Search Documents

By Y. Astafyev

Autotransport is one of the most conventional kinds of transport in iron ore open-pits. It. is successfully used both independently and in combination with other kinds of transport. In the Krtvoy Rog Basin open-pits annual truck transportation accounts for more than 235 million tons of ore and waste rock. In the process of operation trucks make up various transport streams depending on - the development of autoroads in the open-pits; - the capacity and the number of loading equipment ; - the load carrying capacity and the speed characteristics of trucks

Jan 1, 1979

By J. Loredo

Asturias, in Northwestern Spain, has an extensive mining history. As a result of these historical mine activities where operations have been usually developed with little control on effluents or emissions (environmental regulation of mining activity has only been introduced recently), pollution has been severe in some areas, specially in Hg abandoned mine sites, which constitute one of the major environmental problems related to mining. In many of these sites, materials stocked in spoil heaps can be considered as hazardous wastes because of their chemistry, content on ecotoxic elements and potentiality to spread these to the environment. In the humid climatological conditions of the region, water and wind eroded spoils are dispersed through the environment by different pathways and occasionally surrounding soils and waters are intensively affected by pollution. According to the environmental risks that these unreclaimed mine sites suppose for human beings and ecosystems, remedial options must be considered.

Jan 1, 2003

By James Barker, Jacques Renault, Chris McKee

Previous XRD work by us (McKee, Renault, Barker; 199Oa, 1990b) showed that by using pressed powder briquettes and a peak deconvolution technique, quartz in perlite can be routinely determined at <0.1 wt. %. In the present report, we discuss two additional methods of standardization: 1) chemical determination of quartz in silicate standards and 2) addition of a large amount of quartz to an unknown mixture. The first method applies the concept of mass balance and is sensitive to the analysis of silica and a monitor element. The second minimizes mixing errors; its equation is non-linear and is derived from the two component case with unequal mass absorption coefficients treated by Klug and Alexander (1974).

Jan 1, 1991

By Clifford O. Hamilton

In both mature and young maintenance workforces, the workforce commonly lacks some of the skills required for their assigned work. We call this the "skills gap." This skills gap usually exists in a new operation because although you may hire qualified maintenance personnel, they more often than not have little if any experience with the specific equipment at the facility. Performance Associates International, Inc., has developed and proven a technique to address the maintenance skills gap that is usually found in a new operation.

Jan 1, 2001

By G. P. Hand

Graphite usage in the United States during 1994 was fairly strong. The hearty showing of the domestic economy, along with sound performances from the major industries that use graphite, helped make 1994 a solid year for the graphite industry. Supply Virtually all natural graphite is imported into the United States, as there is no domestic production. The primary producers are Brazil, Canada, China, Madagascar, Mexico, Mozambique, Sri Lanka and Zimbabwe. Mozambique is a new producer. It is now supplying a high-carbon, large-crystallite flake in large quantities. Sri Lanka continues to experience problems with one of its two mines, closing operations in December 1994. The synthetic graphite used domestically was produced primarily in the United States as a byproduct of electrode production. Synthetic graphite was also imported from Switzerland for specialized applications. The purified graphites/carbons, such as Desulco and ThermoPURE materials, were also produced domestically. There was a sufficient supply of all types of graphite to meet domestic demand.

Jan 1, 1995

By Mike S. Ness, Allan G. Provost

High speed drilling, mucking, and hauling equipment was used in driving approximately 2.16 km(7100 ft) of lower power tunnel in quartz diorite for the Tyee Lake Hydroelectric Project near Wrangell, Alaska. The .91 m(36 in.) guage rail mounted equipment included a Tamrock 2-boom electric/hydraulic drill jumbo, a Haggl and 8HR mucker , and 3 Hagglund 115C shuttle cars. Several other innovative techniques allowed maximum advance rates of up to 17.5 m/day(57ft/day) in the 3 m(10ft) horseshoe section. Average tunnel advance was approximately 11 m(day(35.4 ft/day). The primary difficulties preventing full utilization of the equipment potential were the operators&apos; "learning curve", the need for complete retraining of all personnel in the new methods, and minor sections of faulted ground.

