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The high cost of sampling systems is largely due to the fact that indiv- idual mechanical type sampling units must be installed at the discharge end of ore/pulp pipelines, that is, at points where the pipeline discharges into pump sumps or the like. A considerable economic advantage may be obtained in the use of a samp- ling device that can be installed at any point in the path of the trans- porting pipe line. Initial tests on a vertical line with an injection sampler using iron ore concentrates reveal the validity of this type sample versus that taken with a mechanical sampler. A descrip- tion of the injection sampler shows its simplicity of installation, requir- ing minimum downtime on existing lines.

Jan 1, 1976

By Singh RN

Monolithic packing systems have gained in popularity as a gate side packing method. However, there has been no detailed investigation to assess their underground strength behaviour. This work includes the laboratory and in situ investigation for strength behaviour determined on various monolithic packing materials namely Tekpak-XX, Hydropak-20, Hydropak-30, Astrapak-3R, Flashpak, Thyssen pack and Aquablends. A simple technique for assessing the pack strength was developed at the laboratory by using a penetrometer, of which penetration resistance can be directly correlated with the uniaxial strength of the pack. The in situ strength investigations were made on core samples obtained from three pipes inserted inside the pack, while the penetration test were made on the pack surface. The in situ results indicated that the packing material develops an inconsistent strength on various part of the pack which was mainly related to an inadequate mixing of grouts inside the pack.

Jan 1, 1992

The mineralogy of regolith material for which whole rock geochemistry has already been done can be used to better understand/rank the significance of geochemical anomalies. Case studies show that the secondary minerals of the regolith environment have quite different capacities to incorporate pathfinder and target elements, eg hematite appears to be a better host to Pb than goethite and Pb rich alunite-jarosite minerals are a better Ag host than mimetite. Thus correlations between elements in regolith material may be strongly affected by mineralogy. Understanding of the significance of a geochemical anomaly is frequently enhanced by knowledge of the weathering susceptibility of different minerals. For example, when a mineralogical sequence which does not correspond to the expected order is found (eg feldspar overlying weathered material without feldspars) it is possible that transported material is present in the profile. Such mineralogical information is particularly relevant as exploration continues into areas of thick regolith.

Jan 1, 1997

Degussa's PAL-system (peroxide assisted leach) has been proven to be more economical than the conventional cyanidation technique. Significant in- creases in the gold recovery have been reported, accompanied by savings in cyanide. Accelerated extraction kinetics and modified reagent demands necessitate a redesign of the conventional cyanidation plant. The South African Osprey Mine is presented as an example of a successful PAL-application. Based on the plant and laboratory data it is shown that the redesign of the flowsheet can be an important factor for the effectiveness of a metallurgical plant. In the case of the Osprey Mine, the PAL-technology all ows a modification of the current preoxidation-ClPcircuit to two separate CIL-plants to treat run-of-mine ore and old tailings dumps. A doubling of the throughput is possible without enlargement of the plant. This innovation in the field of gold extraction, the combination of the PAL-process with a redesign of the metallurgical plant, can be considered as a basis for a more profitable gold mine.

Jan 1, 1991

By Hughson B

At present sane man-made Improvements and natural features are constraints on unlimited underground mining. 7 hey will continue to remain, as constraints on the future high production mining systems as wall. Unless these constraints are overacTe by research, where possible, future high production systems may became unacceptable. 7 he areas of future research include improved subsidence prediction techniques applicable to future mining systems, subsurface subsidence behaviour, mining systems capable of producing no surface subsidence and subsidence damage assessment.

Jan 1, 1988

By Arit I, Adisoma G

General Limit Equilibrium Method (GLE) and Janbu's Generalised Procedure of Slices (GPS) are two limit equilibrium methods in slope stability analysis which satisfy all equilibrium conditions. Numerical difficulties associated with these metho

Jan 1, 1998

By H Khoshrou, A Siamaki

Blast designs can have productive and non-productive impacts on downstream stages, mine productivity and operating costs. On the other hand, ground vibration, fragmentation, and back break caused by blasting impose damage and financial penalties and which must be controlled by blast design. One of the significant variables in blast design is the burden. In this study, the potentials of artificial neural network are investigated in prediction of burden in the Sungun copper open-pit mine. Input data were assembled through 18 blasting blocks according to different levels and experimental geomechanical investigation. To construct the model blastability index, uniaxial compression strength, hole diameter, specific weight of rock, rock quality designation and cohesion strength are taken as input parameters, whereas, burden is considered as an output parameter. Mean square error was used as the performance function and back propagation algorithm as the training function, containing four hidden layers and 14 data sets. Four sets of data were used to make sure that correct training had been carried out. This produced the coefficient correlation of 0.662.

