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By B. S. Terry, C. L. Harris

Reduction kinetics from slags containing CuO(0.5), ZnO, PbO, NiO and SnO into a Cu-based metal phase were subjected to computer simulation using a previously developed model for the kinetics of metal-slag-gas reactions that assumes mass-transfer control in all phases. The effects were examined of changing bulk Fe oxide activity, gas reducing potential, temperature, Fe content of the Cu phase and metal/slag ratio. The results permit practical conclusions to be drawn about industrial slag-cleaning practice, but the model is still limited in terms of thermodynamic inputs and the idealisation of reaction conditions

Aug 1, 1995

By Cem Şensöğüt, Özer Ören, Yaşar Kasap

The mining sector, which has an important place in terms of raw material and energy supply, is referred as a sector with one of the highest fatal accidents in comparison with other sectors. In this century, where occupational health and safety awareness has increased, it is important to review the past accident statistics and to determine the current deficiencies by using the information in the inventory. In this study, the Malmquist total factor productivity index (MPI) has been utilized to investigate the changes in the work accidents occurring in the Western Lignite Corporation (Turkey), where underground and surface production methods are applied, and to determine the measures to be taken. According to the results obtained, both the decrease in production amount and the increase in the number of accidents caused inefficiencies during the period in concern due to the expected 10-year economic life of the mechanized system operating in the underground production panel that came to an end in 2007 and the flooding took place in early 2017. Compared with the underground operations, it has been determined that production can be carried out at the appropriate scale despite the heavy working conditions encountered due to the changing climatic conditions and the progress of production in the surface operations.

By E Hawkins, S Sheldon

Block caving is becoming a more widely adopted mining method allowing for underground massive low grade orebodies to be extracted economically. Underbreak during cave propagation is difficult to predict in terms of recovery and is not well-researched due to the small number of caving operations. During mining of E26 Lift 2 (E26L2) block cave at CMOC Northparkes Mines, a wedge of high grade material failed to cave, even with the assistance of preconditioning and subsequent attempts to induce caving. The ultimate solution for recovery of the uncaved wedge was the establishment of the E26 sublevel cave (SLC), which commenced mining in 2015, with production following in 2016. The SLC provides approximately 1Mtpa to supplement the lowering grade of the current E48 block cave feed. Applying the sublevel caving methodology to recover block cave underbreak has proven challenging. The impact of the caving stresses and preconditioning of the wedge have caused production limitations requiring continual remediation throughout production of the E26 SLC. The dependence on remediation work created a roadblock to implementing precharging as the prevalence of brow loss raised concerns over the inability to hook up the charged ring. In 2018, a wireless initiation trial was completed in the E26 SLC over 24 rings. The trial showed that precharging was achievable in this environment and greatly improved the safety of charge up personnel.

Mar 15, 2021

By R. Stefanko

This first Annual Report covers the work on Contract No. H0377043 "Cable for Face Equipment", from August 1, 1977 to July 31, 1978. It reports the progress in the three areas of over-and short-circuit protection, cable ampacity research and cable couplers. Field trips have established many interesting facts related to circuit breaker settings and cable size. For example, the determination of cable sizes depends on the RMS duty cycle current determined by a particular piece of equipment, but the actual selection of the cable to be used is often a function of the maximum allowable circuit breaker instantaneous settings as specified in Title 30. In order to avoid nuisance tripping as a result of instantaneous starting current field, laboratory and analytical studies are being conducted to determine proper settings and cable sizes Also an extensive program has been established to monitor the performance of high voltage cable couplers and determine their modes of failure. Various equipments are being designed for laboratory testing, and an extensive reeled cable experiment is also under way.

