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By Gerald W. Longenecker

For decades, traditional hydraulic engineering approaches have been used for sizing stream channels when stream relocation efforts have been necessary to allow for the advancement of quarry and other surface mining operations. These approaches have been based on various ydraulic models to design channel cross sections and slopes that could pass the required regulatory design storm such as the 2-, 5, lo-, 25-, 50-, or even loo-year events. Designing the stream channel to handle these more extreme ,storm events would often lead to large channel designs which required extensive bank and channel bottom stabilization techniques including concrete, rip rap, gabions, or other expensive approaches. The constructed channels often required ongoing maintenance to remove accumulated sediment and other debris which would settle out and reduce the hydraulic capacity of the channel.

Jan 1, 1998

By P Grieve, J L. Mauk

The Central Maratoto Valley in the Coromandel Peninsula contains a sequence of veins in pervasively altered dacite + andesites of the Waipupu Formation. We recognise at least eight different vein types: (1) pyrite stringers, (2) quartz + carbonate veins, (3) crystalline quartz veins, (4) carbonate veins, (5) chlorite + carbonate veins, (6) siderite veinlets, (7) siderite + carbonate veins and (8) carbonate + pyrite veins. The overall temporal trend of the veins is from early pyrite to quartz and then to late carbonate veins. Carbonate veins and pyrite stringers both form planar and irregular veins, whereas some carbonate veins have diffuse contacts with the wall rock. Gold and base metal sulphides are associated with some of the quartz + carbonate veins. Textures within the veins reflect open space filling and multi-phase reopening. A partial record of hydrothermal activity has been preserved by vein crosscutting relationships, hydrothermal alteration minerals and fluid inclusions. Hydrothermal alteration minerals display zonation from south to north. The alteration increases from unaltered to weak propylitic alteration of andesite in the south (MVRCDC1), to sericitic alteration of andesite and dacite in the north (MVRCDC3). The alteration assemblage is dominantly sericitic, with no adularia present, drawing parallels to the Thames region where there is no adularia.

Jan 1, 1999

Diesel Particulate Matter (DPM) is considered carcinogenic after prolonged exposure. With increasing use of diesel-powered mining equipment in underground mines, miner?s exposure to DPM has been increasing. Most studies on the issue has been DPM control measures with few studies on diesel exhaust propagation patterns after leaving the tailpipes. This study uses computational fluid dynamics (CFD) to investigate the airflow pattern in an underground metal/nonmetal mine for a single heading. Several high DPM concentration areas are identified in the study and common practices for compliance are suggested. Airflow and DPM distribution are compared between blowing and exhausting face ventilation systems. Suggestions are also provided for the protection of miners in the face area.

Jan 1, 2009

By M. Schafer

The 20 foot diameter cast-in-place tunnel lining for Phase 3 of the Mill Creek Tunnel (MCT-3) has been completed. This paper will summarize aspects of liner design and address the construction approach in placing the liner in areas of tunnel that experienced crown overbreak. Tunnel lining production rates, installation procedures and form buoyancies experienced during concrete placement will also be presented.

Jan 1, 2008

By M. D. Khattar

Problems discussed concern encountering of high temperatures [up to 66°C] and heavy flow of water [150 L.P.S] during the construction of the 10.15 MØH.R.T. for the 2500 MW Nathpa Jhakri Hydro Power Project in the Himalayas(India). Over a length of 2500 M progress of work got seriously affected resulting in excessive time for completion - two years [max. monthly progress achieved was 178 M [Heading]. Many innovative and simple steps were taken to complete the work in these inhospitable environs affecting working of both men and machines. Also it meant a review of the design of concrete lining. Other geological conditions affecting the progress are also described.

Jan 1, 1999

By Miguel A. Farfán

El presente trabajo describe los criterios de productividad en el diseño de tajeos para vetas irregulares a través del método de explotación de corte y relleno. Dicho método es factible -en tanto es capaz de captar el desmonte producido por niveles superiores que requieren avances, así como también en los inferiores. De forma que se pueda agregar valor por la función que cumple en la producción sino por las demás actividades. Finalmente, en el caso de los índices de productividad, el control se debe manejar a un nivel de planeamiento que pemita corregir procesos muy costosos, faltos de continuidad y genere equipos parados, tiempos muertos, daño a equipos o recursos.

Sep 12, 2005

Developments in the technology of explosive production and deliveryallow a greater amount of flexibility in rock fragmentation by blasting. The rock fragmentation efficiency of an explosive is currently given by a rating which is determined by the explosive manufacturers using proprietary formulae and methodology. Hence, comparison of explosives from different manufacturers may be misleading. Modeling of explosive energy, using a thermochemical code such as CHEETAH provides an objective standard by which the likely performance of different explosive formulations can be determined. Such modeling can be used for optimisation of explosive composition to match specific rockfragmentation objectives.

