Search Documents

By Ono K, Oishi T

Electrochemical determination of the oxy- gen partial pressure in the Fe-0-SiO 2 ternary systems saturated with solid silica was done by measuring the activity of oxygen in a silver bath in equilibrium with the molten slags using zirconia solid electrolyte galvanic cells. From the data obtained, the activity ~Faii.st composition relations were calculated

Jan 1, 1980

The Government Mining Engineer of South Africa has decided to legislate that Self Contained Self Rescuers (S.C.S.R.) become a mandatory piece of equipment for all those persons proceeding underground. It is envisaged that: * employees in underground coal mines will be fully equipped with S.C.S.R.s during 1988; * those persons employed in gold mines during 1988/89; and * personnel in all other mines by the end of 1990. It is the intention of this paper to discuss the introduction of these auxiliary life support systems, and to give an update on current market developments.

Jan 1, 1988

By Krouse RH, Aleinikoff JN, Nokleberg WJ, Church SE, Newkirk SR

A belt of volcanogenic massive sulfide (VMS) deposits and occurrences extends for over 150 km along the southern margin of the Yukon-Tanana terrane in the eastern Alaska Range. The VMS bodies occur mainly in the Jarvis Creek Glacier subterrane (JCGS), one of the highest structural/ stratigraphic levels of the Yukon-Tanana terrane. The JCGS consists of a VMS--bearing metavolcanic rock member and a metasedimentary rock member. The VMS deposits and enclosing rocks exhibit two periods of regional metamorphism.From northwest to southeast, the major VMS districts are the Bonnifield, Hayes Glacier, McGinnis Glacier, and Delta districts. The Bonnifield, Hayes and McGinnis Glacier district sulfide bodies consist of pyrrhotite and lesser amounts of pyrite, chalcopyrite, with or without arsenopyrite, sphalerite and galena. The larger, 800 km Delta district deposits and occurrences contain variable amounts of pyrite and pyrrhotite and lesser amounts of primarily chalcopyrite, galena, sphalerite, and arsenopyrite.The sulfide accumulations are interpreted as Kuroko-like deposits that formed along the submarine volcanic part of a Devonian, continental-margin igneous arc. U-Pb isotopic data from zircons from the metavolcanic rocks indicate an age of about 370 Ma (Devonian). 207Pb/204Pb ratios for sulfides from the districts are similar and indicate lead was in part derived from first cycle sediments eroded largely from Precambrian crystalline rocks. 207Pb/204Pb ratios from feldspars in Devonian metavolcanic rocks are similar to those in sulfides, and indicate incorporation of radiogenic Precambrian lead into the Devonian magmas. A Precambrian crystalline source for quartz in metasedimentary rocks is indicated by 2.3 Ga old zircons. Common-lead isotope studies of igneous phenocrysts in metaigneous rocks and sulfides in volcanogenic massive sulfide deposits indicate a unique isotopic signature. The data permit an exotic origin of the Yukon-Tanana terrane with respect to North America.

Jan 1, 1990

By Anderson JDC

Opencast Lignite Mining requires topwall strata of seams to be fully depleted and footwall aquifers sufficiently depressurized. To prevent a spread of the cone of depression into protected wetlands some distance away, alternatives had been investigated such as closing water works, underground slurry wall barriers and recharge by infiltration. As a result of these investigations, the infiltration method has been chosen and in a first phase during the next decade it will utilize as much as 55 x 106 m3/year. Using this approach, the survival of the wet lands is assured.

Jan 1, 1988

Spatial data processing using geographic information systems produces qualitative results which are superior to those from other existing software tools. However, the answers to various quantitative questions in mining operations is often limited by the capacity of the GIS to process appropriate spatial data. The efficient operation of a large underground mine demands that an adequate GIS be put in place.

Jan 1, 1995

By Sullivan TD, Redman PG

AND INTRODUCTION The Lochiel coal deposit, a large Tertiary soft brown coal deposit in the mid north of South Australia, is currently being investigated by the Electricity Trust of South Australia (ETSA) as a potential source of fuel for a base load power station. Feasibility studies indicated that the proposed dragline method of overburden removal was viable but economically sensitive to both highwail and dump batter angles. The unusual properties of the unconsolidated overburden sediments and the groundwater regime posed a number of intimately related hydrogeological and geotechnical questions which were addressed before and during the excavation of a trial pit. All strata at Lochiel are of soil strength, and artesian aquifers occur above and below the coal. From the initial evaluation of the deposit a number of hydrogeological questions were defined. These related to the rate at which the pore pressure in the silts is reduced by dewatering, the extent of the reduction in pore pressure due to prestripping, and the feasibility of dewatering and depressurising carbonaceous silty sand sequences. The site of the trial pit was selected to answer these and other questions from the basis of a detailed geological, hydrogeological and geotechnical understanding. The trial pit dewatering system simulated a full scale mine dewatering system and included ten pumped wells, twenty drainage wells, and nearly 400 monitoring instruments. It operated from September 1986 to June 1987. The excavation was carried out between February and May 1987.

