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Rather like the mythical "Economic Man" "an employer" in this context must necessarily be an abstraction, and the views possessed by such an abstraction, a composite of many views known to have been expressed. Not even the complex Conciliation and Arbitration legislation in this country provides any helpful specifications, except in one peculiar particular. The Australian Conciliation and Arbitration Act provides an almost totally tautological definition, except in that one oddity referred to above. It is this : "An employer means any employer in any industry, and includes any person who is usually an employer in an industry, and also includes a Club." No doubt there is some perfectly justifiable reason for such specific and unique particularity in an otherwise meaning- less definition. That need not trouble us in this exercise.

Jan 1, 1982

By J Barnes

During September 2000, Nabalco management identified the need for a corporate system to deliver its key performance indicators (KPIs). In June 2001, a need was also identified to replace the existing metallurgical accounting system. After a review of the technologies available, the decision was made to develop the systems in-house, in preference to purchasing commercial software packages. This would allow much greater control over the structure, and provide for an iterative, concurrent development process between software and key business developers. This has proven invaluable in the development process. The purpose of the KPI system is to provide a unified reporting tool for all performance indicators. These indicators include production, safety, health and environment, personnel, costs, continuous improvement initiatives and opportunity losses. All of these disparate measurements are brought together into the KPI system and used to determine the performance for each department or area. The general principles of the balanced scorecard business approach (Kaplan and Norton, 1996) are applied to achieve a performance measurement for each area within Nabalco. The new metallurgical accounting system (MA) is a SQLServer database with web page and Excel interfaces. The database is structured around daily inputs of all measurements and calculations. The data is stored and adjustments and reconciliations can be made to this data as required. The focus is on accounting rigour, with all adjustments recorded in the database to allow for full auditing. The structure of the data focuses on the five input/output streams (bauxite in, caustic soda in, fuel oil in, residue out, and alumina out). In-circuit inventory provides a secondary measurement on which to check and calibrate the MA system. The KPI and MA systems were developed using Web technologies and are available to any internet-enabled device with Internet Explorer installed. This removes the need for software rollouts and user training. This will promote the wide use of the systems throughout Nabalco and Alcan.

Jan 1, 2002

Dartbrook (Hunter Valley and South Bulli (Southern Coalfield) Collieries provide contrasting settings for gas sorption studies. Gas compositions at Dartbrook are dominated by carbon dioxide, with minor methane, while those at South Bulli are dominated by methane with minor carbon dioxide. Total gas contents at Dartbrook are also significantly greater than those at South Bulli. The two collieries are also contrasted in terms of coal composition and mining environment. Dartbrook Colliery mines a relatively small sectionb(4m) of very thick seam (up to mapproximately25m); the coal is vitrinite-rich, high volatile bituminous. South Bulli mines most of the seam thickness, with coal being an intertinite-rich, medium volatile bituminous coal.Coal samples have been collected from in-seam gas drainage holes for evaluation of relative gas desorption rate (methane versus carbon dioxide). Following adsorption isotherms, petrography, chemistry (proximate and ultimate analysis) and pore structure analysis (carbon dioxide surface area, mercury porosimetry). Bomb desorption studies indicate different behaviours for methane desorption at these two collieries desorbed gas compositions at South Bulli show a small enrichment in methane content. The opposite is observed at Dartbrook. Both collieries show enrichment in CO2 in the residual content. Adsorption studies show marked variation in adsorbed gas contents for methane and carbon dioxide at each colliery and between collieries. These variations are related to differences in coal pore structure, chemistry and Petrology.