Jan 1, 2001

By A D. Campbell, G R. Power

Many caving mines use numerical flow models to simulate mine production, forecast recovered ore grades and optimise the draw strategy. In sublevel caving (SLC) mines, the effects of blasting and fragmentation at an individual ring scale generally cannot be included in these models. Previous attempts to use results from marker recovery trials to calibrate numerical flow models have been limited due to difficulties in accounting for blasting effects at a ring scale. This paper outlines how an empirical criterion for blasting and fragmentation was used to attribute variable flow properties into a numerical flow model based on the blast design and modelled fragmentation. The flow model was then validated using data from a number of full scale marker recovery experiments. The result of this approach was a significant improvement in forecast accuracy when compared against the same modelled cave marker recovery without the inclusion of these blasting effects. Improvements in the flow model are currently being adopted within the mine scale model to further improve the accuracy of grade forecasting, optimise the draw strategy and increase net present value. The integrated modelling approach is also being used to simulate the effects of different drill and blast designs on cave recovery. It is suggested that, if implemented, the technique would lead to improved blast designs in other SLC mines, increase the value of marker trial data and reduce costs associated with large scale blast design trials.CITATION:Campbell, A D and Power, G R, 2017. Improving calibration of flow models against SLC marker trials by linking blasting effects to particle mobility, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 11–22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By A. H. WHITE, PERRY BARKER

In a consideration of the various means whereby more economical and more efficient use may be made of the fuels in the United States, the possibility of obtaining for the production of illuminating gas other and cheaper fuels than the Pennsylvania coals demands attention. For the Government, as well as for private corporations and the householder, there can be no more economical and efficient way of using some coals than through the medium of illuminating gas. In the stove, gas reduces the labor cost of heat production and lessens the drudgery of the kitchen; burned in the Welsbach mantle, it is an excellent and cheap illuminant. In addition, the coke that remains after the gas has been recovered furnishes a smokeless fuel that has about the same heating value as anthracite. Hence any investigations that will indicate how local coals through proper treatment may be substituted for the higher priced and rapidly vanishing Pennsylvania gas coals will bring about lower prices for both gas and coke and will also aid to conserve for use in metallurgical processes the coking coals of Pennsylvania and of ot,her States. The annual drain on the gas-coal resources of this country and the importance of the gas and coke industries are indicated by the fact that 8,390,129 tons of coal were carbonized in retorts in the United States in 1909. The resulting salable products from by-product ovens were 15,791,220,000 cubic feet of coal gas, 6,254,644 tons of coke, and 60,126,000 gallons of tar. The total value of all by-products was about $28,508,637.

Jan 1, 1911

By Robert F. Randolph, Jeffery L. Kohler, David C. Byrne

Multiple versions of an educational message can reach a diverse population more effectively than a single version. For instance, some workers are trained in formal classrooms while others are self-taught. The National Institute for Occupational Safety and Health has developed multiple versions of a hearing loss simulator (an interactive software package, a Web-based module, and an electronic slide show) to show how a single set of information can be readily adapted to different delivery methods. The three versions of the simulator were developed with a minimum of effort and expense compared to a single, less-flexible version. The interactive software is best for training sessions led by a hearing conservation professional, the Web pages are best suited for an individual worker, and the slide show is best for a small, more-generalized, training class. This paper will describe additional advantages and disadvantages of different delivery systems and will show what considerations are helpful in designing content that can be readily adapted to alternate presentations.

Jan 1, 2002

By T. Mills, M. Evatz

Newmont’s Lone Tree Mine, located in northern Nevada, is an open pit gold operation supported by a standard truck and shovel mine production fleet (Caterpillar 785Bs and Hitachi EXs). Newmont continues to search for ways to decrease capital expenditure and lower operating cost, hence the implementation of the Ultra Light Body (ULW) concept. The fundamental idea associated with the ULWs is the increased payload potential. Economic justification comes from successful achievement of additional payload, within the truck’s rated GVW, without changing its loading and hauling characteristics. The increase in payload capacity allows equivalent tonnage movement using fewer trucks.

Jan 1, 2001

By Y. Wang, E. Forssberg, A. Johansson, B. Chan

A super-conducting high gradient magnetic separator with matrix vibration in dry separation mode is a powder purification device, which has been used to remove weakly magnetic impure particles from fine calcite powders below 53 µm in this study. A fundamental question concerned is the evolution of the matrix clogging under gas-solids loads. This paper presents the improvement of the separation selectivity using a method of mechanically based vibration on the matrix in the separator. The functions of the matrix vibration are discussed. The results indicated that the mechanically based vibration on the matrix within a high intensity magnetic field while a feed was introduced in an air stream, was found to be effective for the dry purification of fine powder materials.

