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By Thierry Bernard, Jean Marc Laboz

This paper explains why and how integration of EIS (Electronic Initiation System) with dedicated software tools can increase benefits to blasters and at the same time simplify the design of blast sequence

Jan 1, 2000

By R. E. Hummel, J. W. Koger

IT is generally accepted that the martensitic start temperature (Ms) can be determined by resistivity measurements and is that temperature where the resistivity vs temperature curve on cooling first deviates from a straight line.1-4 Both Titchener and ever' and pops5 have used resistivity measurements to follow the martensitic transformation in b1 Cu-Zn and ternary Cu-Zn-based b-phase alloys, respectively. Actually because of the nature of their measurements the temperature of minimum resistivity (M) was used by these authors to determine "Ms" . Also, due to experimental difficulties in detecting M, with resistivity measurements, Pops and Massalski 8 determined M, by optical microscopy. The present communication is concerned with high-precision, low-temperature resistivity measurements which reveal a definite M, temperature which differs from the temperature of minimum resistivity (M). It is also shown that M is merely the result of the geometry of the percent-transformation curve and the temperature coefficient of resistivity of the alloy. In other words, it will be demonstrated that M has no apparent significance (except that it denotes a temperature at which some percent of martensite can be detected in a given alloy). Alloy specimens were made by melting 99.999 pct Cu and 99.9999 pct Zn in sealed and evacuated quartz tubes and homogenizing them at 601PC for 300 hr. After the alloy was cold-rolled into foils suitable for resistivity measurements, it was quenched in ice water from 871PC. The chemical analysis showed a zinc content of 38.8 wt pct. The cooling rate during the martensite transformation was 1°C per min and was controlled with a thermistor. Electrical resistivity measurements were made using a K-3 type potentiometer; the reproducibility of the resistivity values was better than 0.03 pct. Temperatures were measured with a thermocouple to an accuracy of better than 0.2° C. Fig. 1 shows the resistivity vs temperature curves of the martensitic transformation in B1 Cu-Zn for both cooling and heating. The starting point of the martensitic transformation (M,) was taken as that

Jan 1, 1968

By József Faitli, Barnabás Csoke, Károly Solymár, Zoltán Hatvani, Dimitri Papanastassiou

In most cases, the sizing of dry or wet mills for ore processing is primarily based on the determination of the Bond grindability index, using the Bond-Kjos-Rowland relations. In several cases, grinding takes place under conditions different from these and the grinding conditions have a great influence on the postgrinding process. This is particularly true for the grinding of bauxites where grinding takes place in alkali, often in higher temperature in alkali Liquor. So it is necessary to develop a testing method providing a reliable grindability index even under these special circumstances and allowing a more precise mill sizing. Therefore we surrounded the grinding crucible of the Hardgrove mill with a crucible furnace to heat it. The new heated mill is suitable to determine the grindability index under temperature-controlled circumstances, in liquids (water and alkali) with different temperatures. The required heating power is 2000 W. In the implemented equipment we installed four 230V/500W electric heating wires made from heat-resistant alloyed material and surrounded by ceramic insulators. The temperature and temperature-gradient are measured by four PT100 platinum thermal resistors. The data acquisition and control program written in the C language in the Lab Windows CVI program environment measures the voltage proportional to the temperature. Determining the grindability indices of hungarian and greek bauxites experimentally, first dry grinding tests were carried out under standard conditions. During wet and alkaline grinding, to 50 g of dry bauxite 85.5 g of industrial alkali with a concentration of about 200 g/l was added. As grinding aid 2 g of CaO (4 % of dry bauxite) was dosed. From the data it can be concluded: - The tested bauxites show a similar behaviour against temperature change. However, the extent of grindability change is different for different bauxites. - Soft Hungarian boehmitic bauxite can be ground in a high-temperature alkaline medium better than hard Greek one. The increase of grindability according to the high-temperature Hardgrove indices: (kHT = Dry o HT,alkaline H /H ): for hard Greek and soft Hungarian boehmitic bauxites: kHT = 1.7 and 2.4 respectively; according to estimated Bond indices (kB,HT =Wi,dry/Wi,HT, alkaline ): kB,HT = 1.6 and 2.1. - The increase of grindability is the most important factor the reaction of kaolinite with caustic liquor and lime and the loosing of the textural structure at 80 ºC and especially at 100 ºC.

