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By Kim M

Mukuk gold mine in South Korea produces a pyrite concentrate containing gold associated with arsenopyrite as a gangue mineral. The effects of Portland cement as a depressant on the flotability of arsenopyrite were studied to improve the separation of arsenopyrite from pyrite concentrate containing gold. A series of the fundamental flotation tests were performed using Portland cement as a function of pH and concentration of the collector. Flotation recovery of pyrite and arsenopyrite in the fundamental tests with amyl xanthate showed that arsenopyrite was depressed by the addition of a moderate amount of Portland cement, but pyrite was not depressed by it. In the flotation tests of the artificial mixture samples with arsenopyrite and pyrite, following pH were adjusted to be 10.5 by Portland cement, different amount of amyl xanthate was added. The results from these studies showed that flotation recovery of pyrite was 100 per cent under the condition of some addition of amyl xanthate, but arsenopyrite was not floating at all. Portland cement shows remarkable depression of galena, but its effect on the flotability of chalcopyrite is not as clear. In the pulp under Portland cement addition, chalcopyrite can be easily activated by the addition of sodium bisulphite, whereas galena is depressed more effectively. From the batch flotation tests with the pyrite concentrate, the galena concentrate and the Cu-Pb bulk concentrate from the mines, it was confirmed that the results of the batch flotation tests agree with the results of the fundamental flotation tests. The effects of depression by Portland cement on pyrrhotite, marmatite and stibnite are also discussed briefly.

Jan 1, 1993

By Gang L

Seventy-nine gold deposits and prospects have been discoveried in the Jiamusi region of northeast China, and constitute one of the most important gold metallogenic belts in China. All these endogenic gold occurrences can be subdivided into three main deposit types: (1) porphyry related; (2) metamorphic-intrusive hosted, and (3) sediment-hosted deposit. The first two types of gold deposit are spatially and temporally related to Mesozoic Yanshanian granitoid intrusions with hydrothermal activity channelled along crustal-scale fissures. The ultimate cause of the Yanshanian magmatism is considered to be the subduction of Pacific oceanic lithosphere beneath the Eurasian continent. In contrast, The chemical sediment-hosted deposit is typified by the Dongfengshan gold deposit, and genetically related to Proterozoic sedimentation and Mesozoic igneous activities.

Jan 1, 1995

Mineral resource estimation is commonly based on the accumulation of a series of local estimates. At times, the distribution of these grade estimates is not appropriate to the grade distribution of the data on which the estimates are based. Mineral resource grade estimation has an increased potential of being in error as the grade variability increases. As the mineral commodity value increases, greater grade variability within the mineral resource is tolerated. This paper directs its attention to mineral properties where the data average grade is 20 per cent or more than the data median grade at a specific cut-off grade. A mineral resource estimate is enhanced if it is supported by graphs which demonstrate that the sample data have been separated into appropriate geological domains. Each geological domain has a unique grade distribution signature, which can be graphically demonstrated simply and objectively. This signature will usually be evident well before the Indicated mineral resource estimates are available. The paper looks at the use of the log probability and MedAve plots to assess how effective domaining has been. It further outlines how the MedAve plot can be used to assess the integrity of the mineral resource grade estimate within a geological domain with the data on which it is based. The paper suggests that the overall grade of a mineral resource at any cut-off grade will be closer to the data median grade rather than the data average grade. Tips are provided to ensure that the odds reflected in the data grade distribution are not ignored and hence the risk that the project is affected by unrealistic estimates of the overall mineral resource grade is reduced.

Jan 1, 2003

It is suggested that if adequate knowledge is available about classifiers in closed grinding circuits, these units may be used as on-stream size analysers when equipped with suitable sensing devices. Research work which is at present in progress to enable a hydrocyclone to be used for this purpose is discussed.

