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By R. Dorey

The Kennecott Ridgeway Mine in South Carolina is scheduled to complete mining and ore processing in the last quarter of 1999. Tailings are disposed in a 300 acre, lined tailings impoundment. To facilitate closure and reclamation, modification of the tailings impoundment operation has been adopted. Mining involved the sequenced development of two open pits. In 1996 mining of the South Pit was completed and backfilling of the pit with waste rock from the North Pit was initiated and will continue until mining ceases. Both pits will be reclaimed as fresh water lakes. This paper presents the physical, geochemical and hydrogeochemical evaluation of the operational and post operational management of the project. Comparison of the operational monitoring data against predicted performance is reviewed.

Jan 1, 1999

By Brian R. Zuckerman

The Capitol Area East End Complex is currently being constructed under contract with the State of California Department of General Services on two sites adjacent to the grounds of the California State Capitol Building in downtown Sacramento. The complex will consolidate the headquarters of the Departments of Health Services and Education, which currently occupy several facilities located throughout Sacramento. When completed in 2003, the complex will be the largest civic office project in California history, with approximately 1.5 million square feet of office space and housing nearly 6,300 state workers. The total project is being constructed on five separate blocks in downtown Sacramento, Blocks 171 through 174 and 225. Separate design/build contracts were executed for the construction on Blocks 171 through 174 and the construction on Block 225. The scope of this paper is limited to construction on Blocks 171 through 174, which comprise a square, two blocks on a side, bounded by 15th, 17th, L, and N streets, located immediately to the east of Capitol Park and the State Capitol Building, as pictured in the image shown below.

Jan 1, 2002

By J. Walker, G. E. Kim

Since May of 2000, Mogas Industries, in partnership with F.W. Gartner Thermal Spraying Co. and using the services of Perpetual Technologies, has invested time, energy, and resources towards developing novel ball valves for high-pressure acid-leach (HPAL) service. In addition to developing new valve designs, an aggressive coatings development effort has been undertaken to improve the protective quality of the coatings so as to enhance the performance and extend the life of valves in severe HPAL conditions. In 2001, Mogas Industries qualified and applied a nanostructured titanium oxide (n-TiO2) coating for gold and nickel/cobalt HPAL services. The n-TiO2 coating provided dramatically superior protection against abrasive and erosive wear, fared very well against high-pressure autoclave corrosion testing, and has performed well in HPAL service.

Jan 1, 2004

At Pasminco Mining's South concentrator. which was commissioned in 1952. an expansion. modernisation and efficiency improvement program commenced in 1986 with a coarse ore stockpile and grinding circuit expansion. the replacement of small flotation cells and the upgrading of reagent mixing and metering equipment. The program continued with the installation of a TDC 3000 based process control system (1988) and concentrate thickeners (1990). By mid-1991 a further grinding expansion and the installation of zinc flotation feed regrind ball mills and zinc recleaner column cells will be complete. leaving the use of ceramic disc fillers and development of process control strategies as probably the remaining major avenues for improved process efficiency at present.

Jan 1, 1991

By M. Rehor

The importance of brown coal as a raw material is currently given by growing energy needs of Czech Republic. More than 70% of mined brown coal comes from North Bohemian Basin these days. Mining of brown coal is run in four mining locations. They are geologically different and the parameters of mining coal are quite different too. This requires a little bit different methodology of both extraction and reclamation. Methods of reclamation works in the region are given mainly by the characteristics of overburden rocks appearing in the upper horizon of recuperated localities. The difficulties of the North Bohemian mine dumps reclamation works are caused by extremely unfavourable properties of rocks poured down to the majority of mine dumps. These are mainly rocks of the overlaying strata and the rocks strata of brown coal bed. Main materials poured down to the mine dumps are sands, clayey sands and kaolin ? illitic clays. Admixtures in filled rocks consist of organic (coal) mass, siderite and pyrite. These rocks are mechanically instable with respect to the wind and water erosion and during weathering they are getting unfavourable, acid (phytotoxic) nature, due to the influence of SO3 and Al ions. External and internal dumps of open pit mines are significant part of the North ? Bohemian landscape sustained by excavation. Their as fast as possible preparation and gradual integration into ecosystem of the area is interest of both citizens of region and mining companies. The paper briefly summarizes the methodology of restoration of the largest dumps of the North Bohemian Brown Coal Basin and the results of analyses and evaluation of samples taken on restored localities Rado-vesice dump, Strimice dump, Ru?odol dum pand internal dump of Bilina mine. An example of modern non-tradicional restoration methods is the restoration of internal dump of Bilina mine (application of power plant stabilizer). According to observations and results of sample analyses the methods of restoration were selected to limit the erosion influence, adjust the chemical and physical composition of surface of Radovesice and Strimice dumps. The application of marlites and bentonite prevent the unfavourable weathering processes on dump surface. Compensation of Quaternary sediments was artifically formed here. The need of marlite ploughing in, application of organical substrates and vegetation preparation was proved on Radovesice dump. The conception of landscape reclamation of the largest dumps after finishing of mining, methodology of technical reclamation and well considered using of fertilizable soils are main results presented in this article.