Jan 1, 2003

By A G. Cuison, B V. Andam

Three well-known copper and gold deposits in northern Luzon, Philippines are located in the Mankayan Mineral District. These are the Lepanto Copper-Gold Deposit, the Far Southeast Porphyry Copper Deposit and the newly discovered Victoria Gold Deposit. The latter discovery led LCMC to shift from a predominantly copper mine to a gold mine. The pre-Eocene Lepanto basement andesite and the middle Miocene Balili volcaniclastic sequence underlie the Mankayan Mineral District. They are intruded by tonalitic to gabbroic Bagon Intrusive followed by diorite-quartz diorite intrusions. Diatreme emplacement of late Miocene-early Pliocene Imbanguila dacite pyroclastics and porphyries took place much later. Faults in the district mostly form a conjugate fracture pattern dominated by north and northwest trending shears, east-west trending extensional fractures and few north-south trending fissures. Victoria is an epithermal gold-base metal rich quartz vein deposit. The veins occur along tensional structures and it is common to observe crustiform and banded features among the sulphides and gangue minerals. It is an open space infilling type of mineralisation. The Victoria vein systems are divided into zones based on continuity. In each zone are major veins and associated spits. Dacite pyroclastics and porphyries predominantly host the major veins with a few narrow veins hosted by the Balili volcaniclastics and the Lepanto metavolcanics. The veins generally trend east-northeast with 75 - 80 dips towards the south. The longest vein can be traced fairly continuously for a horizontal distance of about 600 metres. The vertical persistence of major veins exposed on three level drives has a range of 150 metres and can reach as much as 400 metres based on drill hole intercepts. The vein widths vary from two to eight metres. Right lateral movements of either the NW or NE shear faults could have produced the east trending tensional fractures. The development of ore shoot patterns was recognised and has been helpful to the mining operations. Cymoid loops with defined pinch and swell features are noted both laterally and vertically. Complementing the structural pattern is the distribution of gold values along veins where lateral and vertical continuity is also observed. Gold is associated with quartz, sphalerite, galena and chalcopyrite. In relatively high gold zones, the abundant sulphides are sphalerite and galena. In relatively high copper zones, there is an abundance of chalcopyrite and tetrahedrite. Galena is always associated with sphalerite but less in abundance. Chalcopyrite occurs either as separate bands from or associated with sphalerite-galena. Chalcopyrite and tetrahedrite appears contemporaneous with sphalerite and galena but in some portions the former cuts the latter sulphides. The predominant gangue minerals are quartz, carbonates and gypsum. Rhodochrosite is the predominant carbonate gangue. Few sulphides are found in the carbonates. Gypsum (anhydrite) is found cross-cutting early mineralisation. It carries very few sulphides. The alteration halos around veins are relatively narrow. In an outward sequence, the silicic alteration occurs very near the veins, followed by sericitic-argillic alteration then to propylitic zones. It is also common to observe veins bounded by propylitic alteration. Preliminary paragenetic studies show apparent three stages of mineralisation, the early-quartz (-gold) stage followed by a carbonate stage and a late-gypsum stage. The abundance of base metals relatively decreases towards the gypsum stage. The Victoria gold deposit could have some genetic associations with the Lepanto Cu-Au deposit and probably indirectly with the FSE porphyry system. It is relatively apparent that the Victoria quartz-gold-base metal veins could have occurred similarly as the quartz-gold roots overprinting the Lepanto enargite mineralisation. This overprinting signifies the waning stages of the entire hydrothermal system.

Jan 1, 1999

Council for 2004/2005 President F.M.G. Egerton President-elect W.H. van Niekerk Vice-presidents Senior R.P.H. Willis Junior R.G.B. Pickering Immediate Past-president T.R. Stacey Honorary Treasurer J.A. Cruise

Jan 1, 2005

By J. L. Carr

Every year, severe injuries and fatalities occur when a miner is struck or pinned by a continuous mining machine, shuttle car, scoop or other piece of mobile mining equipment. Proximity detection systems offer a means to prevent these types of injuries and fatalities by sensing the presence of a miner and disabling machine motion. Although hundreds of these systems are installed and in use in operating coal mines, the influence that coal has on the electromagnetic fields associated with these systems has never been rigorously quantified. NIOSH researchers have conducted tests to measure whether the proximity of coal has a significant influence on a popular design of proximity detection system. The system tested utilizes a low frequency magnetic field generator that would be mounted on the mining machine. At the NIOSH Safety Research Coal Mine in Pittsburgh, researchers measured the performance of a simplified proximity detection system of this type first on the surface then underground at varying distances from a coal face. Analysis of these measurements shows that the presence of coal does not have a measurable impact. Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Reference to specific brand names does not imply endorsement by the National Institute for Occupational Safety and Health.

