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By Jon Y. Kaneshiro, Donald W. Scapuzzi

The primary purpose of the Prototype Installation Facility (PIF) for the Superconducting Super Collider (SSC) in this conceptual design was to test the magnets and other physics equipment. PIF was located in the northwest quadrant of the SSC 54 mile (87 km) main ring and consists of the first segment of tunnels, approximately 17,060 lineal feet (5.2 km) of 12 foot inner-diameter (ID) (3.7 m) tunnel, three 250 ± foot (60 m) deep shafts, connecting tunnels, and associated niches and alcoves. PIF would be the first portion of the main ring collider tunnel to be constructed. The geology, underground excavation conditions, underground facilities, and contractual considerations are discussed.

Jan 1, 1991

By Sheldon Shepherd

Fifty years ago, belt scales were mechanical devices based on a complex weight balancing design. Today's systems use load cells to assess material weight, belt speed sensors and microprocessor-based integrators to continuously compute the rate of material transferred along a conveyor. Belt scales have become important assets to a plant. They help maximize the use of raw materials, control inventories and aid in the manufacture of a consistent product. Choosing and installing a belt scale system may seem complicated but it can be simplified by following a few guidelines.

Jan 1, 1999

By James A. Brierley, Rong Yu Wan

Bacterial pretreatment was evaluated as a process for enhancing gold recovery from a refractory ore from Newmont Cold's Cold Quarry deposit. This ore is refractory due to sulfide locking of the gold and preg-robbing carbon. The microbe Thiobacillus ferrooxidans effectively oxidized the sulfide component of the ore, but the preg-robbing carbon continued to be active. Thiourea was examined as an alternative to cyanide for extraction of the gold from the biooxidized ore. The thiourea, coupled with CIL, was effective for gold extraction resulting in up to 89% gold recovery for the sulfidic-carbonaceous refractory ore. The thiourea gold complex appears not to be bound by the preg- robbing carbon of the ore when in the presence of recovery carbon (CIL)

Jan 1, 1990

By Robert C. Freas

The summer joint meeting of the East Tennessee and Carolinas Sections of SME was held in Morristown, TN, on July 29 and 30, 1994. The Friday portion of the meeting began with a field trip to Asarco Inc.'s Young Mine and Mill, one of four mines operated by the company in the Mascot-Jefferson City district. The Young Mill processes ore from two other mines as well as its own, first by heavy media separation and then by standard flotation processes. Zinc concentrates are shipped by truck and barge to an electrolytic refinery in Clarksville, TN. The heavy media rejects and the dolomitic limestone tailings are sold through Asarco subsidiary American Limestone Co. Saturday's technical session, organized by Program Chairman Bob Fulweiler of the Tennessee Division of Geology, provided a review and status report of the zinc industry in Tennessee. This article summarizes papers presented, including one on recent developments in underground blasting.

Jan 1, 1994

By V. K. Karra

Based on extensive investigations on the effect of design variables on process performance from 1982-85, Nordberg developed a 746 kW (1000 hp) cone crusher with the objective of boosting crushing productivity in existing plants. The MP1000 fits on the same foundation as the 2 m (7 ft) SHD Symons cone but is designed to give two times the capacity of the 2 m (7ft) The economies of scale involved give the customer substantial cost savings. In this paper, process performance of the Nordberg MP1000 relative to the 2 m (7 ft)SHD Symons cone while crushing the same ore, will be presented. Also, implications of such a crusher scale-up to associated cost savings will be addressed.

Jan 1, 1990

By Stephen Pogorski, Colin R. Phillips, Atika Khan

An optimized counting scheme for a mixture of radon daughters and thoron daughters typical of Ontario mines, developed in a previous study, was experimentally examined under mine conditions. The counting scheme requires a 10 minute sample and 5 1/2 hours counting instead of a 60 minute sample and more than 40 hours counting as required by a previous method. Taking into account the uncertainties associated with concentrations, flowrate and radioactive decay, the precision of the counting scheme was analyzed and found to be on average better than the 40 hour method.

Jan 1, 1981

By N. N. Clark, C. M. Atkinson

Pachuca tanks are used widely in the mineral industry for leaching and mixing operations. An analysis has been presented previously to predict circulation of homogenous slurry in Pachuca tanks with full height draft tubes. However, settling of solids causes deviation from the homogenous case. Circulation of settling slurry in a Pachuca tank is modeled and shown to be a function of settling velocity, solids fraction, solid and liquid density, air flew rate, and tank dimensions. The pressure balance is shown to be very sensitive to these parameters, especially at low slurry velocities. Equations for predicting the air requirements in Pachuca tanks containing settling solids are presented.