Jan 1, 2014

By L. Hansen

Sulphuric acid plants now and then see unexpected increases in SO2 emissions. Our experience is that it is not always easy for the acid plants to pinpoint the exact reason for the SO2 increase. Sometimes a catalyst bed is sacrificed even though reliable temperature readings and gas analyses could have verified satisfactory activity. Hence the leaking heat exchanger is never discovered and after the shutdown the SO2 emissions are still too high. This paper will look into some basic catalyst management tools: good record keeping is a necessity for collection of representative catalyst samples; reliable operating data is an inevitable starting point for all analysis; and trending of operating data is a must for plant optimization and troubleshooting. In addition, these catalyst management tools will give continuous updated knowledge of the catalyst status in each bed, providing the basis for a more effective replacement strategy. The most typical reasons for increasing SO2 emissions will be presented together with easy guidelines for cross-checking operating data, temperature optimization and good record keeping.

Jan 1, 2009

By Redhead Robert J.

"In 1991, the Canadian Council of Ministers for the Environment (CCME) charged its Waste Management Task Group with developing a nationally coordinated strategy to measure, monitor, and achieve the objective of decreasing the generation of waste (solid and hazardous) by50% from 1988 levels by the year 2000.With the encouragement of the CCME, which viewed hazardous waste as largely an industry problem, a committee, the “Industry Action Group”, representing eleven industry trade associations with a strong interest and involvement in hazardous waste was recruited.The Municipality of Markham, Ontario was also recruited (Appendix 1)."

Jan 1, 1996

By John C. Nigro

This Bureau of Mines report summarizes the performance characteristics of a 30-day around-the-clock gasification-pelletizing test conducted in October and November of 1980 with North Dakota Indianhead lignite. Gasification was conducted in a commercial-size, 6.5-it-diam, Single-stage, fixed-bed, atmospheric pressure producer with a rated capacity of about 30 million Btu/hr. Iron oxide pellets made from a commercial hematite concentrate were fired with the low-Btu gas in a 2.8-ft-diam by 35-ft-long pilot plant rotary kiln at a rate of 900 lb of pellets per hour. Gasifier operations at fuel feed rates up to 3 tons of lignite per hour and hematite pellet induration with raw 160-Btu/std ft3 lignite gas are described.

Jan 1, 1982

By L. E. Djingheuzian

"IntroductionIN 1940, in a series of articles, M. W. von Bernewitz(l) reviewed in detail roasting of gold and silver sulphide ores and concentrates. Since that time some significant developments in roasting have taken place, and a number of papers have appeared in the Canadian technical literature, dealing severally with the roasting of a particular ore or concentrate.The purpose of this paper is not only to review some of these Canadian papers and bring the information on Canadian roasting practices to .date, but also to analyse the mechanism of roasting. Hence, it is proposed to start with a study of physico-cl1emical factors fundamental in roasting, the knowledge of which, by creating a sound basis for a proper roaster design, makes good roasting possible.Physico-Chemical FactorsRoasting can be defined as heating sulphide ores in presence of air below fusion points of the constituent minerals, at such temperatures as to convert metallic sulphides to oxides. Hence, roasting is a chemical process.The object of roasting is, by changing, chemically, mineral constituents of sulphide ores, to make the economic recovery of the desired •Constituent metal by a subsequent standard treatment possible. For instance, pyritic ores, containing gold in sub-microscopic form which no amount of grinding would release, are roasted in order, by oxidizing the sulphides, to open up their structures to such an extent as to enable cyanide solutions to come into contact with the gold and dissolve it. The production of porous calcine is, therefore, the object of roasting of refractory auriferous sulphide ores or concentrates. Such a porous calcine may be defined as a desirable calcine, and the roasts which produce desirable calcines can in their turn be termed desirable roasts."

