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By Gary Buchan

During several months in 1996 and 1997, Cyprus Twentymile Coal Co. (TCC) set world production records at its Twentymile Mine in northwestern Colorado. These records were due to the company's implementation of a state-of-the-art longwall mining and conveyance system along with a -highly dedicated work force. This article is a case study of the design of long panels at the mine from conception to implementation. Obstacles that needed to be overcome included subsidence engineering, environmental regulations, conveyance, ventilation, equipment design and continuous miner (CM) development timing.

Jan 1, 1998

By Saskia Duyvesteyn

Small ion-exchange resin particles provide faster mass transport than conventional-sized beads. Unfortunately, high pressures are needed to pump solutions through columns containing small resin particles. It is preferable to disperse fine resins in the solution being treated. Screens have been used to separate the resin from the solution, but screens do not retain fines created by attrition of the resin particles. We have developed a separation process based on flotation, which relies on the surface characteristics of the resin, instead of size. The resin is conditioned with a surfactant before dispersing it in the solution to be treated; this increases the hydrophobicity of the resin sufficiently for froth flotation, without introducing surfactant directly into the solution. The surfactant adsorbed on the resin surface does not appear to impair the kinetics of metal ion removal. A flowsheet for an effluent treatment process is proposed; other applications are clearly possible.

Jan 1, 1998

By Downs M

The use of a cutting machine designed to allow simultaneous cutting and setting of roof supports has numerous advantages few development roads in coalmines. The use of such a machine with the added ability to cut a curved roof profile is of considerable interest for longwall development in thick coal.

Jan 1, 1998

The emergence of a new range of database communication standards and software has provided the impetus for the development of a new approach to exploration and mining data management. The acQuire software produced by acQuire Software Pty

Jan 1, 1998

By B. T. Field

Pyroprocessing systems range from low temperature dryers to high temperature reactors. The materials and process requirements cover a broad spectrum. It is not the intent of this paper to do a detailed examination of individual processes and equipment, since that can be found in a multitude of other sources; rather it is the intent of this paper to examine the key process variables and offer empirical guidelines to assist in a user?s overall evaluation.

Jan 1, 1998

By S Jahanshahi, D R. Swinbourne

A knowledge of the value of the activity coefficient of cobalt oxide in slag as a function of composition and temperature is necessary if effective strategies are to be devised to maximise the recovery of cobalt in nonferrous smelting processes. This work reviews previous studies and shows that comparison and evaluation of the results is hampered by variations in the choice of standard states for the species. Published results have been recalculated to a common set of standard states with a preferred value for the Gibbs free energy of formation of cobalt oxide. It has been shown that the value of the activity coefficient of cobalt oxide referred to the solid standard state in iron silicate slags is approximately two, at temperatures from 1523 to 1623¦K. It is suggested that some contradictory results are most likely due to errors in the measured partial pressure of oxygen.

Jan 1, 1998

By V. Paul Keran

Design of the Bajo de la Alumbrera project started in June 1995. Concentrate production began early in the third quarter of 1997. The project is situated in northwestern Argentina. Alumbrera is being developed by Minera Alumbrera, which is owned by MIM Holdings of Australia (50%), North Limited of Australia (25%) and Rio Algom of Canada (25%). Alumbrera is Argentina's first modern copper mine. This article outlines the key process- and plant-layout features that were incorporated in the Alumbrera concentrator design. It explains the background of flowsheet and equipment selection for the plant. A feature of the flowsheet is that it incorporates gravity-gold circuits in both the primary and the regrind circuits for recovery of gold to dore as well as in the copper concentrate product.

Jan 1, 1998

By Olga A. Gomon, Alexey N. Lozhko

The technology of heat treatment for metal frequently includes multiple fast heating and cooling of the products surface. If the product is heavy-weight or long-size, its moving from a zone of cooling to a zone of heating and return require a long time. Other important condition of ensuring qualitative surface at heat treatment is intensification of cooling phase. It is known that turbulization of a flow activates heat exchange and increases efficacy of cooling without increasing volume flow rate of water. Additional difficulty is to ensure the regularity of heating and cooling on length of a product. The technology of cyclic heat treatment of rolling products, at which mobile zone of turbulent heat exchange is formed on the surface of a product, was developed and realized. The submission of water occurs through to face spray systems. Each of the systems has six long-range atomizers, which are located circularly. Two flows of water move towards one another along a surface of a product. When they collide, the right zone of turbulent heat exchange creates heat transfer in this zone of 10-15 time more intensive than on other surface of a product. The effect of moving turbulent zone on length of a product is reached by changing the proportion of volume flow rate of water, which is created by face sprays. The speed of movement for turbulent zone along a surface of a product is chosen so, that the cooling takes place on a small depth only. Then after passing the turbulent zone over a determined site of a surface, its temperature recovers fast owing to hot internal layers. The parameters of process were determined by mathematical simulation of cooling in an installation. The equations for dynamics of movement of collision point of flows, which were received this way, are interesting supplementary products of research. The experiments show that frequency of movement of turbulent zone is an important technological parameter. It defines mechanical properties of a surface and should be chosen depending on a profile of product and metal grade. The results of comparison of mechanical properties of a surface of various rolling products, which were received by developed and conventional technologies, are described in this report. Dependence of regularity of mechanical properties on frequency of movement of turbulent zone is adduced.