Sep 26, 2011

By Jena, Anand S, Das R. P

Leaching studies were carried out on Indian Ocean manganese nodules using sulphuric acid as the lixiviant. By leaching the nodules with 8 per cent sulphuric acid for 12h at 100°C, copper and nickel could be completely extracted along with 50 per cent cobalt and 6.2 per cent manganese.94.2 per cent of the iron was also dissolved. To increase manganese and cobalt extraction, charcoal was used as a reductant. The role of charcoal was to reduce the manganese dioxide and render it soluble as manganese sulphate as well as to facilitate solution of the cobalt minerals associated with the manganese dioxide. Various leaching parameters were studied including acid concentration, amount of reductant, leach time, pulp density and leach temperature. It was found that by leaching the nodules with 10 per cent sulphuric acid at 100°C for 4h using 5 wt/wt per cent charcoal (0.05g of charcoal per g of nodule) almost complete extraction of copper, nickel, cobalt and manganese could be achieved. However, under these conditions all the iron present in the nodules was also leached.

Jan 1, 1989

By Motyka J, Adamczyk AF, Witczak S

A case study of migration of a paper factory fluid wastes, on the distance of 5 km from an underground disposal site to an ore mine is presented. The ore mine in question, situated in SW Poland is pumping 3.5 m3/s (ca 300 000 m3/day) of groundwater, producing a cone of depression about 150 m deep and several kilometers wide. The migration of wastes (pollutant) occurs within the carbonate karstic aquifer of Triassic age. The aquifer is about 100m thick and is characterized by the coefficient of hydraulic conductivity equal to 8 m/day on the average. The results of systematic measurements carried out for 13 years enabled to estimate the mean breakthrough curve of the pollutant. On this basis and taking into account the coefficient of hydraulic conductivity as well as the mean hydraulic gradient between the disposal site and the ore mine, the migration parameters of the polluting material, i.e. the real flow velocity, the effective porosity and the longitudinal disper- sivity have been calculated. As the measurements considered a long migration distance of the pollutant, the obtained hydrodynamic dispersion constant (dispersivity), in the authors opinion, is reliable enough to be applied for regional groundwater calculations, regardless of the "scale effect".

Jan 1, 1988

The objective in design of an excavation in a jointed rock mass is to achieve a prescribed degree of control of rock mass displacement around the excavation. Any excavation in jointed rock usually involves slip and separation along discontinuities as well as translation and ro- tation of constituent rock blocks. Thus, any acceptable model of behavior around an excava- tion must be capable of simulating the force displacement paths followed by the constituent elements, including rigid body translation and rotation. The distinct element method models such behavior by simulating the rock mass as an assemblage of rock blocks which interact through corner and edge contacts. Discontinuities are regarded as boundary interactions between blocks with joint behavior prescribed for these inter- actions. Introduction of structural element logic allows a variety of installed support sys- tems to be modeled. The response of the support to axial, transverse, and flexural loads is based on explicit algorithms similar to those used in the distinct element formulation. This allows large displacements and rotations and general non-linear constitutive behavior for both the support elements and the interface with the rock. This paper describes both the distinct element and structural element formulations and demonstrates several applications involving sup- port interaction with jointed rock.

Jan 1, 1987

Copper grades of diamond drill hole and development samples are determined in the core shed logging area at Mount Isa Mine using a Bulk Mineral Analyser. All geological and grade data on the copper orebodies is collected and stored on computer file.The raw data can be manipulated interactively using a computer terminal or by input of forms to produce output as computer plots or printouts. Grade distribution of copper or cobalt is obtained by the geologist using a computer kriging package followed by grade contouring. Computer plotted cross-sections and plans of individual stopes or several stopes can be produced showing geological structures, kriged grades at points and as grade contours.