Jan 1, 1967

Over the past 18 months the De Beers Consolidated Mines Ltd operations have made a concerted effort to move away from using the traditional shock tube initiating systems. These systems are being systematically replaced by the use of electronic delay detonators (EDD). Various trials were conducted in both host rock and kimberlite rock masses to improve tunnel advance as well as to optimise delay timing during trough openings (Ngoma et al, 1999; Mohle, 1999; Baltus, 2000). The high cost of EDDÆs, when compared with traditional initiation systems, led to a number of detailed studies being conducted on the mines where EDDÆs were being used. These studies aimed to quantify the additional benefits when blasting with electronic detonators. The studies showed that the change was justified on the basis of increased quality control and reliability gained through the use of EDDÆs. However, these benefits attract other related benefits, like fragmentation control, and backbreak reductions. When compared to the shock tube initiating systems the increased development face advance and the reduction of oversize during production blasting using EDDs, compared favourably to the less costly systems. As blasting engineers gained experience and confidence in the use of the system bigger blasts were initiated in mass under-cut blasts and slot raise development, by using multiple hole firing and second delay periods between holes. In the open pit and sublevel open stope mining methods the control of the fragmentation distribution and the effect of the mass of explosive detonated during a blast is detrimental to the loading and hauling production rates and the stability of the rock mass behind the blast. With a stable rock mass the bench cutting can be executed to establish steeper overall slope angles leading to large cost savings due to a reduction in waste stripping. It is the purpose of this paper to indicate through quantification that the use of the EDDs as an initiating system improves all-round blasting performances and assists in meeting customer requirements. The customer being the ore treatment plant.

Jan 1, 2001

By U Dzharlkaganov, B Bekmurzayevand M

The principle conception is presented of timely planning of winning operations in complex-structural blocks and faces in week-24-hourly regime. For adequate description of complex interconnections of open cast operation in space and in time and solving of optimisation problems in timely regime it is necessary using of complex logical and calculation procedures.

Jan 1, 2003

A method of assessing the blastability of a rock mass is presented which makes use of five, readily available, simple parameters. These are the Rock Mass Description, Joint Plane Spacing, Joint Plane Orientation, Specific Gravity Influence and Hardness. For a particular rock mass a value is assigned to each parameter and the Blastability Index is calculated from these values. Application of the Index in blast planning and computer modelling is discussed.

Jan 1, 1986

When a fire or explosion occurs underground the ventilation maybe disrupted and the atmos- phere may become oxygen deficient and filled with noxious and flammable gases. The basic survival technique for:any man alive underground is to escape and this may be achieved and rescue workers may enter such atmospheres to carry out rescue work underground by using appropriate breathing apparatus.

Jan 1, 1983

A computer programming language known as GPSS is described and possible applications for the mining engineer are presented. The language is continually being upgraded with improved versions appearing about every three years. The tremendous power of the language is considered by comparing it with standard engineering programming languages, such as Fortran or Basic. Sample problems that can be solved using the language are indicated. The advantages and disadvantages of the languages are also discussed.

Jan 1, 1987

The title of my address today is "Oil and Gas Valuations - A Simplistic View of Some Critical Issues". Alternatively I could have called this address "Pitfalls for investors' and corporates in accessing Independent Experts Reports" 'as in this brief 12 minute talk I will briefly comment on some common misconceptions with regard to the valuation of exploration areas and production interests, and comment on how the draft release guidelines address these issues.

Jan 1, 1989

By Middlebrook PD

The problems of education and research in the extractive metallurgy area are being tackled by the University of Melbourne through activities centring on the Department of Chemical Engineering. The establishment of the G.K. Williams Laboratory and the enhance- ment of the teaching of material relevant to extractive metallurgy in the Chemical Engineering course aim-at providing graduates and experienced researchers for the industry and at providing a strong research group carrying out industrially significant research in the area of pyrometallurgy.

Jan 1, 1986

By Tilyard P. A

Pasminco has tested a Valmet ES1 ceramic disc vacuum filter at its Broken Hill concentrators. On lead and, particularly, zinc concentrates at the ZC Mine the filter performed well but on North Mine lead concentrate problems were experienced with deposition on the disc, which resisted both ultrasonic and acid cleaning. A preliminary financial analysis showed that the application of the filter at the ZC concentrator was worth pursuing. Accordingly an ES30 machine has been hired for plant evaluation.