Jan 1, 1952

By Jürg Schlumpf

Concrete is one of the decisive construction materials, also for the AlpTransit Gotthard Tunnel. The client has many requirements, and many are the solution possibilities that concrete systems can offer. Cement producers and concrete admixture manufacturers have been challenged to design and test jointly concrete systems for cast and sprayed concrete. The testing operation followed the scenario laid out by the Gotthard AlpTransit Project management?s instructions ?Testing system for concrete mixes.? Various supplier teams have applied for the concrete systems for sections Amsteg/Erstfeld, section Sedrun and/or sections Bodio/Faido and have also followed through with the tests. As was to be expected, the rate of failed mixes matched the level of the requirements. Thanks to this system, it was nevertheless possible to test complete concrete systems for all sections and to get them approved. The joint ventures tendering for the contracts were allowed to include only approved mix designs in their bids. Workability and durability are of paramount importance for cast and sprayed concrete mixes. Durability is influenced by the chosen mix design where binder concept and well-defined water content, i.e., impermeability, are determinant. Aggregates for AlpTransit are to be considered as given. The concrete mix design also determines workability. Because ambient conditions and also requirements with respect to workability are subjected to change, it is necessary that the mix designs include control measures. The choice and number of components for the concrete systems (cement, additives and admixtures) allow adaptation to changing conditions. For AlpTransit such adaptive measures must meet very strict requirements.

Jan 1, 2008

By Z. M. Zhang

Fracture grouting is a particular technique which can be used in soils and rocks with low permeability to increase groutability and penetration rates and to solve some special foundation problems by inducing limited and controlled zones of hydrofracture surrounding the injection source. The present paper describes the basic principles of hydrofracture and its application to grouting in deep foundations, and indicates some recognitions about the mechanisms and effects of fracture grouting.

Jan 1, 2010

By Alfred Opengart

During any rush hour, tens of thousands of automobiles clog the main highways leading into or out of our large cities. Inevitably one or more cars stall or plow into another, causing a momentous traffic jam. Traffic backs up for miles as drivers try to maneuver around the roadblock. As commuters, we grin and bear the inconvenience, rationalizing the delay as part of the price one pays to live in a modern society. The truth of the matter is that the engineers planning the roads have the know-how to build adequate bypass alternatives into their design. The problem is one of economics -- can the cost of eliminating roadblocks be justified? Engineers designing solutions to complex materials handling problems for modem distribution centers are just now beginning to ask this question in relation to their work. Unfortunately in many instances, it has taken an expensive "traffic jam" to bring this question to the front. In these cases, a seemingly practical system promising an attractive return on investment -- using the latest equipment and computer controls -- was designed and installed. Everything went according to plan until one day a breakdown occurred. .Product flow stopped, and management realized it was at the mercy of the "machine." In such situations, management had assumed it could minimize the risks of the breakdown by injecting extra manpower to operate the system manually and pay the associated costs. What it had not recognized is that manual intervention is nearly impossible with sophisticated systems. Thus, too often -- and sometimes too late -- management found itself footing a very high bill for losses incurred because of major production stoppages and missed customer shipments.

Jan 1, 1973

By K. Stankiewicz

Projects as regards state-of-the-art mechatronic systems aiming at increase of safety in the mining industry and at improvement of coal production technologies, which have been completed at the KOMAG Institute of Mining Technology, are presented. These projects cover automation, monitoring and visualization systems, systems for implementation of artificial intelligence techniques, and database recording systems. iRIS system for electronic marking, identification, and recording of components of powered roof supports, which was implemented in 31 Polish mining enterprises, is presented as an example of the work directly associated with an increase of operational safety. Specialists from KOMAG, ELSTA, Ltd., and Silesian University of Technology in Poland, have developed flexible, configurable, and scalable system for data management, which refers to all fixed assets of mining enterprises, meeting the requirements of users as regards marking and identification of fixed assets. The system for control of roadheaders using intelligent algorithms, based on artificial intelligence techniques is also the example of innovative actions. This system aims at increasing the safety and effectiveness of teamwork due to a possibility of remote, semiautonomous operation. Introduction of artificial intelligence technology enables adaptation of roadheader mining system to the present mining-and-geological conditions. Moreover, work aiming at implementation of state-of-the-art system for control of mine jig?s beneficiation node, integrating machines and equipment in one system, is carried out as regards automation, information integration, and visualization in coal beneficiation process. Work on recovery and conversion of thermal energy, which is a by-product during operation of machines and equipment, especially mine diesel drives, is presented. Systems for energy recuperation are more and more important due to the necessity of continuous increase of power production efficiency.

