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By James H. Nulty, Joseph S. Roti

Wetting agents used for heap leach gold applications would appear to have technical merit in aiding in recovering higher levels of precious metal. Many questions, however, remain as to whether they will function in practice, on what type of ore are they effective and if there are any negative affects associated with their use. A series of experiments are conducted at Bateman Labs, Sparks, Nevada, to determine under what conditions reagents of this type are useful. Carbon kinetics test work was also performed to determine if there are negative aspects associated with carbon loading with the use of these treatment chemicals. This paper outlines the results of these research evaluations, the general chemistry associated with action of wetting agents on leach ores and future work which is planned to further determine the viability of these products in the mining industry.

Jan 1, 1998

By Tony Stephens

In this paper I will try to give an overall picture of the use of pure oxygen in gold leaching in South Africa. Pure oxygen has been overlooked as a reagent for many years. Only with the increased sophistication of gold plant instrumentation, greater recognition of the technical abilities of the plant management and a more definite attitude towards plant efficiency has the recent break-through been achieved. There are, today, twelve plants using pure oxygen in this way as a permanent part of their operation and another three or four presently carrying out long-term evaluations. I believe that this number will double over the next few years as more and more plants identify potential benefits. I have, therefore, set out to look at the background and chemistry behind these innovations, describe the various methods available to dissolve oxygen, briefly look at the laboratory and trial work carried out by ourselves at Afrox and then the different installations, both ours and those of our competitors.

Jan 1, 1998

By Jim Johnson

The purpose of this paper is to summarize and discuss a variety of site specific conditions which are typically evaluated as part of the engineering design process for heap leach pads, solution control ponds, and associated facilities. The following sections will focus primarily on the topographic, climatologic, hydrologic, and geotechnical evaluations critical to selection of heap leach sites, and selection of a preferred heap leach configuration or method. Other important considerations in the design of a heap leach project, including evaluation of ore properties and leachability, pregnant solution processing requirements, spent ore neutralization/disposal requirements, and other anticipated reclamation requirements are beyond the scope of this paper are not addressed in any detail.

Jan 1, 1998

By Rob Dorey

The disposal of mine waste continues to be one of the main controlling factors in the economics and feasibility of project development. Particular to gold and precious metal mining, waste disposal is further complicated by the environmental and political implications of the use of cyanide. Regulatory compliance criteria have partially dictated and can be anticipated to further dictate the approach and methods of tailings disposal. To develop practical, economic, and environmentally acceptable tailings disposal systems within these criteria requires the use of common sense approaches and the application of available technology. Waste disposal is typically considered during the pre-feasibility stages of project evaluation. At this time, the main emphasis is on the economics and practicality of extracting the metal values from the ore. Frequently, the result of this is that the nature of the tailings and the ability to dispose of the tailings is prejudged. It is also frequently the case, however, that during the feasibility stage and project permitting, the requirements for tailings disposal become paramount.

Jan 1, 1998

By J. E. Spencer

Mesozoic and Tertiary mineral deposits in west-central Arizona are commonly associated with Mesozoic thrust faults and Tertiary detachment faults, respectively. Quartz-kyanite rocks and pyritic quartz-sericite schists with local anomalous gold are the product of probable Jurassic argillic alteration of Jurassic volcanic, sedimentary, and plutonic rocks followed by Cretaceous thrust burial and associated metamorphism. Slivers and sheets of Paleozoic carbonates along Mesozoic thrust faults were locally sites of syn-and post-thrust mineralization. Widespread brecciation along Tertiary detachment faults resulted in increased permeability along fault zones. Elevated thermal gradients also resulted from detachment faulting and apparently caused convective aqueous-fluid circulation along detachment faults and associated Fe+Cu±Au mineralization.

