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In underground ore mining of copper ore, lead-zinc ore, tin ore and fluorspare in German Democratic Republic geological situation is characterized by ore deposits of small thickness and great variability of ore grades and mining conditions. For long range mining strategy and short-term planning of production a model was developed fitting to make optimal economic mining decisions. Starting point of the model is a cost function representing all direct costs per unit recoverable metal in concentrate for each stoping unit (ore reserve block). In the costs function the results of regression analysis of ore grade and metal recovery in concentration plant were considered. All stoping units (ore reserve blocks) of a mine were arranged to growing direct costs. The relationships of recoverable metal, ore tonnages and corresponding costs were plotted in a diagram. The data processed by- computer and the graphic representation of the results make possible 1. economic evaluation of stopes and ore reserve blocks, 2. estimation of cut off grade, 3. optimization of works planning.

Jan 1, 1977

The process of resource estimation of large precious metal deposits is illustrated by reference to major deposits now being mined or developed by Placer.The estimation procedure commences with building an appropriate model of the mineralization and proceeds through steps of data validation and geostatistical studies. It is important that the geologists most familiar with a deposit be involved with all stages of the estimate, and also prepare a manual estimate used to validate the kriged resource.Resource estimates are major exercises taking many man-months of work. The most time consuming part of this is usually construction of an appropriate three dimensional geological model. The data base for the resource calculations must be complete and checked for accuracy. The most appropriate estimation method must be selected.

Jan 1, 1990

The factors affecting performance of base and precious metal smelting and converting processes are considered in relation to reactor characteristics. The chemical differences between processes are related to these factors for different reactor systems. The complete smelting and converting flowsheet involves a number of operations. The process selected for a particular feed and product requirement should be one which optimises the efficiency of the process, the cost of building and operating the technology and the long-term maintenance and productivity of the units.Ausmelt's approach to achieving an efficient process using its technology is described in relation to the smelting of copper concentrates for production-of blister copper.

Jan 1, 1992

By Loo R

The Paper discusses the size and extent of in-pit dust suppression problems created by iron ore mining in the Pilbara region of Western Australia. Dust problems associated with drilling, loading, hauling and tipping are discussed indicating the large quantities of water which can be applied for dust control and attempts that have been made to rationalise this water usage to obtain maximum benefits from the applied water. The magnitude of the problem and the quantities of water involved can be appreciated when one realises that 275 000 tonnes of rock are moved on Mt. Whaleback each day and that there are 40 km of haulroad within the open pit. Initially dust suppression was limited to the spraying of haulroads by large water tankers. Now dust suppression is practiced during drilling and after blasting, wind blown dust is reduced by application, using water cannons,of large quantities of water to floor stocks prior to loading operations as well as by the installation of 16 km of automatically controlled fixed sprinkler reticulation on the main semi-permanent haulroads. The methods used to assess the water requirements for in-pit dust suppression are discussed and the extensive development testing used to evolve the present installations are 1. Environmental Superintendent Mt. Newman Mining Co. Pty. Ltd. Newman, W.A. 2. Chartered Consulting Engineer, Perth, W.A.

Jan 1, 1979

Around no subject of technical )uterest have prejudice and wrong-thinking in the past so wrapped a web of obscurity as that of the corrosion of metals.It is a matter which has primarily concerned the engineer, but the paucity of his training in chemistry and electrochemistry has been the stumbling block to a better understanding of its mechanism.Now that the more important conditions controlling corrosion have been scientifically.established, it can be seen that, with the exception of but a few of the minor points, the electrochemical laws enunciated by Faraday, Helmholtz; Nernst, and others, are sufficient to include all the facts of the process.The word corrosion (derived from the Latin rodere-to gnaw) is so often wrongly applied that a definition at this stage would be useful. As now understood, it means the dispersion and waste of the useful solid metal by conversion into a useless compound which mayor may not be retained on or near the metal remaining.Commonly the presence of these compounds is regarded as evidence of corrosion, but the converse is not necessarily true; the lack of visible corrosion products on a clean surface of metal is no criterion of the absence of this change. It may be difficult to prove that the erosion of such a surface has been caused by chemical and not by mechanical effects alone.