Jan 1, 1998

 Increasing concern about the impact of alluvial mining discharges on the water quality of some West Coast rivers lead to a joint West Coast Gold Miners Associate, Trade and Industry funded study by Water Technology (NZ) Ltd. The objective of the study was to assess the treatability of West Coast alluvial gold mining discharges and to develop simple treatment systems which could be effectively adapted to a variety of sites in the region.   The approach was to apply standard water treatment techniques to field situations using low cost technology. Initially the various types of alluvial gold mining operations were identified then after preliminary site investigations and laboratory studies were carried out, site pilot plants were set up. The results of the trials particularly those using chemical aids were encouraging and it was found that chemical aid performance was largely dependent on the degree of mixing at and downstream of the chemical addition point. Design alterations to settling pond configurations in conjunction with optimised chemical addition yielded dramatic results in the form of reduced effluent turbidities.   A generalised approach to effluent treatment was developed and some of the specific 'mix and match' requirements were identified for different types of sites. The general conclusion is that improved physical treatment combined with good plant management and operation and (where necessary) chemical treatment, will produce water of acceptable discharge quality.

Jan 1, 1989

By B Belle

In a deep, gassy predrained coalmine, ventilation and goaf drainage systems act as critical controls to manage longwall (LW) panel return gas levels. The goaf capture efficiency of most LW panels ranges from 45 to 85 per cent based on the gas domain at respective workings. Recent operational experiences have indicated that 50 m goaf hole spacing is optimal for management of high production retreat gassy LW panels, where the probability of goaf hole failures are frequent. Due to the horizontal stress direction geotechnical issues, goaf hole failure just behind the LW face is a recurring challenge resulting in significant and immediate increases in LW panel return gas levels. This paper presents a successful implementation of an innovative LW tailgate (TG) road cut through seal goaf fan/venturi system. The system incorporated a 17' (400 mm cased) hole drilled to 320 m deep in a perimeter roadway on a retreating LW TG road drawing the working seam horizon goaf gas behind the perimeter of seals. The surface goaf fan/venturi system was aimed to safely exhaust the LW deep goaf gas and thus withhold the goaf stream spillage to TG drive area and reduce the panel gas load by controlled operation of the system using continuous monitoring of CH4, CO and O2 levels. This control philosophy was made operational without impacting the use of the perimeter inbye ventilation shaft used for mine cooling and providing additional ventilation dilution capacity. The instantaneous reduction in TG gas levels of up to 0.3 per cent was observed even when the LW was 300 m away from the c/t seal goaf hole. Success of this concept TG seal goaf gas control system used even when the LW was 1300 m outbye has become an inventory of additional control for future deep and long LW blocks. This paper attempts to share the design process in addressing other risks and desired outcomes in managing the LW gas levels.CITATION:Belle, B, 2015. Innovative tailgate mobile goaf gas management in two gate road longwall panels – concept to implementation, in Proceedings The Australian Mine Ventilation Conference, pp 31–40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By K Li, C Zhang, i, J Oh, S Saydam, H L. Ram

Rock surface roughness plays an important role in excavation engineering projects and applications related to surface support structures, such as shotcrete and thin-sprayed liner (TSL). The morphology of the substrate affects the mechanical behaviour at the interface significantly. Therefore, it is necessary to quantify the roughness to investigate the relationship between roughness and mechanical properties. The joint roughness coefficient (JRC) proposed by Barton and Choubey (1977) is widely used in practice. It initially estimated the roughness by comparing it to 10 standard profiles visually. However, this method has lots of limitations, it is not only subjective but also a two-dimensional parameter with a small lab scale (Beer, 2002). The subsequent research on JRC, from visual comparison with Barton’s standard profiles to measuring the roughness with a profilometer (Weissbach, 1978; Alameda-Hernández et al, 2014). Then, 2D profiles or 3D surfaces by different technologies with higher resolution and accuracy, such as 3D laser or optical scanners (Fardin, 2004; Jiang, 2020, 2021). These 3D scanners are expensive and only suitable for laboratory scales. LiDAR scanners (Lato, 2009; Aubertin, 2022) have been applied in industrial size, but it is difficult to achieve a millimetre-level accuracy, which is mostly used to detect the thickness of shotcrete in practice. Thus, finding a cost-effective surface roughness measurement method with high accuracy is necessary. Photogrammetry is another method to digitalise the roughness of the surface. Similar to 3D scanners, photogrammetry also generates the point cloud of the objective surface and then reconstructs the 3D model of the objects. 3D reconstruction technology is a trendy technology in recent years. The structure from motion (SfM) algorithm (Westoby, 2012) to rebuild the 3D model with a flexible workflow, aligning photos, building dense point cloud, mesh and texture, which has been proved that can rebuild an accurate model in variable fields.

