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As 1979 drew to a close, it was obvious that China would have another good year with output of most industrial products at 3-9% above levels attained in 1978. Most increases were registered on the basis of maximum utilization of existing capacities and nationalization of procedures and methods. There were also distinct improvements in the quality and variety of products. Coal output probably surpassed the 650-Mt level in 1979. Steel output was expected to reach the 35-Mt level, an increase of nearly 10% over 1978. Based on the vast amount of housing and road and project construction, cement production more than likely surpassed 70 Mt. The nonferrous base metal industries improved somewhat in 1978, but actual output levels in recent years may have been a little higher than previously estimated by the outside world. Stagnate world demand slowed growth in the "export metals" sector. Minerals like magnesite and talc were produced at tonnages much larger than previously thought, with gold also falling into this category. Sulfur and pyrite production are still short, although a big pyrite mine was being brought into production. Barite out-put was reportedly up and fluorspar output held its own. Westerners generally concede that difficulties in transportation and power supply are holding back mineral production. Throughout 1979, basic construction continued on the majority of projects started by the Chinese and those few foreign projects contracted before the adjustment of industrial priorities. Foreign Ventures Perspective The foreign connection looms large in China's plan for modernization. In effect, it is an extension of what China wants to do in terms of "walking on two legs"-that is, develop what can be done locally to the fullest extent, then rely on international technology to move into the bigger and more complicated projects. Foreign projects are designed to complement domestic projects rather than replace them. Many foreign projects were started or continued by the Chinese in 1979. Building the necessary infrastructure for the projects is usually a Chinese endeavor and requires Chinese technicians and money. In areas with a strong economic base, this activity proceeds without foreign aid. In other areas, added funds are requested. Foreign funds can come in many forms-equipment technology, low interest loans, equity capital, advance-of-funds on the basis of future delivery in kind, and joint venture money. The Chinese are exploring all these avenues, with the strategy of minimizing foreign exchange needs for individual projects. They feel very uncomfortable with high interest rates, even though interest can be treated as operating ex¬pense rather than capital expense. Then there's the question of rights. Will Chinese sovereignty be affected? Can foreigners own land, in addition

Jan 3, 1980

By Larry M. Southwick

Steel mill electric arc furnace dust is a RCRA listed hazardous waste and its treatment and/or disposal are regulated by a complex set of rules. These regulations were originally established to encourage recovery and recycling of valuable components. For EAF dust, the more valuable constituents include zinc, lead, cadmium and iron. In fact, current trends are in the opposite direction, as the regulations have complicated the ability to commercialize new treatment technologies and created substantial roadblocks and liabilities for processors. As a result, almost half of the EAF dust generated in 1997 will be landfilled. The problems are compounded by difficult processing requirements, less than sterling examples of technology development and mechanical and operating problems. This paper explores some options to simplify the processing requirements and thereby easing difficulties in commercializing new technologies and expediting the recycling of recovered metals. Dust processing usually includes a simple step followed by two complicated steps. The simple step is fuming of heavy metals away from iron and other residues. The complex steps are (1) separating and purifying the heavy metals and (2) upgrading the iron residue. The first complex step can be simplified by producing an intermediate product that is amenable to processing by zinc refiners. This route benefits from the currently underutilized (by dust processors) resource offered by refiners, who have experience in and existing processes for separation and purification of zinc-based heavy metals. Various processes and their associated product options are reviewed and compared. Future directions for dust processing developments are suggested.

Jan 1, 1998

By Richard C. Corson

The new 9300 TPD sinter plant being built for China Steel Corporation is incorporating the latest computer technology for plant control systems. The control system will use a central computer and distributed micro-processors to control instrument loops and switching logic in the blending yard and sintering plant. All plant functions, including combustion and fan controls, will be controlled by remote microprocessors located throughout the plant, and connected by a communications link to the centrally located computer and control room. The design, programming, construction and operation of a microprocessor based control system presents new challenges to the control engineer. With microprocessors in the control system, more power exists in the individual control loop and many supervisory functions may be added at the loop level. The specification of the microprocessor system and the resolution of hardware design and control system design can lead to development of powerful systems capable of higher level control and optimization functions