Jan 1, 1983

By R. L. Grayson, T. L. Dickinson, C. G. Anderson

Sponsored by the EPA, USGS, DOE, and NSF through the Committee on Earth Resources, the National Research Council’s Committee on Material Flows Accounting of Natural Resources, Products, and Residuals, created in August 2002, studied the value that material flows accounting, which can track the flow of a material from the time it is extracted to its ultimate disposal, may provide for making better integrated economic, social, and environmental policy decisions. This could be a crucial technology for the mining industry to incorporate. This paper will recount the statement of tasks, the study process, and the science-based conclusions and recommendations reached.

Jan 1, 2004

By Gary A. Perry

Cyprus Sierrita produces copper and molybdenum from its Sierrita and Twin Buttes open pit mines south of Tucson, AZ. Both pits were started in the late 1960s and are more than 460 m (1500 ft) deep. Sierrita has used a Caterpillar 992C Remote Controlled Loader since January 1993. The loader was justified to increase safety and profits at Sierrita. It has exceeded all expectations. As of June 1993, the 992C had produced additional profits of more than $1.5 million. Safety and Geotechnical The safety of Cyprus personnel and equipment is always of prime concern. The remote controlled loader removes personnel from the active raveling area. But it requires prudent operation. The remote controlled loader discussed here is always intended to be used in a safe manner under a managed slope. Any increase in slope angle or use of any equipment under a critical slope is taken only after careful analysis of the specific

Jan 1, 1994

By Henry Brehaut

The International Network for Acid Prevention (INAP) was formed in 1998 by 17 international mining companies to promote significant improvements in the management of sulphidic mine materials and the reduction of liability associated with acid drainage through knowledge sharing and research and development of technology. Since its inception two panels have been formed to identify and move forward with research projects and eight networks have been constituted to initiate interaction and knowledge sharing within the membership in specific areas of technical interest. An INAP web site has been developed to facilitate the sharing of information and to encourage the exchange and development of new ideas.

Jan 1, 2000

By Arthur F. Moss

Smallbore tunnels in urban environments often present more technical and managerial problems than major large diameter schemes carried out for transportion, water supply and hydro-electric facilities. The 1.8 km Bath scheme was designed for construction in tunnel using the pipe jacking system. Unforeseen ground conditions meant other techniques were needed during construction. The paper describes the problems encountered and how they were overcome.

Jan 1, 1981

Reclamation of surface mines is a crucial environmental issue and a key challenge to the worldwide mining industry. One of the goals of reclamation is to ensure that the area is left in a condition permitting safe future use. Hence, the reconstruction of open pits, waste piles and tailings dams must satisfy appropriate geotechnical stability and safety conditions for the planned use. Landscaping in the final stages is highly relevant as the topography around the mining areas is sometimes dramatically modified by ore extraction. The reclamation strategies must be applied not only after ore exhaustion, but also during its extraction. This is a sound business strategy that leads to considerable environmental benefits and increased security of the mining operations.

Jan 1, 2003

By Walter Shukin, Mark T. Olsen

An enormous quantity of tailings to be ultimately stored, unfavorable topography, severe climatic conditions, and an environmentally offensive red effluent all contributed to the challenge of designing an effective and cost efficient tailings confinement program at the open-pit iron ore mine operated by Quebec Cartier Mining Co. at Mount Wright in northeastern Quebec. The mine has been operating since 1976, but a detailed disposal plan was first initiated with construction of some channels and ditches during 1980. In the coming years, a system of dams, channels, and tailings confinement dikes will be constructed to accommodate tailings produced in the next 25 years. Careful consideration has been given to environmental effects, and the works under construction have been sized and situated to be extended as required to an ultimate mine life of 87 years.

Jan 8, 1981

By A. Smithson

It is generally accepted by British mining engineers that coal will continue to be worked by the. advancing or retreating longwall system for the foreseeable future. At the coal face, the emphasis will be on better machine utilization; increased equipment reliability; modular design and more standardization; remote control and monitoring; and a continuing drive to increase productivity and safety. Improvements at the face can be sustained only if there are corresponding improvements in efficiency elsewhere in the mine. Coal handling systems, for example, must be able to accept increased tonnages without creating bottlenecks. As workings move further from the shafts, the time taken to transport men and materials must be kept within reasonable limits. Development drivages must he on schedule to be ready for the planned opening of new faces, and face ends must keep up with faster moving faces.