Jan 1, 1998

By Yuchun Wang

In principle, supported liquid membranes could be an exceedingly elegant separation process. However they tend to fail by displacement and emulsification of the organic solution in the pores, which allows mixing of the feed and strip solutions. We have stabilized supported liquid membranes comprising moctylamine in nylon and PVDF supports by covering the pores with semi-permeable polyamide films, using an in-situ polymerization technique. Scanning electron microscopy demonstrates that the polyamide films are sensitive to production conditions and the nature of the support. The transport properties of stabilized supported liquid membranes for Cr(VI) are compared with those of unstabilized membranes.

Jan 1, 1998

By Don Thompson

The Minntac Mine drills and blasts approximately 75 million long tons of taconite per year. This requires drilling one million feet of 1 6-inch diameter holes. We are in the process of replacing our old generation rotary blasthole drills (Gardner-Denver 120's and Bucyrus-Erie 61R's) with new generation rotary blasthole drills (Bucyrus-Erie 59R's and P&H 120A's).

Jan 1, 1998

The sixth international symposium on mining with fill nearly coincides with the 25th anniversary of the Jubilee Symposium on Mine Filling. That symposium, held in August 1973 in Mount Isa, in part to commemorate the 80th anniversary of The Australasian Institute of Mining and Metallurgy, was the first in what has turned out to be a very successful series of symposia. Subsequent symposia were held in Sudbury, Canada (1978), Lulea, Sweden (1983), Montreal, Canada (1989) and Johannesburg, South Africa (1993). The series of symposia has now become an established part of the mining industry calendar, and it will be interesting to see which country is given the honour, and accepts the challenge, to organise the next symposium.One way of predicting the future, or some small part of it, is to revisit where we have already been with a view to determining the existence of any trends that may impact on the future. An historical review of filling practice and research, with special emphasis on Australian experience in particular and worldwide in general over the previous 25 years, will enable me to address the historical and predictive objectives. Controversy can always be achieved by producing a best of list; it can be guaranteed that everyone will disagree with at least one of the nominations. On this occasion, the best contributions by individuals or groups in a number of areas of mine fill technology, over the last 25 years, will be the basis for the nominal awards. The controversy can be increased by posing a number of questions that, hopefully, some of the authors will address during their presentations. I imagine the social functions will be busy enough, but the questions may just add to the cut and thrust of the debate.

Jan 1, 1998

By F. Calizaya

This study summarizes the ventilation requirements for a highly mechanized P.T.Freeport Indonesia's underground mine operation in Irian Jaya, Indonesia. The Deep Ore Zone (DOZ) is a copper-gold deposit being developed underneath the current Intermediate Ore Zone (IOZ) mine. One of company's current plans is to prepare this mine for a steady oreflow of 25,000 tpd by year 2003. This study includes the estimation of airflow requirements for various mining activities, the design of major intakes and returns, the determination of airway resistances and specifications of fan duties. It also includes the results of air pressure/quantity measurements in existing airways and the standards stated by the current Indonesian mining law.

Jan 1, 1998

The Lennard Shelf Operations owned by Western Metals Ltd evolved from the Cadjebut Zinc Lead Mine (BHP) in August 1994. Original production of 0.5 mtpa will rise to 2.0 mtpa at the end of 1998. Employees work a multiple of fly-in/fly-out (FIFO) rosters from the Kimberley region and the WA Capital. The three underground mines, treatment and services departments will employ approximately 300 people by the end of 1998. The expansion of the Lennard Shelf Operations as a remote mining location was based on a fresh look at management systems and employee rosters which were generated from many years of mining experience. This paper will endeavour to summarise these experiences and analyse some of their outcomes. Dealing with several mining methods, engineering difficulties, logistical problems and climate extremes, the Lennard Shelf Operations has managed social/employee issues with excellent results. Much time has been spent to get this correct for the Lennard ShelfÆs own set of circumstances. Employees and associated companies must expect continuing changes and improvement as Western Metals strives to continually improve its management systems and employee rosters.

Jan 1, 1998

By Tracy Brettmann

The use of rock-socketed Augered Cast-In-Place (ACIP) piles is new to the Austin and central Texas region. This case history describes the design methodology, load test results, quality control procedures and the rate of production pile installation for the first large commercial project where ACIP piles were used in Austin. The piles were 24 inches in diameter and extended through about 45 ft of alluvial materials to be socketed 6 ft into limestone. A full-scale instrumented load test was performed on a test pile that was loaded to 452 tons and held for 24 hours. Telltales were installed in the middle and the tip of the test pile. As part of the overall quality control procedures, singlehole sonic integrity logging was performed on the production piles to verify structural integrity during pile installation. During pile production, an average of 14 piles per day were installed, which is approximately seven times faster than the original design that consisted of drilled shaft foundations.