Jan 1, 1985

By Tagawa H

In Japan, geological condition do not only vary in a wide range of strata but are also extremely complex with the existence of faults and aquifers. With respect to rocks, in particular, it is very rare that homogeneous rocks are distributed uniformly. In general, geological conditions are distributed in a wide variety, ranging from earth, sand, soft and medium rocks to hard rocks. Under these geological conditions, when planning of the tunnel construction is to be made out, either blasting method or tunnel boring machines must be selected taking into consideration the geological structures along with the designed tunnel route,' possibility of encountering aquifers, hardness of rocks anticipated and also, the adjacent environ- mental conditions. In the process of select- ing an excavation method,, it is important to make a comparative investigation between the above two methods considering the advantages and disadvantages with regard to the respective operating efficiency, economical efficiency and the conditions and scope of application as well. Furthermore, in addition to these considerations, the recent environmental restriction, which does not allow the blasting in the surroundings of residential areas, must also be taken into account. Because of this, in some cases there is no alternative but to use a static excavation method or a tunneling machine even when these are less efficient than blasting.

Jan 1, 1987

By Leach B. G

A geostatistical study was made of diamond drill hole intersections within 18CC stope block at the C.S.A. Mine, Cobar, N.S.W. The stope block is located in 18CC orebody which is a massive sulphide - multiple vein, Copper-Zinc type, lacking clear definition on gangue mineralogy, base-metal assays and total sulphide considerations. Of the variograms constructed for inter- section width and copper, lead and zinc grades and accumulations, only zinc displayed behaviour amenable to model fitting and kriging procedures. Zinc grades were calcu- lated for sub-blocks comprising the total stope block and comparison with equivalent grades determined by traditional methods showed them to be generally less extreme in the highest and lowest grade sub-blocks. The total-block grades derived by the two methods were almost the same. It is suggested that the failure of copper to show variogram continuity might reflect the difficulty in defining the actual 18CC orebody, a proposition which is supported by the poor continuity in the variogram of horizontal width. In the case of lead the poor continuity may be due to the frequent manner of occurrence of galena as coarse grained patches of limited extent. The results of the study, did not provide a convincing reason to depart from the traditi- onal methods of grade estimation at the C.S.A. Mine.

Jan 1, 1979

By E Asakpo, S Chaffer, A Heath

Newmont has had continuous production at their Ahafo operations, Ghana, since 2006. In 2013, Ahafo initiated an efficiency programme to improve mill performance and reduce energy consumption. Following this assessment, a Turbo Pulp Lifter (TPLTM) was installed in the Ahafo SAG mill in April 2015 to replace the existing radial pulp lifters. Plant operational data showed delivery of a power saving of 10 per cent, an improvement in throughput of 3.3 per cent, with no loss of grind size. Pulp lifter life was also doubled from 11 to 22 months.However, during subsequent relines when the grates were removed it was found that one in four of the outer pulp lifters were wearing at a faster rate than the remainder. This was investigated by Discrete Element Method (DEM) modelling, which predicted some overtopping and internal recycle within the pulp lifter. Significantly, the model predicted that the recycled material would pass back down every fourth outer pulp lifter, matching the field observations. Subsequently, the DEM investigation was continued and became an R&D project to improve the TPL design. The results are summarised here, leading to the development of the next generation Spiral TPLTM.CITATION:Heath, A, Chaffer, S and Asakpo, E, 2018. The development of optimised pulp lifter design for the Ahafo SAG mill using discrete element method modelling, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 585–594 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By J Brisebois