Jan 8, 1981

By P. C. O. Chukabarah

Many aerodynamic and thermodynamic properties (such as temperature, pressure, velocity and density) vary widely, and in random spatial and temporal manner for a given underground mine environment. Such variabilities are seldom evaluated statistically, even though the relevant theories and principles are both available and feasible. The main purpose of this paper is to introduce the methodology for applying aerostatistics to the analysis of multiple fan systems in mine aerology/ventilation. Pertinent data were obtained from a small multi-level European coal mine. Results confirmed that aerostatistical methodologies are computationally more efficient. Being grounded in solid engineering statistical theories, they can be used to analyze networked parameters in mine environmental engineering.

Jan 1, 1995

By David L. Moffatt, Leon Peters

A unique electromagnetic pulse sounding system for the detection and identification of geological and man-made anomalies which represent hazards in hard rock rapid tunneling operations is described. The main features of the system including a periodic video-type pulse interrogating signal and a probe structure that permits operational modes which either "see" or are "blind" to homogeneous-type targets are reviewed. The results of experimental pulse measurements on targets buried in the overburden and in a limestone medium are presented. Since the electrical properties of limestone are not radically different from those of a hard rock medium, conclusions based on these data should be valid for a hard rock media also.

Jan 1, 1997

By Lawrence M. Lenahan

Cleveland&apos;s Southwest Interceptor Contracts No. 3 and No. 4 are continuations of Contract No. 1 addressed at the 1987 RETC with geology, equipment, and methods that differ greatly. The two contracts consist of 791 m (4.22 miles) of 3.5 m (11.5 ft) tunnel lined to 2.9 m (9.5 ft), nine access shafts, six drop shafts, and six collection structures. The excavation drive was completed by the use of a 1970 vintage Robbins TBM hybrid for this particular job through the use of both new and old technology. All other excavations were successfully accomplished through drill and blast method in tight residential areas. Concrete lining and connections were completed nine months after holing through.

Jan 1, 1989

By Michael S. Robinson, Serge Moalli

Construction of the CSO Retention - Treatment Tunnel, Segment 1 in Dearborn, Michigan includes excavation for an overflow Structure with a minimum inside diameter of 15.24 m (finished). The excavation extends downward through overburden soil including a 15.2 m thick zone of potentially weak clay. This paper presents the subsurface data for the clay and a geotechnical analysis thereof, together with predictions of the behavior of the planned 15.54 m inside diameter open end caisson as it is sunk through this potentially weak zone. In a companion paper, the writers will compare the behavior observed with that predicted.

Jan 1, 1995

By A. Mahtab, S. Xu, P. Grasso, B. J. Fu

The large population base, complex geology of the large land mass, and notable commercial activity have accelerated the development of underground construction market in China. The projected lengths of underground openings per year in the various sectors are: hydro-tunnels, 180 km; coal mine entries, 40 km; transport-tunnels, 300+ km. An example of the mega projects (being planned by the Government) is the water supply scheme for connecting Yangtze river to Yellow river involving 131 km of water tunnels with a diameter of 8-10m. Several large projects are highlighted in the paper with reference to the schemes for generating hydro-power, mining of coal and minerals, and constructing transportation networks. The related problems of construction and geomechanics are outlined.

Jan 1, 1995

By Norbert Patzelt

The high-pressure grinding roll was introduced about 10 years ago and has established itself in many applications. Most of these machines are used in grinding circuits in the cement industry. A few operate in conventional mineral-processing plants. Polysius has sold more than 350 Polycoms worldwide. An exception is diamond-ore processing in South Africa and Australia. This type of grinding system increases diamond liberation and reduces the capital costs for the downstream processing plant. There are several reasons why high-pressure grinding rolls have not been used more extensively in the mining industry: - The mining industry adheres to conventional grinding technology and regional preference for certain comminution circuits. - Design, scale-up and flowsheet assessment procedures are viewed as being immature and reduce confidence in the potential application of the technology. - Downstream process benefits are unproven on a plant scale.

Jan 1, 1995

By Fred H. Lightner

Mergers and acquisitions (M&A) within the mining industry are becoming frequent events. Large companies and small companies alike are jumping on the bandwagon of merger mania. The results of these mergers have significant impacts on the employees of the involved companies. Comments, observations, and specific examples of the &apos;peop1e"aspect of mergers are presented in an attempt to answer the question "will it be business as usual?" My answer is a simple NO. This paper attempts to provide support for my conclusion. The reader should recognize that the comments, observations, and specific examples mentioned in this paper are subjective and reflect the experience and prejudice of the author.

Jan 1, 2001