Jan 1, 1978

By John M. Popovich

Disposing of coal mine waste at the surface has been and continues to be a problem which has yet to be resolved within the coal mining industry. A possible solution to this problem is to return the refuse back into the operating underground mine generating the waste material. It is believed that the approach described will provide an inexpensive and pratical solution to the problem. The designed system is installed and operable at the Millers Cove Energy Company, Inc. property in Lee County, Virginia. This system limits surfact facilities to a minimum size. It incorporates state-of-the-art hydraulic transport and backfilling technology and equipment to systematically backfill areas within the active mine. It maximized the benefits of reducing treatment of coal wasts while it minimizes environmental impacts on groundwater. The system approaches the problem in a manner to maximize benefits and minimize risks. The cost of returning coal waste back underground at the Millers Cove site is estimated at $0.67 per ton of marketable coal (1982 dollars), which is slightly higher than their surface disposal cost of $0.61 per ton of marketable mat (1982 dollars). The underground disposal costs do not include cost savings that should be realized within the preparation plant and treatment facilities at the surface. Preliminary tests of the system were conducted at the surface; funding restrictions prevented an in-mine trial. Efforts should continue to demonstrate the feasibility of solving the problem of refuse disposal. The installed system and plant at Millers Cove should provide the opportunity to test an underground disposal operation. This report contains guidelines to pursue this opportunity.

Jan 1, 1986

By N. Dhawan

With ever-increasing demand, low-grade complex ores and strict environmental regulations, metallurgical processing options have become limited. Heap leach technology provides several benefits to combat these issues including low cost, flexibility and diversified process conditions. This paper provides an overview of heap leaching technology with specific emphasis on chemical aspects. Hence, influencing factors, advantages and disadvantages, testing approaches and some fundamentals will be discussed. Finally, heap leach technology for different ore types (copper, nickel, uranium and gold) will be briefly compared.

Jan 1, 2012

By C. E. Wood

[Because of the renewed i~,ortanc of the strate ic netal ~ngane8e the Bureau of Mines is conductin further ro~aarch on pyrometallurgica1 ~ethods of boneficiating 0 ngani.foro'l iron ores nnn lo\,f-~~r de oanganesc ores. Published data on .the l2~roI'let llurgica.l treatnent of tl::1.nganse8 ores have been revi .. \-'en by Jose-ph ? .2]

Jan 1, 1940

By C. E. Wood

Because of the renewed importance of the strategic metal manganese the Bureau of Mines in conducting further research on pyrometallurgical methods of beneficiating manganiferous iron ores and low-grade manganese ores. Published data on the Pyrometallurgical of manganese ores have been reviewed by Joseph.5/ A method of treatment that has received less consideration than others is the matte smelting of manganese or the separation of manganese from the iron and the gangue in an ore b, formation of a matte, that consists principally of esulfide of manganese. A procedure of this type has been patented by Betts.6/ Lofquist7/ claims advantages for the production of a sulfide-oxide matte as a method of recovering manganese in alloys containing manganese and iron.

Jan 1, 1940

By T. Stauffer, B. McGunegle, A. Adu-Acheampong

The Fairmount Minerals, Inc., Maiden Rock underground sand mine historically delivered air to ventilate diesel-powered equipment at its working faces through high-resistance, 15-inch-diameter PVC distribution lines. In support of plans for expanded production, three new, low-resistance ventilation design alternatives were analyzed. The study determined that adequate ventilation for expanded production was possible with various commercially-available, high-volume/low-pressure fans combined with a systematic layout of control structures. The recommended re-design was implemented in 2001, resulting in a significant increase in flow volumes and a noticeable improvement in the mine environment.