Aug 1, 2013

By R. T. Jones

Slags have been produced as by-products from pyrometallurgical processes for thousands of years, and have generally been regarded as waste. Many of these slags are no longer seen as residues merely to be discarded, but as potential economic sources of metals, or as useful by-products in their own right. Slag cleaning can enhance the recovery of valuable metals in existing pyrometallurgical processes, or can produce economic value from recycling old slag dumps. For example, a process has been developed and implemented industrially for recovering cobalt from copper smelting slag in a DC arc furnace. The relatively non-leachable behaviour of glassy slags allows them to be used as a very safe means of disposal of metallurgical waste streams, including many that are classified as hazardous. The high temperatures, reducing conditions, and good mixing that can be achieved in a DC arc furnace enable the effective functioning of this environmentally beneficial means of disposal. Lead blast furnace slag can be rendered safe for disposal by treating it using the Enviroplas process, which strips most of the hazardous lead from the slag (and traps the rest in an insoluble glassy slag) and recovers economic quantities of zinc by absorbing (in a lead splash condenser)the zinc vapour that is fumed off in the furnace. Another example can be seen in the recovery of a chromium- and nickel-containing alloy from stainless steel plant dust, while producing a disposable residual slag. The examples presented here illustrate that it is possible to develop processes that are both economic and environmentally beneficial. Keywords: DC arc furnace, plasma, slag cleaning, cobalt recovery, zinc fuming, Enviroplas, jigging, re-melting fines, environmental, economic

Jan 1, 2004

By Charles B. Carpenter

When a drilling well strikes a horizon in which there is a large volume of petroleum or natural gas under high pressure, danger of a blowout with disastrous results is imminent unless proper precautionary measures are taken. The history of oil-swell drilling has been marked by many blow-outs and wild wells, some of which-have caught fire and burned for long periods. Such incidents nearly always make headline news, but ordinarily few persons realize that what to them is an interesting newspaper item may entail great financial loss to the operator and frequently loss of life or personal injury to members of the drilling crew and others in the vicinity of the well. The blow-out, wild well, and crater are dreaded specters to every thoughtful person in the oil industry because of danger to life and property, underground damage to surrounding wells, dissipation of reservoir energy, and waste of irreplaceable natural resources that blow to the air or migrate to barren formations. Every operator drilling in high-pressure fields must be on the alert always to forestall any conditions that may lead to a blow-out, and his vigilance must not cease until a well is completed and oil, gas, or both are flowing to storage or market.

Jan 1, 1937

By John P. Weir

The planning of an underground mine for successful extraction of a bedded deposit in sedimentary rocks requires the integrated evaluation of many interdependent problems. The development and coordination of feasible solutions are the responsibility of the mining engineer. One of these problems will be discussed herein; this is the design and .layout of mine workings to secure effective control of the strata above and below the deposit. The objective is the simplest possible repetitive system permitting safe maximum recovery at optimum cost. Mining conditions to be encountered must be predictable. The best mining equipment is ineffective unless strata are controlled. Conversely, a mining layout is only of academic interest, if equipment can not be adapted to work it with adequate provision for ventilation, compliance with mining laws, proper ingress and egress and other practical requirements. Strata control, then, is but one of the mining engineer's problems, and the solutions must be worked out concurrently with solutions to other problems. Dr. Karl F. Fetters in his introductory remarks before the Fourth International Conference on Strata Control and Rock Mechanics at Columbia University said that mining engineering ?has come from the stage of empiricism backed by intuitive reasoning, to where it is based on fundamental scientific and engineering principles?. The standard curriculum in mining engineering now reflects such a change. In common with other branches of engineering education, less and less emphasis is placed on practical skills and more and more on broad scientific education. Science, research and the quest for basic truth are stressed, while descriptive courses and the teaching of specific skills are limited.