Jan 1, 1988

By Evans R, McCallum P

Modem blast initiation systems allow users many options for connection and application in the field, and have resulted in more innovative and complex uses of sequencing to influence blast outcomes. However, no tool existed which allowed the blaster to easily and quickly assess the effect of different options. The original requirement was for a computer program which allowed the easy input of blast patterns and the associated initiation sequence, and then permitted the evaluation of different options with respect to established criteria such as the number of holes per delay and angle of initiation. The implementation of this goal saw the development of the SHOTPIan blast sequence design software, with particular emphasis on an easy-to-use menu driven interface and visualisation of the blast sequence. Extensive trialling during development saw the incorporation of additional features requested by industry such as the ability to import from established mine design software packages, and further features such as the calculation of burden relief times. Case studies of the use of the program are provided, where the rapid evaluation of a number of options has enabled blast results to be optimised. Examples are also given of cases involving two-path initiation

Jan 1, 1995

By Hefter G. T, Singh P

The use of sulphur dioxide (SO2) as an anode depolarizer in place of traditional oxygen evolution reduces the energy costs of copper electrowinning. This paper reports the effect of various metal ion impurities, which are usually present in th

Jan 1, 1998

The Circum-Pacific area is one of the most important gigantic skarn-metallogenic belts in the world. In more than 20 coastwise countries of this region, there exist thousands skarn deposits of different types. According to the differences of major metallic elements, the skarn deposits may be classified into seven subtypes, i.e. Fe, Cu, Pb-Zn, W, Sn, Mo and Au skarn deposits. In this paper, the distribution. and geological characteristics of above-mentioned types of skarn deposits are described briefly. Skarn deposits may also be classified on the basis of the dominant calc(magnesian)-silicate mineral assemblages into four types: magnesian, calcic, manganoan, and alkaline skarn types. Magnesian skarns may be associated with Fe, Cu, Au,, Sn, B, Be mineralization, calcic skarns with Fe, Cu, W, Mo, An, Be, Pb, Zn, Sn minerailization, while the alkaline skarns occur in U(Th, Nb) deposits. The skarn deposits of both East and West Pacific rims have many general characters, but have some diferences in geotectonic settings, intensities of mineralization, distribution, and metallogenic epoches. In this paper, the minerogenetic series and the mineralizing specialities of related magmatic rocks of the skarn deposits are also discussed.

Jan 1, 1990

By Bolton G. C

Experiments were conducted to access the feasibility of removing zinc from lead slag by sulfation or chlorination or both. Gaseous sulfation with sulfur dioxide and oxygen released only 50 per cent of zinc even under the most severe conditions. Sulfation with concentrated sulfuric acid by a fast-leach process released 95 per cent of zinc while pug-roasting released a maximum of 78 per cent of zinc. Chloridization with NaCi in the presence of sulfating gas released 50 per cent of zinc, while direct chlorination with chlorine gas and oxygen released 85 per cent of zinc and 100 per cent of lead in a chloride condensate containing little impurities.

Jan 1, 1980

By Hanna P

Coal geologists are under pressure to minimise exploration expenditure, maximise interpretation confidence and produce the results often too soon. This pressure continues to increase as companies are forced to evaluate borderline economic deposits which are usually deeper and more hazardous, such as the Togara North and Togara South projects in Central Queensland.

Jan 1, 1998

By Nightingale RJ

A column (50 cm 4) provided with a bell charging mechanism and a rectangular perspex insert was used to investigate the inter-relationship between charging pattern, size analysis and velocity profile for a number of charging methods. It is shown that a strong correspondence exists between size distribution and velocity profile for bell charged ore and coke and that decreased coke volumes cause higher pressure drops and increased central flow in beds with "V" shaped layers. It is also shown that a bell charged mixed burden exhibits greater segregation than when it is bell charged as layers and that when uniformly charged the mixed burden shows least segregation and a virtually flat velocity profile. A relationship is derived for "V" profile charges showing the extent of central segregation with furnace size.

Jan 1, 1975

The Olympic Dam Mine is a large, mechanised, underground operation currently producing 2.2 million tonnes-per-year of copper/uranium/gold ore. The mine is accessed via one shaft and one service decline. An additional 13 raise bored ventilation shafts have been completed to-date.Ventilation requirements are stringent in order to provide adequate dilution and removal of diesel fumes, radon gas/daughters and heat generated from both engines and wall rock.Due to the nature of the orebodies, the mine workings will continue to expand laterally necessitating the addition of at least one major surface raise every year.

Jan 1, 1992

By Virtanen M

Grinding has been one of the areas of major development at Outokumpu's concentrators. During its early years the company used entirely rod and hall mills, but due to the high costs of metallic grinding it began the testing of autogenous grinding as early as the 1950s. In the late-1970s, the company's own modification for two stage autogenous grinding was ready for industrial use. Surprisingly late, in the 80s - 90s, an interest rose to check also the effects of grinding methods on flotation results. This paper firstly gives a short history of the development work of Outokumpu type autogenous grinding, called 'Outogenius'. The effects of some grinding methods on the process results of two nickel ores are then reviewed. The tests to date show notable effects of grinding methods on flotation.

