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By Randal J. Barnes

Computer based techniques for solving the Ultimate Pit Limit Problem have appeared in mining literature since the early 1960's. The majority of papers pertaining to this subject can be partitioned into one of two categories: discussion of the pros and cons of a particular algorithm, or a case study presenting specific applications of an algorithm. Subsequently, there has a1 so been considerable debate concerning the best techniques between, essentially, two camps: those favoring the moving cones techniques, and those favoring the techniques which yield true optimal pit designs. The purpose of this paper is not to add to this debate, but rather to present a few new ideas (partially a new look at an old idea), which can be easily implemented to noticeably improve any ultimate pit limit approach independent of the particular algorithm used. These ideas fall under the heading of "bounding the optimum" (Barnes and Johnson, 1980).

Jan 1, 1982

By Sharad Mathur

The purpose of this paper is to present the benefits of high reactivity meta kaolin (HRM) in high performance cement-based systems. HRM, unlike other pozzolans, is manufactured from selected naturally occurring kaolin ore and carefully processed under stringent conditions to result in a consistent product with highly pozzolanic properties. HRM is an ultrafine pozzolan that enhances the mechanical properties (workability and strength) and chemical stability (durability) of Portland cement concrete and cement-based products. HRM is unique with respect to its white color which makes it an ideal choice for architectural applications where visual and aesthetic concerns are critical.

Jan 1, 2003

By Adolf J. Jonaitis

Outokumpu developed TankCell flotation cell technology beginning in 1990, following 35 years of successful flotation cell experience and application. In 1994, Outokumpu proved favorable operating success of 100-m3 (3,500-ft3) TankCells for porphyry copper and zinc flotation. In 1995, evaluation of a 150-m3 TankCell led to the successful application of these large cells in several operations. More than 350 TankCells of 100 m3 and larger in volume have been installed and are in operation. Key features of the Outokumpu TankCell design will be described. In addition, discussion of operating data from various metallic mineral flotation operations worldwide will be presented. Large flotation cell development continues today, with operating cell volumes of up to 160 m3 (5,500 ft3) in operation.

Jan 1, 1999

By Rodger E. Denison

The Middle Ordovician Simpson Group in the Arbuckle Mountains of southern Oklahoma contains sandstones of unusual purity. These have been exploited as glass sands since 1913 (Ham, 1945). Where quarried, the sandstones are uncemented or weakly cemented, greatly facilitating mining and processing. The origin: sedimentary setting, and lack of cementation of these valuable sands has been the source of much discussion. The lowest of the sandstone units in the Simpson is at the base of the Oil Creek Formation. The basal Oil Creek sandstone is exposed in a series of accessible quarries north of the town of Mill Creek in Johnston County. Virtually all conclusions and generalizations concerning origin of the Simpson sandstones are based upon observations made in these quarries. The three Simpson sandstones overlying the Oil Creek share many of the same distinctive qualities, and there is an assumption that they share a common origin.

Jan 1, 1999

By Kalliat T. Valsaraj, Louis J. Thibodeaux

A mathematical model is described for the transfer of hydrophobic compounds from aqueous to an immiscible organic phase using fine bubble aeration; the process otherwise known as "solvent sublation" an adsorptive bubble separation process. The limitations of the model are explored by simulating experimental results both for a batch scale process and a continuous process. The qualitative predictions of the model with respect to the influence of the organic layer (mineral oil) are tested by performing experiments using chloroform and 2,3,6-trichloroanisole as hydrophobic compounds in the aqueous phase. The continuous process is seen to be limited by the requirements of fine bubble generation and the ratio of influent feed rate to air flow rate.

Jan 1, 1989

By A. L. DeVegt, H. G. Bayer, C. J. Buisman

During the last ten years, Paques Inc. has been engaged in the development and installation of treatment systems to remove sulfur compounds from water and gaseous streams using biotechnological processes. Metal and sulfate can be removed from mine waters in two biological steps. In the first step, sulfate-reducing bacteria converts sulfate to hydrogen sulfide (H2S). The HS reacts with the dissolved metals to form insoluble metal sulfide precipitates. In the second step, sulfide-oxidizing bacteria convert excess H2S to elemental sulfur. The Budelco Zinc Refinery in The Netherlands installed a groundwater treatment system to remove metals and sulfate using the biological steps described above. The system has been operating since May 1992 and has been treating 5,000 m3/d (180 thousand cu ft/day). A pilot plant began operation in November 1995 at Kennecott's Bingham Canyon Utah copper mine to develop processes for metal and sulfate removal from groundwater and for the selective copper recovery from leach water. The principle of the biotechnological methods, the full-scale experience and an overview of the test program at the mine are presented