Jan 1, 1998

In-seam drilling is conducted mainly to drain coal of gas and/or water prior to development or extraction. The requirements of inseam drilling for gas drainage have mainly surpassed the technical limits of rotary drilling and are mainly being addressed by guided down hole motor drilling, albeit at a higher cost. There is an increasing application of in-seam drilling to detect geological structures or other hazards or their absence in advance of mining to reduce the risks of underground mining. Close collaboration between miners, drillers, geologists, researchers and suppliers over the last four years has seen many advances made to improve the accuracy and reliability of inseam drilling. With such developments will come closer control over the ventilation and safety of future mining under deep gassy conditions, but not without costs. The paper summarises the current applications of inseam drilling, recent technological advances and the next generation survey and geophysical sensing tools which are currently being developed

Jan 1, 1998

By L. A. Henry

The island of Jamaica consists predominantly of Carbonate rocks which vary in chemical & physical characteristics. Currently these rocks are used for construction and road aggregate, landfill and as a raw material in the manufacture of cement. Over the past fifteen years the Geological Survey of Jamaica with assistance from a number of international aid agencies and the private sector have identified deposits of high calcium/high brightness limestones which have the potential to be utilized as a high quality filler and a number of other commercial applications. Geologically, these limestones are formed within the Eocene Swanswick Formation, the Oligocene Walderston-Browns Town Formation and to a lesser extent the Miocene Montpelier and Newport Formations.

Jan 1, 1998

By M. A. S. Martins, J. C. Guillaneau

Steady-state simulation has been proving its usefulness and efficiency in process design and optimization for many years. Steady-state simulation is a very effective approach for plant design since it enables a great number of hypotheses to be considered regarding flowsheet, equipment etc., the processing equipment and material handling equipment to be sized, and the configuration of almost optimal industrial plant to be attained in a very short time. This paper will present the basic principles of mineral process simulation methodology and some real case applications of their capabilities in several complex ores in Brazil.

Jan 1, 1998

By R. Scott

This article describes and evaluates the establishment of Kuyasa Mining including the search for a suitable deposit, the ongoing lack of finance, and market constraints. Despite the dramatic initial growth and success of their Ikhwezi Colliery near Delmas, Mpumalanga, Kuyasa?s experiences offer some sobering arguments for significant changes to mineral rights ownership, the attitude of financial institutions and government policy if South Africa is to have a dynamic and successful junior and small-scale mining sector.

Jan 1, 1998

By C R. Fountain, W R. Cannings

The zinc-lead-silver mineral resource at Lady Loretta ranks amongst the worldÆs richest when measured in terms of in situ metal grades. However, the project remains undeveloped 28 years after its discovery in 1969. The primary obstacle to development has been the fine and complex grain structure of its ores, which make flotation concentration inefficient even with fine grinding. The size and remote location of the deposit have also hindered exploitation. BUKA planned to directly fume the volatile target metals from the ore when it acquired the project. Intensive, post-acquisition modeling showed the innovative processing route to be uneconomic, notwithstanding high metals recovery and low waste content in fume product. Progressive modifications and supplements to the underlying fuming process enhanced economics and resulted in a new mine-to-metal processing route for zinc-lead-silver ores. The proprietary, three-stage BUKA Zinc Process offers technical, economic and environmental advantages. It is expected to find widespread application in the treatment of ores and residues. However, neither continued R&D nor application to Lady LorettaÆs currently delineated resource can be justified under prevailing market conditions. The objectives and results of each step in the process development sequence are outlined with reference to their impact on the commercial viability of the Lady Loretta project.

Jan 1, 1998

By Andre L. De Vegt

Hydrogen sulfide is an expensive chemical used in nickel, zinc and copper mining and metallurgical operations for selective recovery and concentration of metals, from leach water streams, acid plant blow down streams, refinery electrolyte bleeds and precious metal, plant bleeds. Hydrogen sulfide is either produced on site by catalytic reduction of elemental sulfur or transported to the site as liquefied hydrogen sulfide (H2S) or as a sodium sulfide solution (NaHS) Biologically produced hydrogen sulfide has economically very interesting, application possibilities in the mining and metallurgical industry. Converting sulfates from waste streams into usable hydrogen sulfide by biological reduction results in operational cost savings in existing lime treatment systems. H2S can be produced biologically for less-than $500/ton S. For the past ten years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove sulfate and heavy metals. The hydrogen sulfide produced is used for recovery of metals,, mainly zinc, from the ground water stream. The system has been operating since May 1992 treating a flow of 5000 m3/d. At Kennecott's Bingham Canyon Utah copper mine, a pilot plant started operation in November 1995 to develop the process for selective recovery of copper from leach water using biologically produced hydrogen sulfide from sulfate containing groundwater. Other pilot plants are operated at DOE's Pittsburgh Research Center and at Cominco Research focusing on selective recovery of metals.

Jan 1, 1998