Jan 1, 1996

By Blair J. R

In the Bayer process, bauxite is leached with caustic soda, forming a solution of sodium aluminate, from which hydrated alumina is precipitated. The efficient operation of the continuous form of this process requires that the concentration of caustic soda be controlled. A computer simulation of the concentration of caustic soda has been conducted to provide information, regarding the dynamic behaviour of caustic concentration, which is not available from normal plant data. The basis of the simulation is a state- space model of an alumina refinery, linearized about the normal operating condition. The formulation of the model, with the relevant approximations and assumptions, is outlined. The simulation of the mudwash section of the. plant is described in detail. A continuous model of the mudwash, having time-varying coefficients, was driven using operating data from an alumina refinery. The modelled response showed reasonable agreement with the recorded plant response.

Jan 1, 1977

By McClarnon D. J

This paper aims to provide the reader with an insight into the field of computer graphics and Virtual Reality (VR), and show how both have been applied to the general area of Free Steered Vehicle (FSV) operations underground. It first explains this developing computer technology and explains its advantages over existing CAD based solutions. This paper deals with the graphical applications and implications of building models within a computer's memory. It then continues to describe the problems with Free Steered Vehicle operations. The work already carried out in the field of VR is explained, and the production of a VR system addressing the problems with fitting cameras to aid the driver's field of view is detailed. Another possible use of VR is also explained - the concept of risk regions, demonstrating its uses in the examination of proposed operational methods. Examples of possible uses are given, and its potential advantages over existing methods discussed. A case study of a computer-generated video involved with the safety of operations of FSVs is also presented. This addresses the precautions that pedestrians should take to ensure safe working in areas where FSVs are operating. This paper then concludes with possible further applications for computer graphics and VR, and the on-going research into these two technologies.

Jan 1, 1995

By Shuqing L

The application of single liquid cement for fracture grouting in base rock may have history more than 120 years. The disadvantage of it is difficult to increase the grouting efficiency, because the jelling time of it is very long and hard to control. The double liquid grout, such as chemical grouts and cement water glass grout was developed at the end of 1960.'s Although the jelling time of this kind of grout can be controlled, it mast adopt double liquid grouting technology, use complicated equipment and is not easy to control component's ratio of the grout. Another disadvantage for chemical grout is high price, and have pollution to environment. OCE series single liquid grout is the effective grout material developed recently by making large efforts in Ohina. Main feature of it is that the jelling time is easy to control, materials from cement and clay are very cheap and without pollution to environment, and the grout can be injected by single liquid technology. The effect of QCE series grout has been proven by its application in China. It can be believed that QCE grout has great economic efficiency and will give a push to develop grout material.

Jan 1, 1988

By Getliffe RK

It is becoming more and more difficult to operate mineral and metal processes profitably, as operating costs rise, quality demands in-crease, international competition becomes more fierce and Government charges remain at their current levels. Profitability today depends upon efficient operations, which can only be achieved through precise and dependable con-trol of each process unit comprising thetotal plant.Modern process control systems utilise distributed architecture with microprocessor-based controllers, data acquisition devices and VDU operator stations. Honeywell intro-duced this control technology in 1975 with the "Total Distributed Control" System. Now, building on the proven performance and re-liability inherent in TDC hiway modules, Honeywell has extended the TDC system to inte-grate both management information and control by providing distributed processing modules on the new TDC 3000 Local Control Network (LCN).

Jan 1, 1985

By Rose CW

Typical rehabilitation programmes for spoil piles and waste dumps in open cut coal mines involve the spreading of topsoil to assist vegetation growth. In the early years of rehabilitation before a protective vegetation cover has been established, this topsoil is susceptible to erosion during rainfall events. Since the long term success of rehabil- itation procedures is sensitive to adequate topsoil maintenance and since, on many mine sites, topsoil is a scarce resource, erosion losses of topsoil (particularly once fert- ilised) can severely restrict rehabilitation Measures.

Jan 1, 1983

By Tyson G. R

A novel system has been developed using computer imaging techniques to make on-line measurements of material on a moving conveyor. Meas- urements of the mass or volume of conveyor materials are important in large open pit mining operations such as those operated by the State Elec- tricity Commission of Victoria (SECV). Such on-line measurements can be used for monitoring and controlling the production and transport of coal or overburden, and to assist in maintaining production levels. This paper describes a conveyor burden volume measurement system which is currently under development at the Research and Development Department of the SECV and although targeted initially for use in the Commission's open cut mines, the system is suitable for use on any open conveyor system. A basic developmental system has been built to demon- strate the viability of the technique used and further work on the system is planned. The measurement technique and the major components which have been developed as part of the system are described, some comparisons are drawn with other existing measurement systems and potential errors and future development are discussed.

Jan 1, 1989