Jan 1, 1932

North Broken Hill Limited came into prominence as a producing mine at· the commencement of the present century, when a great many of the disabilities experienced in earlier mining operations th:rough lack of adequate stope filling had been overcome.The northern or narrower ore-body was first mined in the upper levels and, in the early stages, no great difficulty in mining was experienced. In depth, under the influence of its northerly pitch,. the wide southern ore-body entered the North mine between the 400 and 500-ft. levels. Owing to its flat dip and the relatively weak nature of the hanging wall and footwall, the value of close filling was recognized and this policy has been followed throughout the life of the mine. This feature undoubtedly contributed to the freedomfrom "creep" action to which some of the older mines had been subjected.The Broken Hill lead-zinc-silver ore-bodies occur as well defined replacements of favou:rable horizons, in intensely folded Pre-Cambrian sedimentaries. In the North mine two main replacement zones occur, the Gre being found where the beds are involved in a certain set of minor folds. The resulting ore-bodies are roughly elliptical in cross-section, the long axis of one being north-east of, and somewhat offset from the long axis of the other. The ore-bodies pitch eastwards at 40° and dip northwards at 60° in a fairly regularmanner. The southern Ore-body has an average length of 700 feet and an average width of 90 feet with a maximum width of 230 feet, whilst the nonhern ore-body on the lower levels averages 500 feet long and 40 feet wide.

Jan 1, 1940

By R McConnochie, J V. Rowland, J L. Mauk

The Sovereign prospect in the lower Waitekauri Valley of the southern Hauraki Goldfield occurs in daciterhyolite flows and volcanic breccias of the Waipupu Formation. The lower Waitekauri Valley contains a series of NE to NNE-trending normal faults, and the Sovereign prospect lies in a NW-striking graben. The structure of the Sovereign prospect is complex. NE to NNE-trending veins and normal faults dominate the area, however WWNW and N to S-trending structures occur locally. Kinematic analysis of these structures indicates predominantly dip-slip movement, with a local strike-slip component. At least two sets of veins occur in the area: 1.        steeply dipping veins; and 2.       low angle veins, which cross-cut and locally offset the steeper dipping        vein set. Mineralization appears to have formed during normal faulting in an extensional regime.

Jan 1, 2007

Many problems result when coal mine shafts are built in complicated geological conditions and serious shaft lining ruptures have often occurred in the eastern part of China since 1987. Grouting is applied as one of the major measurements for shaft lining ruptures. However, as the general location of reinforcement grouting for shaft lining is deep in or near the bottom aquifer, while using cement grout as the grouting material, the grouting mostly belongs to fracturing grouting in deep alluvium. In these conditions, the mechanism and behavior of fracturing grouting has not yet been understood. From these points of view, this paper describes the mechanism of shaft lining rupture and fracturing grouting and then discusses the effect of grout injection on the stability of shaft lining by means of numerical analysis and field data obtained so far.

Dec 6, 2010

By Sinha DK

Coal Mining in India had been confined in the past primarily to two or three coalfields. Unscientific mining has led to huge degradation of land including massive subsidence of strata and disturbances of water tables to a wide extent. This has caused problems not only in flooding of mines from surface water but also in further planning of the surface drainage for current mining activities. Now, therefore, surface hydrology and land-use potentialities of the area have been endangered inflicting severe damage to the overall environment and ecology of the area. The paper Discusses certain investigative aspects of the problems highlighted as above in one of the coalfields, and encompasses mainly the following areas : 1) Quantitative estimation of the damage already done to the natural surface drainage system. For this purpose damage to topography and drainage for the last fifty years have been made out through the aerial photographs and topographic map sheets 2) Analysis and comparison of different states of such photographs are carried through to indicate the extent of damage to the hydrological conditions inducing undesirable changes in its land-use pattern. Based on the analysis, concrete suggestions are made to restore the water drainage system which will be most suitable for future mining in the area containing high grade coal. The design and planning of the drainage system is based on the total system approach including the cost benefit analysis as well as hydrological considerations.

Jan 1, 1988

By Wang Y. J

This paper describes a more generalised or generic approach for the mine ventilation network problem. More specifically, it defines the network variables in a manner that establishes the network problem in a nonlinear programming format. Assigned to each branch are three variables: air quantity, regulator pressure loss and fan pressure. Each variable is imposed with lower and upper bounds. Based on these, the generalised network problem for a mine ventilation network with B branches is presented as a system of B independent network equations in 3B unknowns (variables) with variable bound restrictions, and it is classified as a nonlinear optimisation. A nonlinear programming model has been developed for this generalised network optimisation problem. The model is formulated and transformed into a standard equality-constrained nonlinear programming form with given variable bounds. Then, MINaS (Modular In-core for Nonlinear Optimisation System) is used to obtain solutions. Examples are given to illustrate this nonlinear programming approach to the mine ventilation optimisation problem.