Jan 1, 1981

By C Muñoz, N Ortega, J Vergara, D Avilés

Mass blasts have been the subject of extensive studies because of their potential benefits in mining operations. However, it has not been possible to advance due to the paradigm that states that the blasts near the designed final wall or to critical structures have to be low tonnage. Another reason is the absence of specialised simulation programs to more precisely determine the influence of the energy released by blasting to the rock mass. There are some studies that demonstrate the possibility of massive blasting that maintain the design of the final slope (Farias and Santander, 2014). It should be noted that these studies develop the concept that the size of the blast should not increase the peak vibration in the rock mass.The study was carried out in partnership with Los Colorados Mining Company. Analysis, reconciliation and wall control for two types of blasts were performed:blasting production: approximately 850 000 t, with special wall control considerationsblasting of approximately 950 000 t over the entire width of the bench.Monitoring systems were used in the near field and far field using examination of holes in order to obtain information to assess the impact on the rock mass and then to compare these to conventional blasting combining production and contour blasting.The results show that for a large blasted volume, production and/or those generated from toe to crest on the bench did not produce more impact in the rock mass than the conventional blasting.The conclusions drawn from this study are:an improvement in the excavation rate of 7500 t/h that is higher than the maximum rates normally obtainedthe peak vibrations of the P wave generated by both blasts did not exceed the peak particle velocity criteria (Vergara and Muñoz, 2014)holes examination indicating no difference in their entire length, in pre- and post-blast reviewover US$2 000 000 savings generated in the year (estimated by the client) (Avilés, 2014).CITATION:Vergara, J, Muñoz, C, Ortega, N and Avilés, D, 2015. Benefits related to applications of a mass blast in open cut mining, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 625–632 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By R. L. Crosby

The Bureau of Mines investigated alloys of copper with 2, 3, and 4 vol pct alumina and with 2 vol pct yttria. Alloys were prepared by a coprecipitation process and were fabricated by pressing and sintering of powders, extrusion, and swaging. Tensile properties at room and elevated temperatures, stress-rupture strength, electrical conductivity, and density were measured. The superiority in elevated temperature strength of dispersion-strengthened copper to OFHC copper was confirmed. Increasing the oxide content from 2 to 4 vol pct produced only a small improvement in strength properties and decreased the electrical conductivity. The 3 vol pet alumina alloy had the best overall combination of properties.

Jan 1, 1969

By John M. Lovejoy

NATURAL resources become a source of wealth as they are exploited and made available to the people in usable form. Experience has taught us that Nature does not readily give up her treasures, but the ingenuity of man in the field of techologic progress is required to find and efficiently exploit these resources. History has also demonstrated that with advancing technologic knowledge the. world has become progressively richer in its resources. Those that could not be commercially exploited are now being turned to beneficial use. Through expanding technology and the use of substitutes and synthetics, availability of the world's sources of natural wealth is today many times that of a hundred or a thousand years ago. And so it is with petroleum. Technology is also the great multiplier of our petroleum resources. Through improvements in the art of finding, drilling, and producing, our ability to meet rapidly increasing demands over the last quarter century has been maintained. On the other hand, had our

Jan 1, 1944

By R. Q. Honaker

A significant problem in ultrafine particle classification is the significant amount of submicron particle by-pass to the coarse particle stream. In classifying cyclones, submicron particle by-pass to the underflow stream can be reduced by decreasing water recovery. Past studies have shown that a reduction can be realized when the feed solids concentration is increased or the apex diameter is reduced. However, both adjustments tend to increase the particle size cut point and negatively affect classification efficiency due to the impact on slurry rheology. The addition of a viscosity modifier to the feed stream of a classifying cyclone improved the classification performance and decreased the particle size cut point over a range of feed solids concentrations. The detailed test program investigated the use of the modifier in conjunction with varying apex diameters to identify conditions that minimize ultrafine by-pass. With small apex sizes, roping conditions were readily eliminated by the addition of viscosity modifiers. The addition of the modifier had no deleterious effect on froth flotation performance, which commonly serves as a downstream separation process. The fundamental and practical benefits of viscosity modifiers in classification processes are discussed in this publication.