Nov 29, 2022

This paper deals with a few aspects of town planning and town management which affect human relationships within that town. Its scope is limited to the consideration of towns forming an adjunct to a mining operation, and particularly considers these aspects at the Hamersley Iron Pty. Limited, town of Parabur doo, Western Australia. Planning and standards of a new town and amenities are-discussed and related through living comfort to an effect on human relation- ships. Town administration and the promotion of many forms of social activities are dealt with in detail to illustrate the importance of quickly forming a cohesive community from a large number of newly arriving individuals. The results achieved by the planning and administration at Paraburdoo are highlighted by involving many residents by way of answers to a questionnaire.

Jan 1, 1973

By Sheng X. L

The Jurassic coals at Datong are characterised by their strong, massive sandstone and conglomerate roofs which fail suddenly over large areas, crushing pillars and creating destructive windblasts. collapsed areas have exceeded 180,000m2 and windblasts have extended over one km underground and 200m on the surface and have been accompanied by subsidence troughs on the surface. Scientific analysis has researched premonitory signs of caving and the nature of windblasts leading to considerations of alternative mining methods and ways of dissipating the energy of windblasts to reduce their damage and danger..

Jan 1, 1992

MOUNT STEWART is situated half a mile south of Leadville railway station, which is distant 240 miles by rail from Sydney via Mudgee. It forms a low ridge from which rock waste and alluvium slope gradually to the black-soil flats of the Coolaburragundy River. The Mt. Stewart mine comprises:(a) The Mt. Stewart workings in M.L. 44, parish Talbragar, Co. Bligh.(b) The Grosvenor workings in M.Ls. 44 and 45, parish Talbragar, Co. Bligh.(c) The Extended workings in M.L. 44, parish Talbragar, Co. Bligh.The workings contain 1375 ft.. of vertical shafts, 1105 ft. of underlay shafts, 800 ft. of rises and winzes, 8520 ft. of drives and crosscuts, and 18,000 ft. of stapes.The mine was first opened in 1888 as a silver-lead mine, and a waterjacketed furnace was erected during 18B2. The furnace was installed with two internally-fired tubular boilers of 35 h.p. and 25 h.p. respectively, and two Baker's rotary pressure blowers. The results of the smelting campaign indicate that, during 14 months, a total of 15,000 tons of ore were treated, yielding silver and lead. In addition to this, a quantity of matte was sold containing about 8000 oz. of silver. As a result of the treatment...

Jan 1, 1925

By A Mirzaghorbnali, D Gilbert, R Burton, J Nemcik, N Aziz

Glass-reinforced polymer bolts, commonly known as fibreglass dowels and fibre-reinforced polymer or plastic bolts or plastic dowels are increasingly applied for strata reinforcement in mines as well as in concrete reinforcement in civil engineering. The most popular dowels used in coalmines are the 22?mm diameter fully threaded type. Fibreglass and plastic bolts are cuttable, easy to handle, lightweight and corrosive resistant. A series of tests were undertaken to evaluate various strength properties of fibreglass dowels. These included tensile failure tests by the double-embedment method, a single guillotine shear test and a double shear test, carried out on dowels installed in concrete blocks, and with punch shear tests. Punch shear tests were used to evaluate the dowel shear strength parallel and perpendicular to the fibreglass strands or elements direction of extrusion. The study found that the tensile strength of the 22?mm diameter fibreglass dowels was in the order of 30?t. In the shear testing, the peak shear load was influenced by the encapsulation grout type and the level of fibreglass axial pretension. Also, there was a nearly fivefold difference in the shear strength value of fibreglass dowels tested parallel as against perpendicular to the dowel axis.CITATION:Aziz, N, Gilbert, D, Nemcik, J, Mirzaghorbnali, A and Burton, R, 2014. The strength properties of fibreglass and other polymer-based dowels for strata reinforcement in coalmines, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 263–268 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Most internationally traded iron ore resources are derived from multiple mine sites, transported to a port facility where they are blended and possibly further processed prior to shipping. Provided the proportion of contributions varies over a number of shipments an estimate can be made of the bias introduced by mine site sampling, analysis and materials handling systems, using zero-intercept multiple linear regression. Further regression applied to the residuals allows the error variances for the source mines to be estimated. Various sampling strategies are used by the industry. All have shipment-loading sampling on which payment or at least provisional payment is based. In most cases sampling prestockpile is used at mine sites to verify estimated production grades. Train grades are estimated from mine stockpile grades and in some cases train grades are verified by port input sampling. The methodology used is presented in this paper. Simulated data have been used and do not reflect the actual performance of any operator. The merits of the various systems and the implementation and potential limitations of our method are discussed more fully in a companion paper (Ziegelaar and Everett, 2010).