Jan 1, 1993

The Vertical Crater Retreat (VCR) mining method was used to mine two rib pillars at New Broken Hill Consolidated Limited (NEHC) mine at Broken Hill. Experience gained in a trial VCR pillar stope was applied to the design of Panel 3CN pillar (P3CN). Restricted access and a central sandfilled plug in this pillar necessitated the use of angled blastholes and blasting of the stope in two sections. Borehole surveys and close charging supervision were necessary to block, charge and stem the spherical charges in the correct position. The laver sections of the VCR stope with rock walls attained an average slice advance of 2.2 m whereas the higher section of the st.ope between cemented fill walls attained an average slice advance of 3.4 m. Achieved fragmentation was extremely fine. External dilution was assessed at less than 10 per cent. A cement consolidated sandfill exposure of approximately 1300 m2 stood vertically with no significant slumping.

Jan 1, 1983

The search for an efficient and economic machine to excavate hard rock continues. Development of the Robbins Mobile Miner commenced in 1983 with the formation of a joint venture between Mount Isa Mines Limited and The Robbins Company. Construction of the machine ensued and preliminary trials to verify the cutting action were undertaken in the USA prior to transportation to and assembly at Mount I-sa where mining commenced in September 1984. Initially, the machine was used to develop the S60 Decline which serves as a combined access and conveyor drive for the Southern 1100 Orebody Ore Handling System.

Jan 1, 1988

By Giannini L. M

Optimisation techniques, based on the block model, for solving the optimum pit limit problem were discussed in an earlier paper. Of the available techniques the one based on graph theory proved to be the most attractive. In the graph theory model the vertices represent blocks and the arcs represent the mining restrictions. For large ore-bodies direct application of the graph theory method poses considerable computational and storage problems. Techniques for easing the computational effort by reducingthe problem size were introduced in an earlier paper. Further, significant computational savings can be made by exploiting the structure of the graph. This is done by building the graph up level by level and successively applying the graph theory algorithm to reduce the number of blocks. In building up the graph in this way one needs what is called a "search pattern" to indicate which arcs are to be added as new vertices are introduced. Moreover, as it is essential to keep the number of arcs to a minimum it is necessary to establish a "minimum search pattern".The problem of determining minimum search patterns for any block model and for any wall slope restrictions has not been considered in the literature.The objective of this paper is to present a complete solution to this problem and to discuss, through typical case studies, the application of the associated software developed.

Jan 1, 1988

By N Tuffs, R Peace, S Xue

Mine gas control is a major issue in most of the gassy underground coal mines, due to its direct impact on safety, production delays and cost of production. Analysis of the gas data, from different collieries in Australia showed that longwall gas emissions have increased substantially over the years. Simply increasing the number of goaf holes in the panel or decreasing goaf hole spacing seems not to be effective, in controlling high goaf gas emissions. A major research project has been undertaken by CSIRO in collaboration with mine sites to address this goaf gas control issue with the aim of developing effective and optimum goaf gas drainage strategies. The project has combined extensive field studies with computational fluid dynamics (CFD) models, to characterise goaf gas flow patterns and develop effective gas control strategies. The research work specifically involved review of gas control issues at field sites, goaf gas monitoring, tracer gas tests, CFD simulations and extensive field trials. Field demonstration studies of the new optimum strategies have been conducted at two collieries in Australia. The project results have shown that the optimum strategies were highly successful, in improving the overall efficiency of goaf gas drainage systems, at both the field sites. Results of the goaf gas flow characterisation studies and field demonstration studies are summarised in this paper.

Jan 1, 2005

In an earlier paper(l) details of a laboratory method of extracting and separating tantalum and columbium oxides from tantalite have been given. In view of the fact that Australia may have need to be self sufficient in this field it was decided to erect a pilot plant for the production of tantalum oxide in the Metallurgy School, University of Melbourne. The plant was designed for treating about 40 lb. of ore in a batch over a period of two weeks, although; because of the sectionalized nature of the process, the capacity of the plant was 40 lb. ore per week.Australia is fortunate in possessing some very rich tantalite and columbite deposits, particularly in the Pilbara District in Western Australia. The ore used in this work was obtained from a small but high grade deposit near Greenbushes, Western Australia, and consisted of lumps, weighing up to 8 lb. each, of almost pure ferro-tantalite with occasional thin veins of the very' rare' mineral stibiotantalite.The main constituents were:

Jan 1, 1946

By L S. Barbour, M K. Meiers

Soil covers for mine waste are subject to changes in structure as a result of root development, and wet/dry or freeze/thaw cycling. The purpose of this study was to evaluate the changes in the hydraulic conductivity of three non-compacted clay covers over time. The covers are located on a sodic/saline overburden fill (30-Dump) at the Syncrude oilsands mine in Fort MacMurray, Alberta, Canada. Monitoring of these covers for temperature, matric suction, and water content by the University of Saskatchewan has been ongoing for more than three years. The three covers (D1, D2, and D3) were constructed in 1999 and are 50 cm, 35 cm, and 100 cm thick. The covers are comprised of a surface layer of reclaimed peat/mineral mix over a secondary reclaimed mineral soil (glacial till or glaciolacustrine clay), placed over a sloping shale surface. Field measurements of hydraulic conductivity within the secondary layer were obtained using a Guelph Permeameter during the 2000, 2001, and 2002 summer field seasons. Repeated measurements were made within the D1, D2, and D3 covers at depths of approximately 40 cm, 30 cm, and 60 cm, respectively. The values of hydraulic conductivity for the covers were similar to each other during each of the field study seasons. The mean hydraulic conductivity of the secondary layer increased every year: 2.5 + 10-6 cm/sec to 2.1 + 10-4 cm/sec to 4.3 + 10-4 cm/sec from 2000 to 2001 to 2002. Soil temperature data shows that one freeze/thaw cycle occurred each year at the measurement depths.

Jan 1, 2003

By Wright S, Jorgensen F. R A

The reaction between lead sulphate and a number of base metal sulphides (galena, sphal- erite, chalcopyrite and synthetic pyrrhotite was studied as a means of desulphurizing lead sulphate containing fumes and residues to levels acceptable as ISF feed. The reactants were mixed with 50% zinc oxide to act as a "basket" to contain the molten products of the reaction and pressed into small briquettes 20 mm in diam. Factors such as temperature, time and the composition of the atmosphere were investigated. Using the PbS/PbS04 system as an example it was shown that the reaction became rapid above 800¦C and that both sulphur dioxide and oxygen in the atmosphere were detrimental to achieving low sulphur in the product. In an inert atmosphere all the sulphides when roasted for 1 h at 1000¦C gave results corresponding to the elimination of more than 95% of the sulphur in the reactants. Leach plant residues were considered for use as the "basket" material. It was shown that the residual sulphide and sulphate components of the residues underwent similar reactions to those experienced by the pure systems.

Jan 1, 1987

By N R. Johnson

The overland conveyor at the Los Pelambres mine in Chile is designed to move 8700 t/h of material over 12 km at a speed of 6 m/s while descending 1400 m. The conveyor, which is divided into three segments, is equipped with a braking system that must bring it to rest without producing excessive stresses in the conveyor belt. Retardation and gently stopping a mass of 250 t requires retardation times in the order of 60 seconds. Brakes that can provide this performance require sophisticated controls as well as very high heat absorption capacity. This paper describes the thermal analysis of the braking system, which required the use of novel materials to meet the arduous duties imposed on the callipers and discs.

Jan 1, 2005

By Sirayanone S, Rashad MZ

An important problem occurring in the iron and steel industry of Egypt is the presence of manganese oxide and chlorine with different percentages in the Bahariya Iron Ore Deposit, Western Desert, Egypt. In this work we used a geostatistical method known as the Volume- Variance Relationship to predict grade fluctua- tions of Fe% , Mn% and Cl% in the ore after blasting a certain volume from the ore deposit, on the other hand, if we have a certain limit for each of these chemical components, we can select the bench blasting dimension to give these limits.

Jan 1, 1986

By P S. R Reddy, V N. Misra

The iron ore deposits in India are rich in iron content but usually contains high alumina and silica. The current industrial practice results three products namely lump, fines and slimes. The lump and fines with or without beneficiation are directly fed to the blast furnace and sintering plant respectively while the super fines or slimes are presently discarded as tailings. Around eight million tonnes of iron ore slimes estimated as being 15 - 20 per cent by weight of run of mine ore containing ~48 - 62 per cent Fe, is discarded every year causing huge loss to the Indian iron ore industry. In addition, these slimes stored in massive tailing ponds pose enormous environmental and ecological problems. Extensive investigations have been carried out on three iron ore slimes generated at Barsua, Bolani and Meghahatuburu iron ore mines of India. The studies include physical, chemical, mineralogical characterisation and beneficiation studies adopting conventional hydroclyclone and wet high intensity magnetic separator. The characterisation studies have indicated that most of the gangue minerals are accumulated in finer fractions. The studies on hydrocyclone and magnetic separation had indicated that an iron concentrate of 61 - 65 per cent Fe could be obtained by recovering 59 - 78 per cent of the iron values present in the slimes. Depending on the nature of the slimes the alumina and silica levels have been brought down to 2.5 and 1.0 per cent respectively. The effects of different operating and design variables along with detailed characterisation studies have been highlighted.

Jan 1, 2002