Jan 1, 1988

By R. Church

The southern Powder River Basin (PRB) of Wyoming has developed into the largest coal producing region in the United States in the relatively short time span of 22 years. Since the opening of the first non-captive mine in the Basin in October 1972, truck/shovel fleets have played a major part in this rapid growth. In 1994, more than 200 trucks and 50 shovels will be used at 14 mines to help produce more than 190 Mt (210 million st) of coal in the southern PRB. This article presents an overview of the truck/ shovel operations in the Basin. Fleet sizes are reviewed, applications discussed, operating considerations explored, factors looked at that drive high capacity and restrictions listed for future growth. Fleet size Various sizes of trucks and shovels can be found in the southern PRB. However, a clear trend of increasingly larger size units is being established as producers attempt to remain competitive and productive.

Jan 1, 1994

By D. R. McGregor, B. V. Clingan

A practical application of recent design concepts makes it possible to design a column cell to fit a specific set of conditions. The design and operating parameters of a column cell installation that replaced a conventional two-stage copper flotation cleaning circuit at Magma Copper Co., San Manuel, AZ, using these design concepts is described. A survey of other mineral processors using column cell technology was conducted. The results of this survey are also discussed.

Jan 1, 1988

By John A. Shuster, Joseph A. Sopko

Construction of two shafts, as well as associated deep concrete structures, for a major storm sewer project in Milwaukee, Wisconsin required ground water control and temporary ground support to depths ranging from 19.2m to 55.0m. Lowering of the site ground water table eras not possible because of potential consequences for existing nearby structures. Construction entailed completion of two shaft collars into bedrock. In addition to the shafts, several adjacent connected. structures were completed. Ground freezing was selected to provide temporary ground support and ground water control for all excavations. The first application of using reinforced frozen earth was successfully incorporated on the project. The procedure enabled the contractor to create openings in excess of 9.1m in height, without bracing, through highly stressed frozen earth walls. Design features and construction procedures for completion of ground freezing and related excavation are reported.

Jan 1, 1989

By Liuhuai Ding

Background of Ocean Mining Research Inspired by the 1970?s deep seabed mining activities of other nations, China started ocean mining research work within the framework of the International Law of the Sea Treaty (UNCLOS) and the subsequent establishment of the International Seabed Authority in the 1990?s. This work has been carried out mainly with the cooperation of the Changsha Research Institute of Mining And Metallurgy. We have been committed to this work to fulfill our responsibilities and obligations as a Pioneer investor under UNCLOS and also to support the much needed development of deep-sea technology in China. Exciting recent advances by Nautilus Minerals in the development of seafloor massive sulfide deposit exploitation has led us to a new perspective of ocean mining and some re-evaluation of ocean mining economics. This has provided us with an opportunity to support more efforts in ocean mining research. We will not delay the development of our ocean mining system and corresponding technology, although commercial mining in the deep-sea area may not occur for many years.

Jan 1, 2008

By F. -U. Schneider, F. Wellenkamp

Based on previous investigations of ultrafine comminution in planetary ball mills, a new centrifugal mill has been developed which permits similar high stress conditions. Because this new type of mill is equipped with an immobile chamber, devices for measuring energy, for cooling the milling vessel, as well as, in continuous operation, for material feed and discharge can be more easily attached than to planetary ball mills. Observations of particle behaviour have shown that, in the case of dry grinding, most of the material is found on the mill walls even after short grinding times. Due to the fact that energy dissipation takes place mainly in the zone near the wall, a grinding system which reduces the amount of ball filling required is at an advantage.

Jan 1, 1995

By P. Tsang, S. S. Peng

The stability of longwall chain pillars depends not only on the mechanical properties of the coal and surrounding rocks but also on geological and mining conditions. To evaluate the effects of each variable, orthogonal experimental design was employed in a significance analysis. The study concluded that the stability of longwall chain pillars is mainly controlled by the ratio of pillar stress to pillar strength, the ratio of the Young's moduli of roof to coal and floor to coal, entry width, pillar width and the internal friction angle of coal. Additionally, horizontal stress, panel width and mining height also play a significant role.

Jan 1, 1996

By D. W. Boening

Xanthate salts have demonstrated effectiveness as a flotation reagent in the recovery of heavy metals from mining wastewater. However, due to their strong ionic potentials, they are generally toxic to aquatic life. Under ambient environmental conditions, the half¬life of a xanthate is approximately four days. As a soluble salt, xanthates will complex with the metallic ions contained in water and fish. Some researchers have proposed that this complexing may extend the halflife, as well as optimizing the transfer of a given metal from solution across the gill surface. Leakage of xanthate treated wastewater into the surrounding surface waters is the most common route of exposure for aquatic plants, invertebrates and fish. Because this is an emerging mineral-recovery technology, more information is needed regarding xanthate toxicity and environmental fate before environmental impacts can be assessed with any degree of certainty.