Jan 1, 1999

By G. A. Hope, K. Watling, R. Woods, I. Chandra, I. M. Ritchie

This paper presents two aspects of gold leaching research and development. The first section of the paper covers the development of innovative gold leaching processes. The research in this area has concentrated on the development of new thiosulfate leaching systems which use Fe(III) stabilized by ligands as the oxidant in place of copper(II)+ammonia. The second section will cover the development of innovative techniques such as surface enhanced Raman scattering (SERS) to study the leaching of gold in cyanide solutions. It will be shown that the use of in-situ SERS yields information which cannot be obtained using other methodologies.

Jan 1, 2005

By Milton E. Wadsworth, M. Ken Han

The kinetics of leaching of galena in hydrochloric acid solutions with sulfur dioxide gas have been investigated experimentally. The leaching method is then applied to complex sulfide concentrates to evaluate its selective leaching capability and to develop a new hydrometallurgical lead extraction process based upon the method. The leaching reaction follows a linear rate with an activation energy of 61.9,KJ/mole. The rate Is of first order with respect to the product [H+] [Cl-] . Excel lent selective leaching capability f s demonstrated and an attractive hydrometallurgical process flow sheet is proposed.

Jan 1, 1989

By E. J. Donovan, O&apos

The use of Dynamic Analysis techniques in the design of conveyor systems is extremely limited. The most frequent use of the technique is in large and expensive systems where the emphasis is on insurance against failure caused by catastrophic tension waves. This paper sets out to illustrate a much wider range of applications where dynamic analysis has been successfully employed. The examples chosen deal with identification and correction of dynamic low tension problems, the variability in take-up movement as other system parameters change, the requirement for proper tuning of starting controls and finally the absolute necessity for a complete understanding of the entire system when specifying brakes for critical applications. The intent of the paper is to get designers to view a conveyor as a system of interacting flexible components rather than as a single rigid body.

Jan 1, 1993

By M. Kumral

The in-situ mineral characteristics of a deposit are simulated by sequential co-simulation and averaging the simulated characteristics within specified block volumes creates a three-dimensional block model. This model is then submitted to optimal open pit and production scheduling algorithms. As the market values of industrial minerals depend on the satisfaction of predetermined blending criteria rather than metal content, a Linear Programming (LP) scheme has been used to identify all blocks that can be included in the blend without violating the grade requirements. The Lerchs-Grosmann algorithm using the blocks identified by the LP program determines optimal pit limits. All blocks that lie outside the optimal pit are removed from the system and the blocks within the optimal pit are submitted to the production-scheduling algorithm. Production scheduling optimisation is done in two stages: Lagrangean parameterisation, resulting in an initial sub-optimal solution, and multi-objective simulated annealing (MOSA) improving the sub-optimal schedule further.

Jan 1, 2002

By Christof Brewka

Los Pelambres, 200 km north of Santiago, Chile, is the latest in a series of mega-projects developed in this part of the world. While most of its predecessors are spread over open desert, the Los Pelambres mine is nestled inside a narrow alpine valley high in the Andean Mountains. To handle the daunting task of transporting the mined copper ore more than 12 km and 1,400 vertical meters downhill to the concentrator plant, a gigantic belt conveyor system (capacity of 8700 mtph, 1800 mm wide ST 7800 steel cord belt, 2.5m diameter pulleys, an elaborate braking system including a mechanical failsafe and large reducers with a total installed drive power of 25,000 kW) has been employed. Many of these components have pushed the limits of conventional belt conveyor design.

Jan 1, 2000

By Todd L. Hollingsworth, Jeremy K. Hobbs

In 2001, the Radomiro Tomic Mine located near Calamq Chile, added a tertiary crushing facility. An 84" wide mobile tripper is used to fill their tertiary crushing storage facility. This paper is a we study to demonstrate the drive and control systems in use on the tripper. Of special note is the design concept used to allow the system to operate multiple motors in both demand and regenerative modes through a single VFD. Also noted is the use of touch screen local controls, handheld radio controls, starting/stopping/ braking philosophies, safety device interfaces, and the local to remote control interface.

