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The word `environment' may have many different meanings but, for the purposes of this paper, I have assumed the definition included in the Environmental Protection Act 1986 (Western Australia). This Act defines `environment' as `... living things, their physical, biological and social surroundings, and interactions between all of these'. The Act further defines the `social surroundings of man' as `... his aesthetic, cultural, economic and social surroundings to the extent that those surroundings directly affect or are affected by his physical or biological surroundings'. This gives a very broad meaning to the idea of environment and environmental issues, and it is therefore understandable that the influence that environmental issues have on mining activity can vary so much from state to state, and even within states, and why the degree of influence can change so much with time.

Jan 1, 1990

By Hutchinson H

Froth flotation is applied to mineral sand concentrates in order to produce commercially viable xenotime concentrates. Experiments indicate that a xenotime product containing 38% Y203 at 47% recovery or 34% Y203 at 83% recovery can be obtained from a 27% Y203 feed. The process involves a primary stage of reverse flotation at which oxide and silicate gangue is floated, and secondary stage of direct flotation at which xenotime is floated. Of the various collectors screened an amphoteric compound was found to be effective at both stages. This was made possible by the addition of sodium silicate at the second stage, which acted as depressant for the remainder of the gangue. Similar studies on a low grade feed material were somewhat unsatisfactory as the grade achieved fell short of what was targeted.

Jan 1, 1990

Largely inherited from the past and from strictly internal laboratory use, the certification of reference material using round-robin assaying is often insufficient for the use made today for external assay laboratory control by client parties. Certification often needs to be revisited on the basis of existing round-robin data, especially to derive reproducibility parameters to the end of establishing probabilistic performance gates for operational error detection on a batch per batch basis (ie batch-ærejectionÆ). The most common difficulty arises when only a few certification samples have been analysed in one single batch by each laboratory, so that the round-robin data do not contain the full variability that needs to be quantified. Existing certification data sets from properly submitted round-robin samples were studied using analysis of variance to derive a remedial method, leading to the proposal of default correction factors to restore full variability estimates when no other avenue is available.

Jan 1, 2008

By P C. Pistorius

Previous mineralogical investigation of all effluent flotation streams of Mimosa mine (Zimbabwe) indicated that appreciable amounts of liberated platinum-group minerals (PGMs) of the Pt-Pd-Bi-Te class are not recovered û despite electrochemical measurements showing interaction between xanthate and such minerals. In this work, the flotation recovery of synthetically prepared Pd-Bi-Te was compared with that of chalcopyrite (a typical fast-floating mineral) and pyrrhotite (a typical slow-floating mineral), with microflotation tests. These indicated Pd-Bi-Te to be a fast-floater with flotation rates exceeding that of chalcopyrite. Predicted flotation rate constants (from the Ralston model) were significantly lower for small particles (with diameters similar to those lost to the effluent streams) compared with those of particle with intermediate sizes. This supports the suggestion that losses to effluent streams are caused by particle size effects.

Jan 1, 2005

An intensely sheared and mineralisedIzone occurs in the Quartz Dolerite Greenstone (or Younger Greenstone) mass on, the western limb of the Kalgoorlie Syncline. This zone comprises the western part of the Golden Mile and has produced the greater part of the 33,000,000 ounces of gold produced to date from the main mining belts. A study of.th e general geological and structural features gives rise to the expectation that the lode shear system,will continue southward on a pitch similar to that of the maln syncline whose axial plane may be referred to as the "Boulder Dyke". Although payable ore has recently been found further south than previously, the expectation of large quantities extending southward from the present mining areas is Problematical.'

Jan 1, 1964

The processes most likely to be adopted for beneficiating ores or concentrator streams containing a large proportion of particles finer than 10 um are froth flotation, selective flocculation, wet magnetic separation and selective leaching. Flotation will be made more efficient for very fine particles if ways can be found to selectively flocculate the valuable mineral beforehand (floc-flotation), to produce smaller bubbles and to reduce entrainment of ultrafine gangue. Schemes for selective flocculation have proved difficult to implement because of the delicate balance between surface forces (electrostatic, dispersion, hydrophobic) and hydrodynamic forces, that determines flocculation, and the changes which occur to particle surfaces through hydrolysis, oxidation-reduction and cross-contamination between minerals in aqueous suspensions. The search for a better understanding of selective adsorption of flotation collectors and flocculants continues and will be particularly important for the practical success of selective flocculation and selective magnetic coating.