Feb 27, 2013

By Y Chen, G Xu, B Albijanic

High concentrations of airborne coal particles is the main reason leading to health and safety hazards in underground coalmines. Water spray is one of the effective methods to suppress coal particles in mine sites, but the use of plain water is not effective enough to capture coal particles. By adding surfactants, coal wettability can be improved which will increase the coal dust suppression efficiency. In this study, a modified sink test was employed to evaluate coal wettability in the presence of two anionic surfactants: sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS). Sink rates were calculated by measuring sink weight over test time. Different surfactant concentrations (0.01 per cent, 0.05 per cent, 0.1 per cent, 0.2 per cent and 0.4 per cent) and two types of water (tap water and deionised water) were selected to investigate coal wettability over three size ranges (0–38, 53–75 and 75–90 µm). The results show that both SDS and SDBS surfactants can lower the water surface tension and improve coal wetting performance. Sink rates increased as the surfactant concentration increased, and surfactant solutions prepared by tap water performed better than deionised water in enhancing coal wettability. Also, coal wettability varied for different coal particle sizes; the smaller coal particles were, the worse the wettability they possessed.CITATION:Chen, Y, Xu, G, Wang, R and Albijanic, B, 2017. Study on coal wettability for dust suppression in the presence of surfactants by sink test, in Proceedings Australian Mine Vent Conference 2017, pp 105–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By P. Anyon

Exposure to the microscopic particles in diesel engine exhaust can lead to serious health problems, including the incidence of cancers, heart disease and increased susceptibility to respiratory ailments such as pneumonia, bronchitis, and asthma. In Australia, mining companies and state government authorities are actively responding to this major occupational health and safety issue. Their initiatives place considerable emphasis on routine monitoring of diesel particle matter (DPM) exhaust emissions, both for engine benchmarking and as a part of routine engine maintenance. Implementation strategies follow two complementary paths: determination of individual engines? emission signatures combined with periodic engine re-certification; and co-operatively agreed industry-government engine maintenance programs, which are subject to audit. Both strategies place heavy reliance on real-time measurement of DPM concentrations in engine exhaust, using ruggedized instrumentation, mainly based on laser light scattering photometry. Adding value to this cooperative approach, industry has also collectively funded a government agency to design and manage a database, into which the results of all-routine DPM testing can be uploaded directly by individual mines. This win-win outcome is a great example of how cooperative action between governments and industry can deliver the goods: in this case, a safer working environment, more efficient energy use and the capacity to benchmark performance with industry peers.

Jan 1, 2009

By Yijun Caoa, Xiuxiang Taoc, Zhongbo Hub, Yinfei Liaoa

A new preparation scheme for a difficult-to-float coking coal from the Kailuan Mine, Tangshan, China was investigated. The results showed that grinding followed by column flotation was beneficial for obtaining products with low ash content. The positive effect of grinding on the coal floatability is attributed to the liberation of intergrowths and coal surface improvement. Tests indicated that 10 minutes was the optimum grinding time, and over grinding resulted in a deterioration in flotation performance. With a grinding time of 10 minutes, conventional flotation had potential to yield a product with around 12.42% ash content and 69.15% combustible recovery. Column flotation can reduce the product ash content to 11.15%and increase combustible recovery to 74.47%. Consistently better flotation results reveal that column flotation is more efficient than conventional flotation for such fines.

Jan 1, 2015

By G. S. Littlejohn

In anticipation of the flooding of an adjacent dolomitic groundwater compartment, five rough parallel sided boundary plugs at 58 and 50levels have been designed to resist safely hydrostatic heads of 1500and 1250 metres, respectively, over a service life of 100 years. Following a description of the engineering properties of the surrounding rocks, the paper details the design considerations relating to structural length and strength, hydraulic gradient, rock mass watertightness, constituent materials of mortar intruded concrete, pregrouting of permeable discontinuities within the surrounding rock mass, a bentonite barrier to resist aggressive mine water, plug tightening and design performance requirements. Routine quality control tests include permeability of the rock mass, fluidity, bleed and strength development of the intruded mortar, and temperature of the intruded concrete during curing. A special test programme includes determination of strength and stiffness of cored concrete and rock samples, shear strength of the rock/plug interface and associated in situ contact stress in order toe stimate the load safety factor against plug failure by shear.