Jan 1, 1989

By Ryan CG, Cousens DR, Suter GF, Griffin WL

A novel method utilizing PIXE with microbeams following fire-assay has been developed to determine PGE and Au at sub-ppm levels suitable for application in exploration. Analyses of the prills from the lead and silver fire-assay yield Pt, Pd and Au concentrations readily. NiS must be used as collector if the complete suite of PGE is required, but this method is not as Convenient.

Jan 1, 1989

By Lewis RW, Wilson GI

An ore reserve estimation is only as meaningful as the quality of the data used. All required information needs to be collected in a careful and systematic manner, and be rigorously checked and verified before estimation commences. In addition to geological, assay and location data, a large variety of other information is required for the estimation process. This includes mining, metallurgical and environmental parameters. Though outside their usual area of responsibility, geologists should be involved in the selection and collection of this additional Information.

Jan 1, 1987

The Plant Control and Data Logging System for the Loy Yang Open Cut (LYOC) is part of a control and communications network designed to provide a high level of surveillance of open cut plant and facilitate the efficient co- ordination of operations and plant maintenance. The computer system selected utilises a central dual mini-computer and multiple microcomputer data transmission network ,linked to the plant controllers using distributed, microcomputer based remote data collectors or outstations. Several aspects of the computer system are outlined.

Jan 1, 1982

Mine planning for ore recovery by open stoping and pillar recovery is becoming more sophisticated, but there are basic operating constraints which must be imposed if this planning is to realise the production results on which the mine is dependant. The production reliability of an open stope is usually a high priority and common design problems can be identified. A range of practical considerations which should be considered at the mine planning stage are reviewed including equipment performance, blasting technology, ventilation requirements, development layouts, lead time, ground conditions, support, backfilling and ore recovery.

Jan 1, 1982

The north-eastern half of the Yilgarn Block of Archaean Rocks lies in the and zone of Western Australia. In recent years a large number of gold mines have been established there, all requiring water supplies from local groundwater. The groundwater sources that have been utilised canprise bedrock, pre-Quaternary channel deposits, and Quaternary alluvium. In the search for groundwater each type of occurrence is considered, and the choice is made on the supply potential and logistics. This paper deals with groundwater in bedrock. Using examples, sane principles of the geology of groundwater occurrence are illustrated.

Jan 1, 1988

By Wernick B. J

Recently, the Environmental Engineering Laboratory of the Chamber of Mines of South Africa Research Organization has made signifi- cant progress in the development of more accurate algorithms for assessing heat flow in gold mines. These algorithms have been incor- porated into an overall computer program, ENVIRON, which enables the complete thermo- dynamic analyses of mine ventilation and cool- ing systems to be carried out. Recently, efforts have concentrated on the development of an expert computer system which will guide engineers in the process of selecting the most appropriate environmental control strategy.

Jan 1, 1988

Operation of the tankhouse at the Electro lytic Refining and Smelting Company's works has been improved, but further automation is re- quired to cut the labour intensive nature of the routine tasks. Anode quality, both chemical and physical, plays an important role in efficient refinery practice, and impurities such as lead, antimony and nickel have required careful monitoring for smooth operation. The gradual replacement of copper blanks by titanium has markedly improved the quality of starting sheets, but problems have been ex- perienced with surface preconditioning of the titanium blanks. Polishing with emery paper proved to be a successful technique.

Jan 1, 1976

By Toffeg A. N, Abdul-Hameed I

More than 1000 Ian of seismic reflection data correlated to ten exploration wells along with geological, gravity and magnetic data are used to construct the subsurface structure, in particular the crystalline basement, along a corridor approximately 100 Ian wide that traverses central Iraq in SE-NW direction for a distance of about 500 km from Baghdad in the central part of Iraq to Dohuk near the Turkish border. This transect is one of few such transects that represents the Iraqi contribution to the Global Geoscience Transects (GGT) project. The transect crosses two out of three major tectonic elements of Iraq: the unfolded zone and the folded zone.

Jan 1, 1990