Jan 1, 2007

By R. Venugopal, Saxena. V. K., U. Sankrityayan

"There is a dire need of a technology which can break the mineral interfaces to enhance liberation with minimum energy consumption in mineral beneficiation processes. Understanding of mineral crystal system and interfaces is essential to develop such methodology. So, this study is carried out to find out the role of mineral crystallography in milling and liberation. Data related of mineral crystallography, Vickers Hardness Number, Bond Work Index and beneficiation processes were collected from literature and detailed statistical analysis has been carried out to establish a correlation among these parameters. It was found that atomic weight and cell parameters shown statistically significant relationship with Vickers Hardness Number of minerals, which controls the milling characteristics of ores. Liberation characteristics of five different kinds of ores were analyzed considering the types of interfaces between valuable and gangue minerals. It was found that phase interfaces play vita role in liberation and coarser liberation can be achieved in the minerals of incoherent crystal systems like manganese and zinc ores. Study of this subject can help us to understand the effect of stress wave propagation in solids and its effect on crystal interfaces. It can also help us to design a technology of future to break the mineral interfaces.INTRODUCTIONCommunition is energy intensive mineral processing operation and consumes up to 2% of the total electric power generated in the world. Energy consumption due to comminution is increasing every year as there is growing needs to exploit lower grade ore bodies and process rejects (Blazy et al., 1994; DOE, 2005). Low grade ores require crushing and grinding to liberate the valuable minerals which are further separated from gangues by various beneficiation methods like gravity separation, floatation, leaching etc. Currently, comminution methods are selected based on the reduction ratio and energy consumption but effect of grinding methods on subsequent processing methods specially on liberation also need to be studied to optimize the entire beneficiation process. Most of the attempts made in past to minimize the energy consumption in milling to enhance the mineral liberation were focused on compression mechanism, chemical additives, thermal treatment, microwave treatment and electric disintegration (Kilpelm and Austin, 1982; Norgate and Weller et al, 1994; Bearman et al., 1997; Kumar et al., 2010; Wang el al., 2011; Singh et al., 2012). But the role of mineral crystallography on milling and liberation behavior of minerals not fully explored yet."

Jan 1, 2013

The following report summarizes the results of engineering feasibility studies whose purpose was to assess the probable efficiency, reliability, safety and cost of a number of possible methods for removal of radon gas from the ambient air in underground mines. Fourteen candidate techniques were evaluated. Seven of these were based on specific individual principles, and seven were based on combinations of these principles. The individual principles were as follows: 1. Activated charcoal 2. Organic fluids 3. Semipermeable membranes 4. Molecular sieves 4. Cryogenics 6. Chemical reaction 7. Centrifuge The combinations were: 8. Cryogenics and activated charcoal 9. Cryogenics and molecular sieves 10. Cryogenics and chemical reactions 11. Membrane filters and organic fluids 12. Membrane filters, cryogenics and activated charcoal 13. Membrane filters and chemical reactions 14. Silica and an Organic Fluid

Jan 1, 1975

By Klaus Pöllath

The Netherlands RandstadRail project makes use of a large range of sophisticated geotechnical techniques to allow a shield driven tunnel to approach the central station of Rotterdam. This paper describes the construction of three deep excavation pits constructed with 1.2 m and 1.5 m thick diaphragm walls. Besides the presentation of the actual diaphragm wall activities special consideration is given to the break-in and break-out situations of the TBM into the deep excavations pits using sealing blocks and partly glass fibre reinforcement in the diaphragm walls.

Jan 1, 2006

By Daniel L. Hanson

This paper presents a case history of the design, installation and performance of a tied-back tangent caisson retaining wall which was constructed as part of the Third Harbor Tunnel project currently underway in Boston, Massachusetts. The Third Harbor Tunnel project consists of a large multi-lane transportation tunnel which is being constructed by the sunken tube method. In this type of construction, the tunnel alignment, slopes and bedding are excavated and installed underwater and the tunnel sections floated over the proper alignment and sunk in place. The tangent caisson retaining wall discussed in this paper was constructed to provide support of the upper portions of the tunnel excavation at the East Boston Portal where the tunnel exited from below the harbor and continued underground on shore. A portion of the tangent caisson retaining wall was also utilized to provide earth support for the barge unloading facility where spoil from the tunnel excavation was transferred to surface vehicles for removal from the site. PROJECT BACKGROUND The tangent caisson retaining wall was constructed by The Millgard Corporation (TMC) as a subcontractor to the Boston Third Harbor Tunnel Contractors, a Joint Venture which consisted of the firms of Morrison-Knudsen Corporation, Interbeton Inc., and J.F. White Contracting Company. The entire project team is listed below on Table 1. The design of the tangent caisson wall system was performed by Hanson Engineering, P.C. (HE) acting as design consultant to TMC. The retaining wall system incorporated a single row of pressure injected earth anchors (tie-backs) as part of the design. The earth anchors were designed and installed by Drill Tech as a subcontractor to TMC.