Jan 1, 2006

By O. Mejia, J. Drozdiak

"This paper summarizes a comprehensive energy and cost study comparing an existing SAG mill based circuit at Huckleberry Mine with two proposed circuits involving comminution technologies which are associated with energy efficiency: high pressure grinding rolls (HPGR) and high speed stirred mills. The specific energy requirements expressed as kWh/t for the proposed circuits were determined from pilotscale HPGR and stirred mill testing conducted at the University of British Columbia. Samples and operating data were collected from Huckleberry’s copper-molybdenum concentrator to evaluate current mill performance for comparison. To support the base case, the SABC circuit was modeled using JK SimMet® software. The main comparison focused on the complete energy requirements for each circuit, including materials handling equipment such as conveyors, screens, feeders and pumps. This paper also provides capital and operating cost estimates for each of the comminution circuits. The results showed that the HPGR - ball mill circuit achieved a 21% reduction in energy consumption over the existing SAG - ball mill circuit at the same P80 grind size of 160 µm. At a grind of 80% passing 75 µm, the HPGR - stirred mill circuit showed a 34% reduction in energy compared to the base case. It was concluded that the energy reduction for the new flowsheets significantly improved the economics of the Huckleberry comminution duty.INTRODUCTIONUp until now, tumbling mills such as AG/SAG mills and ball mills have had a dominant bearing on the design and economics of comminution circuits. However, it is commonly agreed that the majority of employed comminution processes are energy intensive and energy inefficient, accounting for up to 80% of overall process plant energy consumption and having an efficiency of as low as 1% (Abouzeid and Fuerstenau, 2009; Fuerstenau and Abouzeid, 2002). The U.S. department of energy reported that there is a potential to reduce energy consumption in the metals industry by up to 61% from current practice to bestestimated practical minimum energy consumption; suggestions included the implementation of best practices and the adoption of energy efficient mining and mineral processing technologies such as advanced blasting techniques, high pressure grinding rolls (HPGR) and stirred mills (U.S. DOE, 2007)."

Jan 1, 2013

By H. E. Rojas

The primary objective of most comminution operations is liberation; however, mill performance is generally quantified in terms of particle size. Only recently has the use of image analysis equipment made it possible to quantify mill performance on the basis of liberation. In this investigation, a series of tests were carried out to study the effect of mill operating parameters on the liberation of sphalerite from a sphalerite/dolomite ore. The parameters studied included mill rotational speed, mill loading and ball size. The results of this work appear to indicate that sphalerite liberation is improved under conditions that promote impact breakage, while dolomite breakage is enhanced under attrition conditions.

Jan 1, 1990

By C Fong

Compliance Planning is an active approach to ensure mining operations align more closely to their longer-term plans. Through Compliance Planning, operations can not only measure their performance on intervals as short as intra-shift, but they can then apply corrective measures to ensure they remain as close as possible to the plans. Compliance Planning targets short-term and execution level teams, as these are the shortest duration planning divisions commonly found in mining operations. Compliance Planning combines live information with intelligent planning capabilities to provide a framework that enables mining operations to realise a significant improvement in reconciliation of plan to actual movements.

Jun 22, 2022

By Lidong Teng

ArcSaveTM is a new generation of electromagnetic stirrer (EMS) from ABB for electric arc furnace (EAF) operation. Its goal is to improve the safety, increase the productivity and reduce costs. Electromagnetic stirring in the melt bath during arc furnace operation will affect the scrap smelting, bath temperature distribution, refining reactions, and also the tapping practice. This paper has summarized the investigation results obtained from the first ArcSaveTM system installed in a 90 ton EBT arc furnace in USA. The hot test results show that ArcSaveTM has enhanced the heat and mass transfer in the arc furnace process. This results in a faster scrap melting rate, lower slag superheat during arcing, more homogenous melt bath, higher decarburization rate and higher EBT free opening frequency. ArcSaveTM has also reduced the tapping temperature and tapping oxygen in the steel. This brings a higher scrap yield and saves ferroalloy consumption in the downstream ladle furnace operation. The lower energy consumption, short tap-to-tap time, and consistent furnace operation bring increased productivity and safety.

Aug 16, 2017

By Deirdre Bradshaw, Cornelius Vos

"The detailed understanding of the variability in process performance parameters within an ore body forms a key aspect of ensuring that proper decisions are made with regards to the economic viability of that ore body. To gain this understanding, various tools have been developed over the years, of which the batch flotation test is the most well-known and applied technique for investigating the flotation separation of ores. In this paper, the Julius Kruttschnitt Mineral Separability Indicator (JKMSI) is put forward as a small-scale test, suitable for the characterization of the flotation separability of copper porphyry ores. It is demonstrated that the JKMSI can be a complementary technique to the batch flotation test, with the capability to further improve the knowledge of ore body variability. The response from this test has been shown to be sensitive to particle size and modal mineralogy, providing a critical link between flotation and upstream comminution activities. The trade-off between the fineness of grind and the recovery target can thus be evaluated to determine the minimum energy application required for optimal separation economics. The test is designed to utilize small sample quantities of various sizes, providing an opportunity to increase our understanding of ore variability through increased tests. This complements our ore body knowledge and combining this with efforts in comminution (Powell, 2013) provides a platform for extending the concept of flexible circuit design."