Mar 1, 2010

By Veal FL

Technological changes in Portland cement manufacturing during past years have reflected changes in the economics and availability of various types of fuel such as coal, fuel oil and natural gas. The industry consumes a sig- nificant quantity of both thermal and electric- al energy. The nature of the process and its chemical constraints does however permit the use of comparatively low grade fuels such as high ash coal and high sulphur oil. In striving for increased daily kiln outputs and conservation of energy, there is a worldwide trend towards the use of dry process plants. Wet process kilns of about 2 500 tonnes per day assume massive component sizes which present difficulties in manufacture, and transport to plant sites. Large capacity dry process units in excess of 8 000 tonnes per day are now in operation using precalcination techniques in which part of the fuel is introduced in the static preheater section ahead of the kiln while the balance is added to the kiln in a conventional manner. This technique has virtually doubled the potential output of any given single kiln.

Jan 1, 1976

By Langberg D, Gray N. B

The flocculation of hydrophobic magnetite with gold was examined as a possible means of recovering fine (95 per cent were possible for 1.5 - 3.0 ¦m and 5.5 - 7.5 pm gold sizes. The effect of process variables on the flocculation process was explained by variations in the adhesive force between the gold and magnetite.

Jan 1, 1991

By C J. R Hart, J K. Mortensen

The distribution of mineral deposits within northwestern North America (Alaska, Yukon, and northern British Columbia) allows for an in-depth examination of the metallogenic patterns of a growing continental margin. A more complete understanding of the tectonic evolution of this part of the Pacific Rim, achieved over the last 15 to 20 years, now allows for the placement of ore systems into a well-defined plate tectonic framework. Ore deposits older than about 185 Ma represent hydrothermal systems that were active in the platform/shelf environment of ancestral North AmericaÆs miogeocline or hydrothermal systems developed in oceanic arcs and continental fragments more distal to the craton. These include important SEDEX, VMS, and pre-accretionary porphyry deposits. In contrast, most mineral deposits younger than about 185 Ma were formed within the growing Cordilleran orogen, as terranes were accreted to the continental margin during interactions between the North America and Pacific/Farallon/Kula plates. Such syn- to post-accretionary mineralised systems include many large lode gold and porphyry/skarn systems.

Jan 1, 1999

By Y Lin, B J. Seligmann, M Hassall, S Micklethwaite

For multi-site mining companies, checking the quality and consistency of the data recorded in risk registers is important for confirming how well mine safety management systems have been implemented. However, this task is complicated by the differences in scope of the site, their particular nature, the complexity of the operations and many other factors that can introduce nuances to the characteristics of the risk registers. We present here an application of a technique called Causal Network Topology Analysis for comparing the quality and consistency of risk registers. By quality we refer to, for example: - missing causal relationships between risks - location of missing controls - focus of risk treatment strategies: prevention versus mitigation controls. By consistency we refer to how causally interdependent are the risk events. There are often causal interactions between the lines of a risk register that mean that the likelihood and consequence scores that are applied to each risk event are not independent. We measure this degree of interactions by: - proportion of independent scenarios per register - efficiency of risk treatment strategy comparison. This approach can indicate quality and consistency differences between registers irrespective of the actual details of the site or operation. This occurs by comparing aspects of the structure of a causal network extracted from how the risk events, causes, controls and consequences causally interact. In this work we compare pairs of registers to demonstrate the approach.