Jan 1, 1994

By M. H. Solomon

After the global financial crisis of 2008, African mining is entering anew phase of development. The rapid withdrawal of emerging market funding from the critical exploration and development industries provided a hiatus in funding, a gap which was quickly filled by Chinese and other Asian investors. While the continent is still economically dependent on its extractive industries, the prevalence of Dutch Disease has undermined Africa?s ability to benefit fully from its mining, oil, and gas industries. While the extractive industries are closely related to many of the more fragile and failed states in Africa, it is equally true that the strongest states in Africa have mining-based economies. This paper explores the possible linkages between mining, strong and weak political economies, and poverty in Africa. It draws the conclusion that neither Dutch Disease nor Resource Course is a given in resource-endowed countries, and that it can be avoided if the mining economies in these countries are actively integrated into their respective broader economies and used to foster economic diversification. The author asserts that given the capacity constraints of many African governments, it is contingent on mining companies to become integrally involved in catalysing diversification around their infrastructure and supply chains.

Jan 1, 2011

By Steven D. Knudsen, Dale S. Preece

Computer modeling of the blasting process can aid in gaining an understanding of the physics controlling the process. The sequence of events in a blast occur so rapidly and in such a violent environment that measurements are still difficult to obtain. Computer modeling using a program such as DMC [Taylor and Preece, 1989a, 1989b] can provide insights into the physics of the rapid and violent events associated with a blast. DMC has been used to simulate crater blasting @‘teece, 199Oc] and the blasting of Oil Shale for modified in-situ retorting [Freece, 1990a, 1990b]. This paper will address the influence that damping has on the velocity distribution in the rock mass during the rock motion phase of a blast. Since velocity distribution is a controlling factor of muck pile shape, damping also conbibutes to muck pile shape.

Jan 1, 1992

By Fernando Cillóniz

Benchmarking es un proceso de comparación y medición de los procesos de negocio de una organización, con aquellos que lideran el mercado. De forma que se obtiene información para mejorar el desempeño de las empresas. En ese sentido, el presente texto señala la utlidad del Benchmarking en las empresas donde el uso de la Internet y las tecnologías de la información permiten hacer más eficiente las comparaciones e intercambio de experiencias y conocimientos, así como internacionalizar el proceso.

Aug 25, 2002

By Peter Townsend, Sergei Diachenko, Allan Moss

The Palabora Mining Company has successfully extended the life of its operation by developing a 30,000tpd block cave underground mine below the now closed open pit. The process of transitioning from surface to underground mining has been technically, operationally and managerially challenging. This has been due to a number of factors; in particular, the development of a block cave in a very competent rock mass. The competence of the rock mass is clearly demonstrated in the open pit that preceded the block cave, one of the steepest deep open pit excavations in the world. With cave breakthrough, however, the pit was ?instantaneously? deepened by 400m causing a major failure of the northwest wall involving close to 100Mt of waste material.