Jan 1, 2014

By Jean-Paul Simoes

The development of the blast furnace over the last years lead to a substantial increase in production capacity and productivity. This development triggered an evolution of the cooling systems in order to cope with the raising heat loads. The excellent protection of the shell by copper staves allowed blast furnace operators to achieve campaign lifetimes of more than 20 years. However in recent years some blast furnaces have experienced severe wear of the copper staves due to abrasion. The influences of the blast furnace design as well as of the operation conditions on this premature wear have been analysed and the mechanisms leading to the wear will be explained. New developments in the copper stave technology are part of the solution for avoiding premature wear during periods with less favourable conditions. The protection mechanisms made available by the new design extend the inherent protection mechanisms of copper staves to these periods. BFXpert® system is the ideal tool for the monitoring of the process data, the process models and the recommendations given by Sachem® support the operator in choosing efficient operation points. The charging with a Bell Less Top® (BLT) allows an accurate controlling of the blast furnace with regard to the optimization of the gas distribution. High performance operation together with long campaign lifetimes are thus made possible.

Aug 1, 2018

By P. Schumacher, M. Fein

"INTRODUCTION Newmont’s Twin Creeks operation, part of its Nevada operations, produces gold from two large open pit mines. Mined ore is processed at one of three on-site facilities: a refractory mill with two autoclaves, an oxide mill and heap leaching facilities. Twin Creeks also processes various off-site sourced concentrates and ore including high grade underground ore from the Turquoise Ridge joint venture with Barrick Gold Corporation. This paper discusses Twin Creeks’ strategic mine planning process which is part of an in-depth continuous improvement program called “Full Potential.” The process involves cost analysis, phase design validations, life-of-mine production scheduling optimization, mill blending strategy and stockpile management. Through this Full Potential strategic planning, Twin Creeks is creating significant value by increasing near term free cash flow and life of mine net present value (“NPV”) and achieving cost reductions. TWIN CREEKS OPERATION Twin Creeks is one of the major gold producers in Newmont’s Nevada operations (see Figure 1, 2 and 3). Located approximately 15 miles north of Golconda, Twin Creeks produced approximately 28 % of the Nevada operation’s 2013 gold production of 1.8 million ounces (Newmont 2014). The production included Turquoise Ridge sourced gold ore from the joint venture (75% Barrick Gold Corporation, 25% Newmont).At Twin Creeks, there are two large open pits, named Mega Pit and Vista Pit (see Figure 4, 5 and 6). There are 3 to 5 phases in Mega Pit and 2 to 5 phases in Vista Pit depending on the gold price assumption. There is also an underground exploration project at the bottom of the Vista Pit. Twin Creeks produces gold from a variety of ore types requiring different processing techniques depending on economic and metallurgical characteristics. To ensure the best use of processing assets, engineering and processing groups at Twin Creeks utilize a Mixed Integer Linear Programming (“MILP”) model to guide the flow of mine sequences and material routing to various process facilities (Kawahata, Schumacher and Hufford 2013)."

Jan 1, 2015

By Lucien Eaton

INCREASED mining activity during the past year has brought to light changes in mining practice and advances in technique, born and incubated in the period of depression from which the mining industry is now emerging. Although the tendency toward large output from individual mines has continued, a salutary trend is evident toward greater efficiency at small mines, in which the gold mines of Canada have led the way. Improvement in excavating machinery and washing plants for small placers has continued, and knowledge of the possibilities and limitations of this kind of equipment has increased. Greater portability through sectionalization has been the keynote. Power, shovels and draglines mounted on caterpillar treads move from one deposit to another under their own power, and floating washing plants mounted on pontoons can be taken down, moved, and set up again by a small crew of men in only a few days.

Jan 1, 1937

By M. Mezzetti, E. Anders, O. Popov, P. Hoske, H. Lieberwirth, M. Voigt

"The material breakage induced by high energy electric discharges is known in general as electric impulse technology. This technology can be used for processing solid materials, such as rocks and ores. The electric impulse technology has been around for about 60 years, originally developed and intensively investigated by Russian researchers. However, the application fields have been limited to research and laboratory scale projects. Currently, there are new attempts to transfer this technology into practical industrial applications. Practical examples include drilling of deep geothermal wells with an electric impulse driven drill-head. Traditional comminution implies high energy consumption, hence, high costs. The Electric Impulse Technology is interesting for comminution of mineral and complex ores since it could allow improved recovery and energy reduction, thus resulting in significant savings. Another advantage is the dust free processing, which contributes to make minerals processing environmentally friendly. The use of electrical comminution for processing complex ores is investigated within the ELIZE research project funded by the BMBF (project No. 033R161 A) and industrial partners. The main objective is the development of an industrial scale electrical comminution machine. The first development stages include the investigation and characterization of the electric impulse induced weakening on rocks and ores. The characterization results of the preliminary trials at the microstructural scale on granite, skarn and greisen will be presented and discussed in this article. INTRODUCTION The pioneer work in the area of electric impulse technology was conducted by Russian researchers about 60 years ago [1]. While there have been some successful attempts to transfer this technology into practical applications, such as rock processing [2], laboratory processing of mineral ores [3–5], recycling [5] and geothermal drilling [6–9], the jump into practical industrial large scale application has not been accomplished yet. The Institute of Mineral Processing Machines of the TU Bergakademie Freiberg currently leads a project which can be seen as the next logical step for the technology transfer to industrial applications, namely, the development of continuously operating complex ore processing machines based on the electric impulse technology."