The derelict Lake George Mine is located at Captains Flat in NSW, acommunity of approximately 450, which lies some 43 km southeast ofQueanbeyan. It straddles the Molonglo River, which flows toQueanbeyan and thence the nationÆs capital, Canberra. Catastrophictailings dam failures in 1939 and again in 1943 resulted in the transportand dispersion of thousands of tonnes of sulfidic wastes downstream,with terminal settling in Lake Burley Griffin, in Canberra. The mine wasclosed in 1962, and major rehabilitation in 1996 - 1997 addressed the riskof further collapses, and reduced water flow into the underground mine.Nevertheless, acid mine drainage from the mine, and seepages ofcontaminated water from the capped tailings dumps continue to pollutethe Molonglo River for some 30 km downstream.Environmentally, the highest contributor to the total contaminant loadof the river is the Main Adit Spring. This was shown to be a constantgroundwater-driven acidic flow, with contaminant generation resultingalmost entirely from the ingress of gaseous oxygen into the undergroundworkings. Long term remediation may be possible at source, by pumpingreducing gases into the sealed mine, but the probability of thistechnology succeeding to the required degree is yet to be demonstrated. For at least the medium term, treatment of contaminated water flow(s)will be required to achieve any of the water quality targets that may beapplicable to the river. Three methodologies were short listed, but anumber of strategic uncertainties remain, which the NSW Derelict MinesProgram will address. Future risk arising from long-term contaminantrelease by the treatment wastes must be considered. Appropriate data,and realistic long-term performance parameters regarding the relativestabilities of water treatment sludges are scarce, and make properevaluation of competing technologies problematic.

Jan 1, 2003

This paper briefly discusses the negotia- tion of the more important provisions in agree- ments for exploration and mining rights with Pacific countries. LAND RIGHTS Land rights are complicated and sometimes controversial in many of the Pacific countries. In some countries, a company will have to deal with land owners directly; in others, the government will act as intermediary. Inevit- ably, a company will have to deal with both. Mining companies need to be sensitive to the culture and particular interests of the land owners and of their history in defending their rights. The issues are too complicated to be dealt with here. Some mining companies have spent, and will continue to spend, considerable time trying to understand them. It will " require patience, perseverance, sensitivity and unflagging optimism. The better advised companies will ensure that their local repre- sentatives get to know the land owners, under- stand their concerns, and will pursue a policy of keeping them informed on a regular basis of all of the company's activities and proposed activities. Good community relations are the keystone for good mining operations in the Pacific. Most countries will require the submission of an environmental impact statement so that they will know in advance what effects a pro- posted mining operation are expected to have on the environment and how it is intended to deal with them. They will also want to approve the company's environmental reclamation and rehabilitation plan. Let's face facts right away - mining, by its very nature, is not going to improve the environment. There will be waste discharges, emissions and deposits. They will affect the land, air and water and hence human, marine and animal life and vegetation. There will be sounds and odours and the esthetics of mining operations, though perhaps pleasing to geolo- gists and mining engineers, will not please Others.

Jan 1, 1987

By Nichol R

- PART A The Hoppers Crossing Pumping Station is one of the principal components of the Western Trunk Sewer Project which replaces the 90 year old Main Outfall Sewer and will convey 60% of Melbourne's sewage flow from Brooklyn to the Board's Farm at

Jan 1, 1987

The estimate of an ore reserve is a vital statement made about a mineral occurrence by an evaluator. It is important that such a statement communicate reality to all groups involved in a mining project, be they technical, financial, company directors, Stock Exchanges or the public. Ore reserve statements should state both resources and recoverable ore reserves. Resources may be important in very long term considerations, (because mining, metallurgical technology and economics change with time) but recoverable reserves are todays reality. The important factors contributing to recoverable reserves (in a general sense) are geology, mining method (and its impact on dilution and ore loss), metallurgical recovery, costs and commodity prices. These all need to be reflected in the ore reserve statement. In this paper recoverable ore reserve concepts across a wide range of orebodies are considered and discussed with respect to geology, mining method and ore reserve calculation procedures.

Jan 1, 1987

The winning and upgrading of mineral raw materials necessarily includes size reduction, which serves the liberation and production of marketable products from highly valuable and bulk materials. For crushing, the following factors can be duly accounted for depending on material type and the selection of the suitable machine: ò producing a particular size distribution, ò producing a particular grain shape, ò selective comminution, ò gentle comminution, and ò producing a size range required by a specific process and/or for a specific product.

Jan 1, 1993

By Hagen G, Uhlig H

In the Federal Republic of Germany the thermal environment in underground coal mines has deteriorated progressively over the past years. The number and capacity of refrigeration plants have increased correspondingly. In recent years high capacity spray coolers have been used in addition to conventional cooling coils.

Jan 1, 1988