Jan 1, 1999

By S. Eugene Sankey, Geoffrey L. Payne

Fundamental choices in flocculant selection often come down to the lower cost of solid grade products versus the convenience of liquids. The ideal product would be a low cost solid grade flocculant which requires minimal handling and no sophisticated dissolving equipment. Recent polymer developments have lead to the commercialization of a limited range of dry polymers that can be screw fed at controlled rates directly to process streams without the need for predissolving. Other developments include dry polymers that can be directly added to mix tanks without the need for sophisticated wetting systems. The latter will make dry flocculants especially attractive for smaller users. Examples of these new products and their application in industrial and municipal waste treatment will be provided.

Jan 1, 1994

By R. Markovic

The objective of this research study was the investigation of heavy metal removal from wastewaters of the "SARAKA" stream by using low-cost materials. These wastewaters flow into Krivelj River and through the network of existing rivers into regional water reservoirs. Sawdust, cardboard and fly ash were used as reactive materials in laboratory studies. Sawdust was obtained from oak and fir-wood while fly ash from heating station Bor, bitter-oak and oak. Experiments were carried out using real Saraka stream wastewaters and the degree of removal for iron, copper, manganese and zinc was investigated. The content of these heavy metals in Saraka stream wastewaters was under the limit of III and IV class of water (Law on Water - Official Register of the Republic of Serbia). Parameters such as flow rate of water, pH and effluent volume, contact time between water and reactive material, etc, were monitored during the experiments. All used materials give satisfactory results for iron and other heavy metals removal; the highest degree of removal was obtained by using fly ash.

Jan 1, 2006

By D. F. Martin

Sustainability is typically understood as having three interrelated dimensions-environmental, economic, and social. However, far less attention has been paid to social sustainability than to the other two forms. The paper argues that one of the difficulties in giving substance to the concept of social sustainability is that it is inherently value-dependent and has major conceptual, definitional and therefore measurement issues. This is particularly the case in complex crosscultural environments such as those found in Australian mine hinterlands with significant Aboriginal populations. Nonetheless, a concept of social sustainability can provide an important counter to the usual focus on environmental and economic sustainability, and can productively guide the minerals industry in its engagement with the Aboriginal people of mine hinterlands. The paper outlines a set of principles for socially sustainable communities, and proposes means by which these principles can be implemented. It further suggests that these principles may have broader applicability than just in the case of Aboriginal people.

Jan 1, 2005

By Fred A. Breu, Jerome C. Neyer, James F. Peters, John W. Critchfield

This paper describes experiences with methane and hydrogen sulfide gas encountered during design and construction of a sewer tunnel in rock, in Rochester, N.Y. Design explorations are summarized, including geologic setting, measurements of gasses in test borings, laboratory analyses of gas samples, and measurements of gas pressure and flow rates from a sealed borehole. Contract specifications regarding gas are outlined. Results of the Contractor's additional explorations and testing are presented, along with a description of selected equipment and provisions for ventilation and degassification.

Jan 1, 1985

By Don U. Deere

The tunnel boring machine (TBM) can be a magnificent tunneling device under optimal rock conditions. Such ideal conditions would include good Rock Material Characteristics (compact, uniform; low to medium strength, hardness, and abrasiveness); good Rock Mass Characteristics (few joints and shears; unweathered); and good Geologic Environmental Characteristics (above groundwater level and moderate in-situ stress). Such idealized rock conditions would eliminate support problems, fallout at face and grippers, frequent cutter changes, and water problems. Daily advance rates of 50 m would be commonplace. Unfortunately, nature seldom provides the ideal geologic characteristics. The challenge to the geologist, machine manufacturer, and contractor is to provide equipment and procedures to best handle the adverse geologic features, once identified.

Jan 1, 1981

By Thomas E. McNider

On July 20, 1990, a Spontaneous Combustion Control Plan was approved by MSHA for Jim Walter Resources, Inc. No. 5 Mine. The mine operated under the plan for twenty-nine shifts before MSHA revoked the plan. A total of fifty-five seals were constructed during the process of implementing the plan. The major difficulty in applying the control concept resulted from problems controlling leakage at the numerous seals. The number of seals was a direct consequence of attempting to merge the traditional bleeder system, used in all the Blue Creek Mines, with the bleederless system Jim Walter Resources proposed as a means of controlling the spontaneous combustion hazard. This paper discusses Jim Walter Resources experience with spontaneous combustion control and the new safety standard which applies to underground coal mines that demonstrate a history of spontaneous combustion and how this standard would apply to our No. 5 Mine. The new Ventilation Standards were published in the Federal Register on May 15, 1992, and scheduled to go into effect August 16, 1992.

Jan 1, 1993