Jan 1, 2006

By Peter Swanson, John Rettkowski

As part of a research program to reduce injuries and fatalities in the U.S. mining workforce, NIOSH is investigating the potential use of noncontact vibration measurements to identify hazardous ground fall conditions. In the present study, the effectiveness of remote vibration sources in exciting resonant responses in damaged structures is examined. Initial experiments were performed on a damaged concrete slab in a controlled environment. Vibration response was measured with a laser Doppler vibrometer using both single-point and two-dimensional array recordings. Excitation sources included direct mechanical impacts to remote portions of the slab and a remotely located industrial demolition hammer. Surficial damage was effectively delineated with both sources through visualization of vibration response in spectral bands selected to discriminate wave propagation from large-scale slab resonance effects.

The Southwest Pacific is a region of active volcanism and geothermal systems. Only in New Zealand have the geothermal systems been exploited for electricity generation and industrial processing. At present, approximately 280 MWe of geothermal electricity is generated in New Zealand. A considerable amount of further exploration work is required before the total geothermal potential of the region can be assessed and before the significance of these resources can be judged against other local energy sources.

Jan 1, 1990

By F. W. Schaller

TETRAGONALITY is an important aspect of the models of transformation, strengthening, and tempering of ferrous martensite. When the c/a

Jan 1, 1963

By L. J. Olivier

The possible closure and subsequent flooding of South Deep Gold Mine?s (SD) neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding SD. This paper describes the proposed controlled flooding of REL 4, the planned in-service monitoring of the five plugs and the water barrier between REL 4 and South Deep Mine, and the long-term maintenance of the plugs and rock mass in the immediate vicinity of the plugs.

Jan 1, 2006

By A. H. Larson, L. G. Twidwell

DURING the roasting of zinc sulfide concentrates and by-product recovery from flue dusts, the zinc sul-fate phase may occur in various stages of the processes. In addition to zinc sulfide, other sulfide phases are usually present such as CdS, PbS, CuzS, and FeS. Consequently, the effect of these sulfides on the thermal decomposition of ZnS04 was investigated. Merck high-purity, anhydrous zinc sulfate was used as the starting material. The sulfate was heated under an argon atmosphere, at a rate of 10°C per min. With the first slight indication of decomposition as determined by gas analysis, the sample was removed from the furnace and allowed to cool. X-ray patterns showed no other phase present. It is estimated that less than 0.05 pct of the ZnS04 decomposed. The metal sulfides were also heated under an argon atmosphere to drive off any adsorbed water. The materials were then sized (-200 to +270 mesh), mixed in predetermined mole ratios, and pressed into pellets. The experimental measurement of the reaction rate consisted of purifying the argon carrier gas, continuous flushing of the heated reacting mixture with argon, and collection and analysis of the SOn product gas. The reaction system was heated to 600°C and al-

Jan 1, 1967

By I. T. Oramah

Despite the abundance of solid mineral deposits, Nigeria only earns about 0.5-1% of its current Gross Domestic Product (GDP) from the solid minerals sector. This is as a result of the dominance of the oil and gas industry, which has negatively affected the competitiveness of other sectors of Nigeria’s economy. The dominance of this industry has resulted in unemployment, poverty, hunger, domestic price inflation, corruption, unstable government, and higher exchange rates. These impacts are typical for economies suffering from the effects of "Dutch Disease" and the "Resource Curse". Community-based small-scale mining offers hope as an economic activity that can create wealth, employment, reduce hunger and poverty, and provide basic amenities for rural communities with solid minerals endowment. This study presents preliminary results of ongoing research into the prospects of using community-based small-scale mining in a developing country like Nigeria to move towards rural sustainable development.

Jan 1, 2011

By Theo Lehner

Turning matte into anodes continues to be an area to watch: for visitors to see pyrometallurgy in action; for metallurgists to keep up with modern smelting furnaces and ever increasing production rates; for management to remain profitable using more tools than taught in school; and for environmentalists to detect the last small clouds from the ever cleaner smelter. Current converting practices have been screened and analyzed, and today, converting and casting is a modern industry. An impressive, though typical learning curve of converter productivity may be detected. Local conditions such as availability and type of raw materials, products extracted, cost factors, etc., have stimulated the development of add-ons or even alternatives to the still dominant method of converting by Peirce-Smith technology. Turning blister copper into anodes follows a similar path, namely increased productivity and improved quality. We dare to predict that development will continue.