Jan 1, 2006

By R. L. Loofbourow

R. L. LOOFBOUROW 26.1-WATER FLOW, USE, EFFECTS, CONTROL Sec. 4 discusses ground water as a mineral resource. This section deals wits its control. 26.1.1-IMPORTANCE Flows of water have an important effect on the cost and progress of many deep excavations. The existence of water limits the methods which can be used in some and presents hazards in others. Lowering the water table may reduce the flow of springs and wells, with legal liability. Some mine water is used directly, some must he treated before discharge, and some contains dissolved solids which can be recovered profitably. Loss of life, property and production from flooding is grim, yet scores of mines have worked safely for generations under ground-water reservoirs, lakes and even the sea. The need for better control of mine water is measured by the severity of recent floodings, concern with the quality of the effluent, and direct and indirect costs of working wet ground. There are improvements in freezing in shaft sinking. pumps and their controls, treatment of mine water before it is pumped, bulkhead construction and certain efforts to reduce inflow. 26.1.2-PUMPING COST VS. COST OF WET WORK Direct operating and capital costs of pumping are more evident than indirect items, such as provision of extra standby power and maintenance facilities, The total of all these items is the cost of pumping water from an excavation. This is only a part of the extra cost of working wet as compared to dry ground. Less productive methods, less efficient equipment and more expensive explosives may have to he used in wet work. Wet rock plugs certain equipment. Maintenance is higher and labor less efficient. The cost of any means of keeping work drier should he weighed against the higher cost of working wet. The true difference in the cost of working wet ground, compared with dry, probably is known at only a few places (see checklist of cost items. Sec. 26.4.13). An extreme comparison of mining wet and dry ore is available from Ambrosia Lake, N.M. (Fig. 26-1). Between 1963 and 1967, a wet and a dry mine were worked by the same company under conditions otherwise comparable. Average operating cost at the wet mine, pumping 1,600 to 1,800 gpm. was $16.06 per ton of ore. The comparable figure for the dry mine was $7.50. Principal differences included the fact that the wet mine was worked from drainage levels below the, ore with rail haulage, the dry mine in the ore with off-track equipment loading and hauling to the shaft. In the wet mine, ore packed in chutes, cars and skips and froze in surface bins, stockpiles and trucks. Wet-mine costs included drilling drain holes, building and maintaining ditches and pumping water containing abrasive solids.

Jan 1, 1973

By Chuck Edwards

"Milling operations in northern Saskatchewan’s Athabasca Basin have produced uranium continuously since 1975. Over that period, the Athabasca Basin has been one of the world’s premier uranium camps, yielding more than 660 million lb of U3O8. In this paper, the author describes former and current milling operations and discusses why and how the milling process has changed and developed over the past 35 years. The author’s considerations for the future of uranium extraction in the Athabasca Basin close out the paper.INTRODUCTIONThe roughly oval Athabasca Basin in northern Saskatchewan occupies nearly one third of the surface area of the Saskatchewan Shield. Its sandstone-like deposits lie unconformably on the older basement. The basin hosts many high-grade unconformity-type uranium deposits(Saskatchewan Energy and Resources, 2010) for which the Athabasca Basin is world famous. Uranium production in the Athabasca Basin has come from four mills. In the order of startup these are Rabbit Lake, Cluff Lake, Key Lake and McClean Lake. General data (AREVA, 2010; Cameco, 2010; Denison 2010) for each mill are shown in Table 1."

Jan 1, 2011

By H. R. Banks

IF you have ever travelled in the valley lying between the Selkirks and the Rockies in the East Koorenay district, you will have noted that the former mountains are rounded and massive, while the serrated peaks of the latter, fingering into the sky, bring an entirely different. picture. These two mountain ranges, with the comparatively level valley between, serve splendidly to introduce the subject for discussion. It is rather strange that, despite the fact that wear is undoubredly the greatest force with which human ingenuity bas to contend, it has come in for very little study from the stand point of pure science. Empiricism has been the sole ally in the fight for improvement! That we may have a clear understanding as to what we mean by wear, I would include in the term the breaking dawn of ail solid matter, from the natural wearing dawn of the mountains previously mentioned, to the hale in the mill pipe-line, which forces one to shut-down-usually at some un-earthly hour-to carry out a repair. It seems a far cry from mountains to mill launders or pipe-lines, but, magnified sufficiently, most of the materials with which we have to deal would show surfaces not unlike those we see around us. The progressive steps of wear, or ?erosion' as our geological friends would prefer to term it, are exemplified in the two ranges of mountains and the valley between. True, the wearing dawn by natural forces is a slow process. The aeons which have passed since first these mountains were formed seem endless. The natural forces pitted against them seem puny in the light of the interminable rime that has been needed to effect the changes. But here, as in the case of the materials with which we are dealing day by day, the combination of many forces ultimately brings about that condition which we describe as 'worn out'. In the case of the mountains, it is when they are finally levelled into plains, and in the case of equipment which we use, it is when that equipment will no longer serve its purpose.

Jan 1, 1943