Jan 1, 1988

By R. L. Grayson

An integrated approach to mine management is presented. A model for achieving the level of control of operations critical to surviving in the current market is outlined. The integrated Production and Cost Management System (PRaCaST) is designed to provide mine managers with a reliable, quantitative, decision-assisting system that can be used in formulating timely responses to complex fluctuations in operations. PRacaST consists of a productivity forecast model, sectional bills of materials containing current resources consumption factors, a linear programming scheduling model, and operations analyses that focus on production and cost performances. The system is applied to an underground coal mine.

Jan 1, 1988

By S. K. Vidyarthi

Most wastewater clean-up processes suffer from a fundamental lack of specificity in that a Reverse Osmosis process removes all dissolved solids, an Electrodialysis Reversal process removes all ions, wanted or unwanted, etc. Most techniques require the use of a membrane or contact surfaces that are prone to foul-up and are ineffective in situations where solids may be present. A photochemical process for the metallurgical industry on the other hand has the ability to operate specifically on targets that can range from one selected ion to an entire group of homologous species such as all biologically active species. Processes can be designed to change the oxidation states of a target altering the environmental impact. Several processes are currently in operation ranging from Cyanide removal to disposal of radiation wastes. This paper describes applicable photochemical processes with the help of certain key model examples.

Jan 1, 1988

By Rich Perry

HARRY HINDS: Our second speaker today is Rich Perry. Rich is the manager of leach and dewatering at Newmont Gold Company's Carlin operations. He has been the operator of Newmont's refractory leach development program for the past three years. Prior to joining Newmont in 1994, he was plant superintendent at the Big Springs and Jerritt Canyon Roasting Mills for Independence Mining Company. He graduated from the University of Nevada's Mackay School of Mines, and has lived with his wife and three children in Elko, Nevada, for the past 12 years. Please welcome Rich as he presents "New Facility Design Engineering: On-Site Versus Engineering Companies' Offices." RICH PERRY: Newmont Gold Company has been mining and processing gold ore at its Carlin, Nevada, operations since 1965. Processing is done using oxide milling, heap leaching, and whole ore roasting methods. Newmont began development of refractory leach processing technology at its research and development facility in 1988. The R&D staff focused on developing processing methods for low-grade refractory gold resources at Carlin that could not be economically processed by refractory milling methods. The term refractory ore refers to those ores that contain quantities of sulfides and/or organic carbon that result in low recoveries using conventional cyanide leaching. The R&D staff developed two potential processes deemed worthy of further testing: heap biooxidation to liberate gold occluded by sulfides and ammonium thiosulfate leaching for gold recovery from carbonaceous preg-robbing ores. These were piloted in small heaps by the staff of the R&D and Carlin metallurgical labs from 1990 through 1994. By 1994, Newmont's R&D and metallurgical staffs had unlocked the chemistry and kinetics of the two processes, and it was decided that the operations group would be brought in to begin development of a commercial plant. A project manager at Newmont's Denver office was assigned to the project. Scale-up issues such as biooxidation leach pad design; on/off heap heights; handling of various ore types during stacking and reclaiming; operating costs; and environmental, health, and hygiene concerns using a new process chemistry remained unanswered.

Jan 1, 1998

By Wang Xifu, Zhang Daxian, Zhang Youdi

In mine haulage system, the surge bunker or stockpile installed between two facilities can raise the system production capacity. The arrangement of surge bunker has great relation with the capability development of the whole haulage system and the economic benifit. In the haulage system, surge bunker plays a role of surge capacity, accident capacity and technology capacity. In this paper, the variation of the material in surge bunker is analysed while the mine haulage system is working, the calculation method of the whole output is raised. With the goal of the maximum system output, the method of deciding the rational size of surge bunker is put out. In case study, the system output in Huolinhe surface mine is calculated, thus the rational size of surge bunker in huaulage system is decided.