Jan 1, 2001

By L Olivier, R J. Lowther, J L. Lett, I Brunton

Hydraulic fracturing to precondition the orebody to enhance rock mass cavability is gaining acceptance in underground cave mining applications. Assisting cavability is becoming important as an increasing number of cave mines are being implemented in hard, deep and competent rock masses where clamping stresses are higher and cave column heights may be in excess of 1000 m. Propagating large caves to surface in such conditions can be challenging as risks such as slowed propagation and air gaps can develop during the process.Underground-based hydraulic fracturing is routinely used at Cadia East as a means of preconditioning the orebody to assist in cave propagation, fragmentation and seismicity reduction. This paper presents a summary of a surface-based hydraulic fracture program that was successfully implemented to assist in the propagation of the Cadia East Panel Cave 1 (CE-PC1) cave to surface through competent overlying rock masses. In this case study, the propagation of the CE-PC1 cave slowed as the cave grew past 750 m in height, initiating a Trigger Action Response Plan regarding the cave propagation rate. Surface-based hydraulic fracturing was subsequently used to stimulate the cave to propagate through the final 450 m to surface. The paper details the equipment, strategy, implementation and risk management involved in the program as well as the key learnings.CITATION:Lowther, R J, Olivier, L, Lett, J L and Brunton, I, 2016. Implementation of a surface-based hydraulic fracturing program to successfully propagate a large cave through hard, competent near-surface rock masses to achieve breakthrough, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 83–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By W. A. Ahrens, J. H. McNamara, J. G. Franek

"An economical, pollution-free process has been developed for the hydrometallurgical extraction of copper from sulphide ores. The extracted copper, in the form of cuprous chloride (CuC/), is converted by reduction to copper metal. The metal is melted and fire -refined into wire bars which meet the standards of electrolytic tough pitch (ETP) copper wirebars. IntroductionThe successful development of the Cyprus Copper Process has been an evolutionary series of events covering a time span of some nine years. The original process, based on an electrolytic membrane cell principle , was abandoned in 1975 because of technical, economic and pollution problems. During the past four years, the pilot plant has been reconstructed based on a new flowsheet and operated successfully in several campaigns, some for as long as four months. The pilot-plant hydro section operates at a 225-lblhr copper rate. In October 1977, a feasibility study was completed by Jacobs Engineering, Pasadena, California. The study showed favourable economic and technical feasibility. Jacob's studies in 1978-79 revealed favourable comparative economics with other known pyrohydro processes and favourable economies of scale.The Cyprus Copper Process converts copper concentrates of varying composition into copper metal, which has been proven to be equivalent in every way to electrolytic tough pitch copper, suitable for electrical applications. This is accomplished at capital and operating costs which are estimated to be lower than those associated with any other known currently applicable technology. Also, the total energy requirement is equal to or less than any other known process and the process is essentially pollution free."

Jan 1, 1980

By V. I. Lakshmanan

Process Research ORTECH Inc. (PRO), with its in-depth knowledge on cobalt behaviour in nickel matte smelters and its novel mixed chloride hydrometallurgical processing, is developing a hybrid process to enhance cobalt recovery. PRO’s experimental data is compared with plant information on cobalt behaviour in smelters. In final stages of iron rejection in the converters, the thermodynamics of the matte-slag system dictates the undesirable transfer of the cobalt to the final converter slags. This results in much lower cobalt recovery in the product Copper/Nickel matte (<60%) in present copper and nickel smelters. This information is used to transfer cobalt into desired quantity of converter slag. The enriched cobalt slag is subjected to PRO mixed chloride process to recover nickel, and cobalt as high value salts of importance in lithium ion batteries. From a typical converter slag containing 3.5% Ni, 1.5% Co, and 1.0% Cu, PRO leach process extracts 98 % Ni, and 98 % Co, and 99% Cu. Application of this process to enhance cobalt recovery in typical Copper/Nickel smelters is presented. In addition, this will also enhance the Copper and Nickel recovery. Both these aspects are of interest to the Copper, Nickel, and cobalt producers. INTRODUCTION In pyrometallurgical extraction of copper and nickel from sulphide ores cobalt often occurs with copper and nickel. The requirement of cobalt is increasing due to its need in lithium ion cells used in electric vehicles. Therefore its efficient and economical extraction in a form suitable for use in lithium batteries is of great interest at present. In the pyrometallurgical processing of copper and nickel sulphide concentrates the concentrate is smelted to produce a furnace matte, which is then sent for converting to remove the iron to produce iron free (~1% Fe) matte for further processing to copper or nickel matte. The copper/nickel matte is processed for metals recovery by hydrometallurgical or vapo-metallurgical or oxidation – reduction routes to make market products. As shown in Figures 1 and 2 the slags are produced in the smelting step and in the converting steps. The metal losses in smelting are controlled by the oxygen pressure in that step and slag production which is controlled by concentrate grade. The slag produced in the converting step which is carried out at a higher oxygen pressure contains higher level of metals is often returned to the smelting step to increase value metals recovery.