Jan 1, 1966

Electrochemical Behaviour of Massive Chaclopyrite Bioleached Electrodes in Presence of Acidithiobacillus ferrooxidans and Acidithiobacillus caldus In this work, the monitoring of bacterial and chemical dissolution of massive chaclopyrite was evaluated using cyclic voltammetry (CV); the mineral surface was examined using scanning electron microscopy (SEM) and the elements were examined by Energy Dispersive X-ray Analysis (EDAX). The electrolyte employed for the electrochemical tests was the medium used to bioleaching the electrodes (3.0 g/L (NH4)2+SO4, 0.5 g/L K2HPO4, 0.5 g/L MgSO4+7H2O and 0.1 g/L Ca(NO3)2).The results showed differences in voltagramms carried out by Acidithiobacillus ferrooxidans and Acidithiobacillus caldus: In bioleached electrodes tested in the presence of Acidithiobacillus ferrooxidans, the anodic and cathodic current signals were larger than with Acidithiobacillus caldus. The analysis of CV results allowed attributing the different peaks observed in both the direct and reverse potential scanning to the oxidation of chaclopyrite to a secondary copper mineral (bornite, chalcocite and covellite) and its reduction via different non stoichiometric copper sulphides intermediaries. Surface evidences were observed by SEM, and chemical elements evidences were also investigated by EDAX.

Sep 13, 2010

By Ogden Malin

IN conducting the manufacture of extruded brass rods and brass forgings it has been noticed that there is considerable variation in the physical properties, particularly the machinability of different rods and forgings, even though the composition, working temperatures and method of manufacture remain the same. It is the purpose of this paper to attempt to establish the cause and extent of this variation, and also to determine whether variations in composition within certain defined limits influence hardness and machinability to any marked degree. The writer believes that this variation probably is due to the variation in grain size of the metal, therefore the microstructure of several compositions under various conditions of working were examined in an effort to establish this as a fact.

Jan 1, 1932

By C. Bachmann, M. J. Laurila, A. J. Widenman, A. Klein

Elemental analysis of slurry streams using X-ray fluorescence (XRF) has long been employed. However, detector technology has limited the application of XRF devices. Using detector technology employed on NASA's Mars Pathfinder to analyze soil samples, Process Control, Inc. has developed an on-line analyzer to mount on a sampling system. The prototype XRF elemental analyzer was installed at Detroit Edison's Monroe Power Plant in January, 1998 and has been employed to monitor feedstock quality. A slurry system has been developed for flotation control. This paper describes the testing of the analyzer using the new, draft ISO standard for evaluating the performance of online analyzers (ISO/DIS15239).

Jan 1, 1999

By M S. Reston

The Tonkolili banded iron formations (BIF), Sierra Leone, host extensive iron ore deposits which are of economic signifi cance to the seaborne iron ore trade. The deposits are dominated by a strategic JORC compliant mineral resource of 11.6 Bt grading 30.1 per cent Fe comprised of primary magnetite mineralisation in the form of a fresh metamorphosed BIF featuring a uniform mineral assemblage of quartz-magnetite ± ferro-silicate minerals. Pilot plant metallurgical test work has demonstrated that the production of a magnetite concentrate is achievable using the established beneficiation techniques of magnetic separation and flotation. The concentrates arehigh-grade, and suitable for blast furnace or direct reduced iron pellet feed. The major challenge facing the development of such magnetite deposits at industry competitive production rates is the significant capital investment required for process plant and associated infrastructure.Two well-developed weathering zones exist within the deposits, and are associated with the progressive development of a tropical weathering profile overprinting the primary BIF. These zones feature a near surface hard indurated duricrust up to 60 m thick, and a soft progressively developed saprolite between duricrust and fresh BIF. These zones have been found to be amenable to producing iron ore products including DSO lump and sinter fines from the duricrust, and concentrate from the saprolite. Mineral resources sufficient to support commercial production of such iron ore products were defined by an intensive exploration program in 2010.African Minerals Limited has developed a three phase production strategy to progressively self fund the development of the Tonkolili strategic magnetite project by:• commencing a Phase I 12 Mt/a DSO operation in Quarter 4 2011,• increasing production in Phase II to 35 Mt/a with the commissioning of a saprolite beneficitation plant and associated infrastructure upgrades, and• developing a 45 Mt/a Phase III operation producing high-grade magnetite concentrate.The comparatively low capital and operating costs of a duricrust DSO lump and sinter fines operation coupled with its proximity to ground surface make it highly attractive for the generation of early cash flow for the Tonkolili project. Revenue from this early production may be used to selffund the subsequent development of phases requiring progressively more significant beneficiation plant and infrastructure.

Jul 11, 2011