although past work on roof trusses (Gambrel1 and Haynes, 1970; Sheory, et al, 1973) shows little quantification of this support technique, numerous field examples have been cited where the truss effectively supported roof which could not be controlled by either mechanical or resin bolts (Kegel, 1969). The truss combines the advantages of both inclined roof bolts and post-stressing the roof. However, the full benefits of roof trusses will only be realized when design criteria to optimize support capacity are determined. The number of trusses required for a given roof condition can then be minimized, reducing installation time and making them economically more feasible. The purpose of this research is to develop roof truss design criteria based initially on laboratory studies of gravity-loaded multi-layered photoelastic mine models. Laboratory test results will then be modified where necessary following future field testing. The ensuing relationships should provide the field engineer with a reliable means of calculating optimum truss configuration, capacity, and spacing for a set of known roof conditions.

Jan 1, 1977

By Connie Travers, Ann Maest, James Kuipers, David Atkins

The science of predicting future water quality at hardrock mine sites has been practiced for at least the past 30 years. As part of the National Environmental Policy Act (NEPA), mines and other industrial facilities in the United States on federal land are required to estimate impacts to the environment, including direct impacts to water quality and indirect impacts that are later in time but still reasonably foreseeable (Kempton and Atkins, 2000; Bolen, 2002). Facilities on private land in the United States may also be subjected to State or federal processes that may or may not require prediction of potential impacts to water resources. Other countries have followed a similar approach, largely based on the requirements of NEPA. A wide array of scientific approaches has been used to predict water quality that could result from construction, proposed expansion, or other action at an industrial facility. In this study, we review the methods and models used to predict water quality at hardrock mine sites, with an emphasis on uncertainties associated with these techniques. Because water quantity and quality are interrelated, methods and models used to predict water quantity will also be discussed, but the emphasis will be on how these methods relate to water quality. This study brings together technical information on water-quality predictions at mine sites in a single paper, and attempts to present a straight-forward approach to using and evaluating the results of the methods and models used to predict water quality at mine sites. Approaches developed primarily in the United States, Canada, and Australia and applied in these countries and in other parts of the world, especially in the last 10 years, are discussed, and the format of the study is geared toward use by regulators of hardrock mines. The approach and results of this study could also be used by environmental managers at mine sites and community groups, and allows for the creation of a checklist for prediction methodology used at mine sites.

Jan 1, 2005