Jan 1, 2018

Since 1992 the Grasberg Mine, located in the remote regions of Indonesia, has utilized the Modular Mining System. Over the last several years, major steps have been taken to maximize this productivity enhancement system. These steps include; the Automated Lineup, the Linear Program upgrade, tracking of Mean Time Between Failure, a MEDS system interface, a VMIS system interface, and implementation of the new Graphical Operator Interface Console with Global Positioning, This application of new technology and innovation has lead to improved performance, understanding and reporting, as well as the quality of the Indonesian Engineers. These efforts have contributed 10 Grasberg achieving one of the lowest mining costs in the copper industry.

Jan 1, 1998

By P Christen, D R. Ashley, G R. Power

The Ernest Henry Mine is currently a copper-gold open pit operation situated in north-west Queensland, Australia. It is owned and operated by Xstrata Copper with a current throughput of 11 million tonnes per annum; however, open pit operations are scheduled to cease in late 2011. The deposit dips at approximately 45¦ and extends for at least another 400 vertical metres below the final 530 m deep pit design. Resource drilling from 2002 until mid 2008 has enabled an Indicated Mineral Resource to be established to 1000 m below surface. Scoping and prefeasibility studies (PFS) have been completed toward determining if this resource is suitable for underground mining and a feasibility study is currently progressing with a sublevel caving (SLC) concept. This paper briefly describes the process by which the SLC method was selected, conclusions regarding the non-selected methods, and then discusses the optimisation process used to derive the mining plan. The key optimisation parameters include the production drive spacing, level spacing, draw strategy, cut-off grade and production rate. Key risks will then be assessed and economic sensitivities studied. Final sensitivities will use Monte Carlo simulations to improve the transparency of the projectÆs risk profile. The feasibility study (FS) began in March 2008 and this paper describes the main optimisation steps at the time of writing and outlines the plan for study completion through to March 2009.

Jan 1, 2009

By G. Y. He

The large-scale 8.53m×3.96m (28?×13? F/F) SAG mills was first applied in Donggua Hill Copper Mine which processes 13,000 tons ore per day. The crushing and grinding circuit went into operation in the Donggua Hill plant in October 2004. However, at the beginning, the productivity of grinding only reached 58% of the capacity expected and some indexes of the crushing and milling circuit didn?t meet the requirements. Especially, the total load of the 8.53m×3.96m (28?×13? F/F) SAG mills was up to 34%~41% (25%~30% designed)and some hard rocks with the size of 25~70mm, which can?t be treated as a medium or even would be crushed and make larger ores or steal balls necessary, were seriously accumulated in the SAG mills. Consequently, they occupied the effective mill volume which in turn reduced the efficiency of the SAG mills and increase the energy consumption. In order to solve the problem of accumulation in the SAG mill and increase its productivity, some measures were taken, such as passing more hard pebble through the grate at mill dis-charging end, changing the type of steal balls and so on. And the results showed that these measures functioned well and had good effects, which is that the filling percentage of the SAG mills has been reduced to 26%~29% from 34%~41% with the composition of particle sizes improved a lot and the productivity increased by 77.4% reaching up to 13,380 tons per day.

Jan 1, 2014

By Tony Francelj, D. Scott Scovira, Remi Proulx

The Meikle Mine is a high-grade, underground gold mine that utilizes a primary and secondary stoping method with delayed backfill. The newly developed Rodeo Mine will start production using similar mining methods in late 2001. The combined production for the mines will be 4100 stpd of ore in 2002. Dilution of the secondary stopes resulting from blast induced overbreak of the backfill placed in the primary stopes was an issue identified as being a major contributor to the total mining cost at the Meikle Mine. To address the overbreak issue, a low-density, polystyrene enhanced bulk emulsion was developed and introduced to the mine. The density and energy of the emulsion was varied until an optimal level was reached. The use of a low-density bulk emulsion has greatly reduced the overbreak of the primary stope backfill when blasting the secondary stopes. Benefits to the mines include reduced secondary stope dilution, lowered total mining cost, and increased revenues.1

Jan 1, 2002