Jan 1, 2004

By Alex Harrison, Steve Kasper

Various countries around the world have testing and manufacturing standards in place for steel cord belting. These standards are very comprehensive in what they allow the end user to specify, however, their practical significance in terms of belt life is more difficult to quantify. Such testing standards will be briefly reviewed in this paper in relation to the implication for end user expectancy. Since there is no US standard of manufacture, the end user is left with writing their own specifications. In addition, such standards do not address the effect on belt life of manufacturing faults, such as cord plane buckles, or lateral cord movement. Some new technology used to test steel cord belting will be described as an aid to both manufacturer and end user. Specific end user related issues addressed on this paper are: Tracking and belt quality Cord plane irregularities and performance Cord size and belt life Cord fatigue and testing

Jan 1, 1993

By Martin L. Smith

Mine waste characterization and risk assessment currently focesses on water quality and largely ignores boththe charteristics of the wastes themselves and how wastes interact with the environment. Characterization of the parameters that control contamination of pore waters and their migration can quantitatively assess risk and remediation strategies in terms of cost effectiveness and risk reduction. Since mine waste characteristics are spatial, geostatistical methods should be used for characterization and assessment. A number of geostatistical methods are reviewed in terms of their application to mine waste sampling, modeling and risk assessment and management.

Jan 1, 1995

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 Kenneth N. Han, Xinghui Meng, A. J. Monhemius, G. W. Warren, E. Peters

The leaching of gold in ammoniacal solutions containing various oxidants in an autoclave has been investigated. Also studied are thermodynamic and kinetic aspects of the ammonia leaching of gold and silver. The variables studied included stirring speed, temperature, concentration of ammonia, ammonium, and various anions. Arrhenius activation energy values were found to be between 47.1 kJ/mol and 86.2 kJ/mol depending upon the kinds of oxidants used. An electrochemical reaction controlling mechanism has been proposed for the dissolution reaction. The leaching behavior of gold and silver from various ores in ammoniacal solutions containing various oxidants has also been investigated. The samples tested included sulfidic as well as carbonaceous refractory ores. The recoveries of gold and silver from these refractory ores were better than 96% within 2-3 hours of leaching time.

Jan 1, 1993

By D. W. Fuerstenau

The success of industrial flotation separations has been the design of specific chemical schemes for regulating the bulk and the surface chemistry of the system. Highlights of fundamental research on the nature of flotation reagents and their mode of action in flotation, which has been carried on for about the past 65 years, is briefly reviewed.

Jan 1, 1995

By D. C. Wilder

Deformations during heating and cooling of three drifts in granitic rock were influenced by the presence of faults and shear zones. Thermal deformations were significantly larger in sheared and faulted zones than where the rock was jointed. but neither sheared nor faulted. Furthermore. thermal deformations in faulted or sheared rock were not significantly recovered during subsequent cooling thus a permament deformation remained. This inelastic response is in contrast with elastic behavior identified in unfaulted and unsheared rock segments. A companion paper (Butkovich and Patrick, 1986a) indicates that deformations in un- sheared or unfaulted rock were effectively modeled as an elastic response. We conclude that permanent deformations occurred in fractures with crushed minerals and fracture filling or gouge materials. Potential mechanisms for this permanent deformation are asperity re-adjustments during thermal deformations. micro-shearing, asperity crushing and crushing of the secondary fracture filling minerals. Additionally, modulus differences in sheared or faulted rock as compared to more intact rock would result in greater deformations in response to the same thermal loads.

Jan 1, 1986

By Y. Théberge, V. Svalbonas, M. Fresko, E. Stopper

For many gearing applications, calculations carried out to AGMA standards are comprehensive. For very large gears, the elastic nature of the gear and pinion structures begins to play a larger role in determining the load distribution along the teeth. Various factors affecting the stiffness of the gear and pinion sets have been studied through FEA models for actual configurations. In particular, the effect of gear shape, load location, unsymmetrical structures, etc. have been studied in the unaligned and field aligned conditions. Analysis results show that the load distribution factor is highly sensitive to pin-ion stiffness, which affects gear structure design.

Jan 1, 2004

By Shibo Zheng, Zhengxing Gu, Zhizhong Gao

In recent years, beneficiation tests were conducted on high dolomite phosphate samples from Florida by the authors from China Lianyungang Design and Research Institute (CLDRI). The research results indicated that flotation is the most effective process for recovering phosphate from Florida high dolomitic pebble. Other operations like scrubbing, desliming and selective grinding might work to some extent, but they could only be applied as supplementary approaches in some cases. Heavy media separation and calcination-digestion technologies are hard to produce satisfactory performance. This paper presents the results of both lab scale and pilot plant tests on Florida high dolomite phosphate pebble using the fine particle flotation technology developed by CLDRI. Some discussions are made on the concerns of Florida phosphate industry and further research.

Jan 1, 2002