Jan 1, 2005

By Doug Smith, Ross MacFarlane

"The Star Lake Mill was commissioned by Cameco (formerly Saskatchewan Mining Development Corporation) in 1986 to process a small high grade gold deposit in a remote location of Northern Saskatchewan. The lean approach to the 200 t. p. d. CIP mill to minimize capital and operating costs employs a number of unique features which are described along with highlights from the initial two years of operation.1.0 INTRODUCTIONThe Star Lake Mine is located 520 kilometers north of the City of Saskatoon (Fig. l) with the nearest population centre in La Ronge 130 km to the south. Gold showings were first discovered in the area in the 1940's with the Star Lake ""21 Zone"" ore body discovered in 1983. The Star Lake Mine started operations in 1986 becoming the first primary gold producer in Saskatchewan in over 40 years. The mine is operated by Cameco (formerly SMOC) with 50\ ownership in a joint venture with starrex Mining Corporation (35\) and Uranerz Exploration and Mining (15%).The limited reserves coupled with the remote location and the price of gold ($300-$350 u.s./oz) at the time the project feasibility was being assessed required a lean approach to make the short term operation successful. This paper describes the approach taken in the design and construction of the Star Lake Mill and describes the mill operation with highlights of the initial two years of operation."

Jan 1, 1989

By J. Jones-Parra, R. S. Reytor

The porosities of fractured limestone reservoirs can be divided into two broad types in accordance with their effects on fluid distribution and fluid flow. In the coarse porosity, gravity segregation lakes place freely and the resistance to fluid flow is very small. In the fine porosity there is no segregation and a high resistance to flow, and it has relative permeability characteristics similar to tight sandstones. By analyzing the affect of the two porosities it is concluded that in some cases to recover the maximum amount of oil it is necessary to remove large quantities of gas from the reservoir by producing at high gas-oil ratios. In this manner the fine porosity is drained of its oil and the gas-oil contact drops slowly permitting higher production rates from the oil leg. Since this conclusion is contrary to widely accepted principles of conservation, a mathematical model (Fig. I) was constructed to duplicate the conditions desired. The behavior of the model indicates that under certain conditions it is possible to recover more oil by producing at high gas-oil ratios than by production at low gas-oil ratios, and that the rate of production is affected more by gas shut-offs than by the decrease in pressure (Figs. 2, 3, 4 and 5). INTRODUCTION It has been noted that certain limestone reservoirs behave in such a way as to indicate that there are two distinct types of porous spaces available for fluid storage and fluid flow. Regardless of the nature of these porous spaces the distinguishing characteristic is that in one type of porous space there is definite gravity segregation between the oil and the gas; while in the other, the gas evolved tends to remain distributed equally throughout the reservoir. For the sake of simplicity the porosity in which gravity segregation takes place at a fast enough rate to affect the behavior will be called "coarse po- rosity", while that in which this is not so will be termed "fine porosity". The behavior of a reservoir of this type would be different than that of a sandstone reservoir, especially if most of the oil is in the fine porosity. It has been observed that fluid flow to the wells takes place mostly through the coarse porosity. The large fractures which

Though many mining and mineral processing companies have embraced the principles of sustainable development (SD), there is still a significant challenge of applying these in a practical sense, either in plant design or as part of day-to-day operations. The high-level nature of sustainability concepts often do not translate easily into workable activities or business case evaluations. This makes it difficult for engineers and company decision makers to understand whether their actions are making a contribution to sustainable development and a long-term business case. While several organisations have their own SD tools that can, to a degree, help identify these opportunities, they are largely ad-hoc and lack the necessary thoroughness to defensibly value these opportunities. Recognising these serious shortcomings, the Cooperative Research Centre for Sustainable Resource Processing (CSRP) has undertaken the development and trial applications of SUSOP« (SUStainable OPerations), a new concept that is somewhat analogous to HAZOP and the wider risk and safety frameworks used in projects today. The key goal of the SUSOP« research project is to produce a holistic, systematic and rigorous framework for project development, capturing, recording and evaluating SD opportunities and constraints against a chosen sustainability structure (eg Five Capitals). SUSOP« is being developed through an iterative process with input from research institutions and engineering companies. This integrated approach ensures that SUSOP«, in its final form, will have the academic rigour and industry realism required to assist the resource sector contribute to societal sustainability by embedding the concepts and processes into the design and operation of their assets in a meaningful and practical manner. SUSOP« has created much traction with both engineering companies and mining and minerals operators. This conference paper presents an overview of the SUSOP« framework and its current suite of processes as well as highlighting, through practical case studies, its capability to incorporate SD considerations at different phases of an engineering project's development.

Jun 1, 2010