Apr 16, 2024

By N Stockton

Some preliminary results on the secondary leaching of previously heap leached gold ore are presented. Alternative lixiviants for gold comprising chlorine, thiourea and thiosulphate were compared with cyanide using bottle roll tests. Chlorine was subsequently selected for column leaching tests. Column tests at 1.0, 0.1 and 0.01 gL-1 Cl2 at pH 2 were conducted. The results indicated that about 23 per cent of the gold was leached over 45 days using 1 gL-1 Cl2 at pH 2. The experiments conducted proved that the chlorine/chloride system has good potential for further extraction of gold and silver from the existing cyanide heap leach residues and a process for secondary leaching of gold has been proposed. Further testwork is recommended to extend conditions, sample types, and the duration of leaching period.

Jan 1, 2000

Underground mining of the ore below the West Lyell open cut commenced in 1972 with the 10 Series stopes above rail haulage level. The third lift of stoping (30 Series) com- menced this year, and access to the 40 Series stopes is being developed. The method uses transverse open stopes with subsequent mass blasting of the rib and crown pillars and consequently there is sub- sidence and caving of the old open cut area above.

Jan 1, 1982

By J G Bastias

It is sometimes necessary to resort to extremes in order to call attention to something that is pertinent to safety in mining. When some of the experts in occupational safety talk about this topic, they usually refer to a 'regulation' established by the Romans which stated that, due to the health hazards, usually death, no Romans but only slaves should work in mining. Since the time of the Roman Empire, a lot of ground has been covered in the field of mine safety. Nowadays, it can be said that occupational safety is being seriously addressed, with the result that the number of mining accidents has reduced dramatically, fatalities in this industry are less frequent, and the rate of accidents compared with other activities, such as construction or fanning, is low. This achievement has been possible initially through government legislation and by procedures established by the mining companies themselves. However, the dilemma for government is whether to regulate and if so, how much. It is pleasing to observe that most companies are establishing working procedures which conform with new government legislation, placing strong emphasis on the duty of care for mine employees. There will always be some regulatory aspects of legislation, and perhaps the best example of this is in the use of mine hoists where there are no international or Australian standards, and the regulations applied are of an empirical nature that err on the side of safety.

Jan 1, 1994

ALTHOUGH the mineral Stannite (Cu2S, FeS, SnS2 , also known as "bell 'metal" ore, tin pyrites, etc.) is found in various parts of the world, in only three iocalities has development proved it to exist in sufficient quantity to warrant the erection of treatment plants. Two of those mines are in New South Wales and one is an Tasmania. The writer will deal with the latter-the Conah mine, Zeehan, Tasmania, it being the most important and extensive occurrence so far worked. The Conah mine was first worked by a Tasmanian company for silver-Iead, and was fairly remunerative until the zone of secondary enrichment was passed through, when the lodes became too poor for further exploitation. During the time that the line was thus operated the stannite lode was discovered. It occurs in a graphitic slate, which, in common with the slates and spilites of the Zeehan field, is probably underlain by the stanniferous granite which outcrops two miles to the west. The Conah stannite lode is older than the galena lodes of the district, being faulted by one of the latter. Near the surface the lode was very rich.Shipments were sent out assaying 150 oz. of silver per ton, 20% copper, and 18% tin. An .apparently homogeneous sample of stannite, analyzed by the writer for the Tasmanian Geological survey, gave the following results:

Jan 1, 1915

By Johnson M, Gaudin A

With the advent of Computer aided mapping and surface modelling techniques Geologists and Engineers have had to become familiar with the capabilities and limitations of these systems to effectively use them. In this paper we will trace a short history of the rather rapid progress in this area. From this historical perspective we will make some observations and use these to guess at what the future holds. We hope that this paper will assist in clarifying the develop- ments in computer assisted mapping and modelling and promote thought on how these techniques may be best applied to the problems of the Mineral Industry.

Jan 1, 1983