Jan 1, 1996

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 Franklin T. Matthias

No one involved in the contruction business wants litigation, except maybe some lawyers. Contractors rarely resort to litigation unless they have sustained econmic wounds that are serious or mortal. The major cause of serious contractor losses occur because of sub-surface conditions which cannot be defined with certainty in any practicable way except as shown during construction and prove during construction to be substantially worse and more expensive to cope with than anticipated during bidding. Building, Dam and Highway contractors are generally close in their estimates of cost after they get foundations excavated and are building above ground. Their main risk in bidding is the cost of getting out of the ground compared to their estimate. So maybe 10%, 20% or even 30% of their project represent high risk underground work. The tunneling and underground contractor is dealing with high risk work for virtually 100% of his project. He appreciates this risk and is willing to assume it up to a bearable limit. His costs are highly sensitive to relatively small variations of the ground in underground work. His work is unique in other respects. As contrasted with other types of construction where loads develop as construction progresses and do not reach ultimate until the project becomes operative, tunnel and underground construction requires the immediate structural support of ultimate loads that are there when he digs or very soon thereafter. He must put in enough support

Jan 1, 1974

By Dillon Tew, Kush Chohan

N/A

Jun 13, 2021

By W. Hennig

Efforts to define sustainability indicators are continuing in the mineral extracting industry and sector research institutions. Comprehensive ‘sets’ of economic, ecological and social sustainability indicators for the minerals industry are a necessary precondition for rationale-based negotiations with stakeholders from society. These tools alone, however, will not suffice in a delicately balanced economy-ecology -social well-being equilibrium with ever shifting valuation of different variables. Individual interests and emotions and also ideologically motivated positions of diverse stakeholders are gaining momentum. The minerals industry therefore has to develop beyond the rational pro-arguments for mining in the form of sustainability indicators also proactively its ‘soft skills’ to deal with expectations, fears and outright anti-mining bias, if it wants to retain the ‘social licence’ to continue.

Jan 1, 2005

In general, it cannot be assumed that the strength of coal pillars remains constant over long periods of time. Field observations indicate that a coal seam, especially when it contains a parting layer, deteriorates over time, reducing the load-bearing capacity of the pillars. This paper discusses a unique approach to determining the time-dependent strength of coal pillars in the field. Three coal pillars that were developed 5, 15, and 50 years ago were chosen for the study. Holes were drilled in coal and parting layers in each pillar, and the strength profiles were determined for each hole using a borehole penetrometer. The strength data were treated statistically to establish time-dependent strength equations for different layers. The results can be used to help estimate the loss of pillar capacity over time.

Jan 1, 2012

By T. O. Price

In 1969 Holosonics designed and developed a portable system for conducting acoustical surveys in metal mines, with lead-silver veins as the principal targets. Recently this system has been proven useful in describing rock structures for advance geologic information in civil engineering application and underground construction applications. This paper discusses a case history of acoustical surveying from a series of pilot drill holes in an advancing tunnel. In acoustical surveying a pulsed acoustic signal is used to generate reflected signals from the rock formation. Arrival time, amplitude and phase of the returned signals can be determined. These data became the basis for a signal correlation program designed to relate the signals to their respected pseudo-planar reflecting interfaces. An application of acoustical surveying has recently been conducted in a portion of the excavation for the Washington Metro Area Transit Subway. The data results and conclusions of the program are discussed in the paper. Acoustical surveying was successful in predicting the occurrence of major jointing and foliation plane shearing ahead of the tunnel advancement.

Jan 1, 1974

By R. Pakalnis

A comprehensive project has been completed at the University of British Columbia that focused on the development of a commercially competitive composite cable bolt. Laboratory evaluation consisted of pull tests, preliminary shear tests, grout column testing and scanning electron microscope evaluation of the composite cable bolt. Field implementation at five underground mines throughout Canada were completed for technical and overall performance evaluation of the new product. The project began in 1989 under the sponsorship of HDRK Ltd., a consortium of mining companies including Inco, Noranda and Falconbridge Ltd. The objective was to develop a cuttable cable bolt that would serve as support for a continuous miner within a hardrock environment (Mah, 1994). The bolt was required to be cuttable by a continuous roadheader without adverse effects to equipment, personnel and the milling process. From the beginning, the focus was to employ existing cable bolt installation technology (Goris et al., 1994) whereby the cable bolts are grouted within a 4.8-cm-diam (1.08-in.diam) or larger employing a portland cement grout having a water:cement ratio between 0.35:1 to 0.4:1.