Jan 1, 2019

By D. P. Harris

This paper examines recent developments and work in progress on the application of quantitative methods and computers to the appraisal of the mineral resource potential of discrete areas by employing reconnaissance geological information and general economic relationships. The perspective of this paper might be that of a firm planning a regional exploration program or of a legislative body seeking to choose between several alternative actions on the basis of their impact upon the regional resources. In addition to this general survey and commentary, an example is presented of the use of geostatistical analysis and computer simulation to evaluate the economic mineral resources of the Seward Peninsula of Alaska.

Jan 1, 1969

By J. K. Afidenyo, J. Osei-Owusu

"The Obuasi Mine of AngloGold Ashanti Limited has been operating the world’s largest Biooxidation Plant at its Sulfide Treatment Plant (STP) in Ghana, using the Gencor Biox® technology since February 1994. The Biox® technology was preferred to other alternative methods of treating refractory sulfide ores such as roasting, pressure oxidation and nitric acid leaching due to among other reasons, its lower capital and operating costs, reduced technical risk, relatively benign environmental impact and its ease of operation and maintenance in a remote location.STP has since commissioning succeeded in operating this technology successfully but not without some operational problems. The Plant has seen a number of upgrades and modifications in its circuits which were motivated by cost, operational and throughput constraints.The objective of this paper is therefore to highlight the mine’s experience in the treatment of its complex carbonaceous refractory sulfide gold ores with emphasis on plant operations and improvements such as the Biox® reactors expansion, flotation concentrate upgrade project and neutralization circuit modifications. The Biox® Plant operating cost is also discussed.INTRODUCTIONThe Obuasi mine forms part of the AngloGold Ashanti Group of Gold Mines. It is located in the Adansi West District of the Republic of Ghana. The mine is primarily an underground operation, although some surface mining still takes place. Ore is processed by two main treatment plants: the Sulfide Treatment Plant (for underground ore) and the Tailings plant (for tailings reclamation operations). A third plant, the Oxide Plant, is used to batch-treat remnant opencast ore and stockpiles, of which there are adequate tonnages to keep the plant operational until 2008.Though reference is made in this paper to the Tailings and Oxide Treatment Plants, the main focus will be on the Sulfide Treatment Plant."

Jan 1, 2008

By Anthony M. Opyrchal

This Bureau of Mines study assesses the economic significance of the Florida phosphate industry to selected counties in Florida, the State of Florida, and the Nation: it also includes a brief survey of the industry&apos;s international impact. Based on forecasts of Florida phosphate production in 1981, and using constant 1977 dollars. estimates are given for 1981 for regional and national output the value of this output, income, and employment created by the phosphate industry in Florida, Federal, Stale, and county tax revenues generated by the State&apos;s phosphate industry are also estimated for 1981. The concentrated impact of the phosphate industry on certain areas of Florida and on the State?s regional industries is examined using economic base analysis complimented by an industrial complex approach. The industry&apos;s impact at the Stare and national levels is examined through input- output analysis. In addition, an attempt to forecast for 1990 the effects of constraints on phosphate rock mining as a result of economic conditions and other factors is included as an appendix to the report. Also discussed is the phosphate industry&apos;s importance to the U.S. balance of trade: U.S. agricultural production. Including forward linkages; the U.S. sulfur industry; and the phosphate industry&apos;s importance to the production of fluorine and uranium by- products from fertilizer manufacturing.

Jan 1, 1981

By Robert Hopler

Earthquakes, ground vibrations, seisms, or whatever you want to call the shaking of the earth, have been a fact of life throughout time. In spite of this, most people (except those unfortunate enough to live in seismicallyactive areas) have probably never felt this phenomenon, or if they have, only a very few times in their entire lifetime. However, when it does happen, nothing is more frightening than the sudden shaking of the earth beneath us - after all, we think of the ground we walk on as the unyielding, solid underpinning of our existence.

Jan 1, 2006

Myths and misconceptions regarding cyanide in the mining industry are common. This is not surprising, given the other uses to which cyanide is, and has been put. Unfortunately, the economic benefits, largely due to the introduction of cyanide in towns such as Waihi are often unrecognized. In the current "green" environment, the New Zealand mining industry faces constant scrutiny and challenge. The use of cyanide in hard rock mining is one area which can stir the emotions of the public. &nbsp; Cyanide can be transported, stored, used and disposed of in a safe manner. The modem mining industry has an excellent record regarding the safety and environmental issues relating to cyanide. Many of the fears relating to cyanide in the mining industry have proven to be unfounded. It is important that this reputation is maintained. This is possible given proactive and ongoing management of cyanide issues.

Jan 1, 1997