Jan 1, 1994

By I. Douni

In the last decade there is a growing interest from the society about the rational use of raw material resources and the minimization of the environmental impact of production processes and products when they reach the end of their life cycle and are disposed in the environment. In order to respond to this societal request industrial and scientific community have made considerable effort to optimize the environmental performance of the production processes and products and also to develop the necessary tools to quantify the environmental impact over their entire life cycle. In this framework the methodology of Life Cycle Assessment (LCA) has been developed about fifteen years ago and since then it has become a widely acceptable tool to quantify and assess the environmental impacts. The application of the LCA methodology can significantly assist the mining and mineral processing sector in the development of a strategy concerning the rational exploitation of raw material resources, the management of solid and liquid wastes and the optimization of the metal and mineral production processes. In this paper the work that is currently being done in the Laboratory of Metallurgy of the National Technical University of Athens concerning the Life Cycle Analysis of the production processes of basic metals, as copper, nickel, lead, zinc, aluminum etc is presented.

Jan 1, 2003

By A. J. Hendron, G. Mesri, R. M. Semple

Squeezing ground conditions in hard-rock tunneling are associated with fault zones containing brecciated rock and gouge. Gouge is a stiff clay-like soil that exhibits a propensity to creep. The ground loads applied to tunnel supports in squeezing ground are known to be significantly time dependent. Accordingly, an experimental and analytical study is presented that deals with soil creep and its application to the prediction of tunnel support requirements in squeezing ground conditions. Relatively undisturbed samples of fault gouge obtained from Straight Creek tunnel in Colorado and Pacheco tunnel in California are classified as very stiff to hard clays of low plasticity. Constant-load undrained triaxial compression tests are performed on these materials. A simple, three-parameter creep equation is developed that adequately describes the observed deformation of fault gouge with respect to applied stress and time. The equation is shown to fit existing creep data of various soil types. The creep equation is used to modify an existing continuum-mechanics solution to the time-dependent behavior of unlined and lined cylindrical openings in a creepsensitive medium under a hydrostatic state of stress. Assuming properties for the medium that are representative of the fault gouge materials tested, parameter studies are performed for unsupported and supported tunnels in squeezing ground. The analyses permit estimates to be made of the steel set supports required for tunnels at different depths in various squeezing ground conditions.

Jan 1, 1974

By R. J. Sawyer

*An earlier version of this paper was presented at the IMM meeting, "Use of Cultivated Carbon in Extraction of Gold and Other Metals," held in London in January, 1983, and was subsequently published in Trans. IMM (Sect. C: Mineral Process. Extr. Metall.) in December, 1983. Reprinted with permission of The Institution of Mining and Metallurgy, London. INTRODUCTION This paper describes the development of the processing route for the Alligator Ridge Mine which commenced operation in 1980. It also reviews the modifications which have been made to improve operating efficiency during the three years that the mine has been in production. Alligator Ridge is located 70 miles Northwest of Ely, Nevada. The mine is a joint venture between Amselco and Nerco with Amselco acting as operator. The deposit consists of micron sized disseminated gold imbedded in siltstone. Although definitive conclusions have yet to be drawn as to the age and origin of the deposit, it is probable that it is young by geological standards, perhaps only 5 million years old. It is likely that the gold was brought to the surface by hot springs. As the superheated solutions rose through the porous siltstone, they redeposited minerals in the rock, forming the present ore bodies.

Jan 1, 1984

By Gus Van Weert

Capital and operating costs for a 10 tpd NITROX PROCESS® demonstration plant are being established. The flowsheet is based on Dickenson Mines' Red Lake arsenopyrite concentrate. Support for the work comes from a number of mining companies, engineering firms and the Northern Development fund of the Ontario Government.

Jan 1, 1998