Jan 1, 1986

By B J. Fallon

This study used structural equation modelling (SEM) to develop a series of models to explain the impact of work-life balance on employeesÆ perceptions of job performance, job satisfaction, turnover intentions and absenteeism. The sample comprised 257 participants (108 males and 149 females) from a range of occupations and levels of seniority. In sum, the results clearly demonstrated that successful work-life balance is associated with higher levels of job performance and worker satisfaction and with decreased levels of absenteeism and turnover intentions. The data also lent support to the impact of employeesÆ coping styles, schedule flexibility and supervisor support on employeesÆ abilities to balance work and life. It is concluded that tangible benefits to an employerÆs bottom-line can be anticipated from organisational initiatives to assist employees to better balance their work and personal lives.

Jan 1, 2005

By Restarick CJ

A compound cylinder-cyclone system, fitted with a flow control valve between the cylinder and cyclone, has been used for coal slurry sizing experiments in the range approximately 100 to 300 micrometres. An important feature of the system is the ability to adjust the cut size of the separation over wide limits by adjustment of the flow control valve. Results have been compared with typical fine screening operations. Under roughly equivalent conditions the compound cyclone system can achieve better elimination of extreme fines, but is not as sharp as the screen for coarser size cut-off. Simulations of systems involving combinations of the cylinder-cyclone system with screens indicate that the advantages of both sizing devices can be combined to yield accurately sized products for fine coal cleaning, at much less cost than using screens alone.

Jan 1, 1984

The mining industry has a well deserved reputation earned over the years for innovation, engineering, management and the quick application to mining of emerging technology. The cumulative result is the economic exploitation of lower grade resources. The developments during the last decade have done nothing to tarnish the reputation. There are many that come easily to mind: the use of contractors for both surface and underground operations, a trend toward mine management contracts, the increasing recognition of the economic potential of ground support, and the development of physical measures to achieve it, - sophisticated measures to analyse blasting , and thus improve fragmentation, - instrumentation to assist geotechnical appraisal, - the development and application of the powerful and flexible, excavator, - the evolution of measures to improve grade control, - massive improvements in equipment productivity and reliability built largely around the application of hydraulics, - the development of powerful computer packages for orebody modelling, mine design and extraction, - simple "dense" fill systems, - maintenance management techniques including the greater use of off-site maintenance of exchange components, - the utilisation of communication systems for data transfer.

Jan 1, 1989

In the past two decades the global metalliferous mineral industry has trended away from pyrometallurgical (pyromet) and towards hydrometallurgical (hydromet) technologies including biometallurgical (biomet) processes. Pyromet, biomet and hydromet technologies have all developed considerably over this period. New projects have been biased or directed by legislation towards supposedly cleaner and greener hydromet and biomet technologies. The environmental cost and energy cost of pyromet production processes for copper and cobalt are compared with comparable hydromet processes using Life Cycle Assessment (LCA). The æreal costÆ of the global warming obsession and negative public perception of pyrometallurgy include greater carbon dioxide emissions and energy consumption per unit, associated with current hydromet technologies. Specific examples for copper and cobalt produced via the different routes are provided. The poor science involved with the global warming hypothesis is discussed. The use of LCA with sensitivity analysis as a decision making tool for mineral processing projects and technology developers is discussed.

Jan 1, 2004

The beneficiation of heavy metal oxides, such as iron ore, is usually performed with heavy medium separation in cyclones, static baths and lately with Larcodems. Atomized ferrosilicon is most suitable as a heavy medium at densities above 3600 kg/m3 whereas a mixture of milled and atomized ferrosilicon is suitable at densities below 3600 kg/m3. When operating a beneficiation plant at densities higher than 3600 kg/m3 the quality of the ferrosilicon particles is an important factor that influences the control of the beneficiation process. Therefore, it is important to know how the rheology would be affected by the ferrosilicon quality as it also influences the control of the process at these elevated densities.

Jan 1, 2002

The ER&S Company operates a copper sinter plant, blast furnace and converter smelting complex at Port Kembla. Eighty percent of the smelter feed is dirty copper concentrates that contain some lead and zinc. The remaining twenty percent of the smelter feed is copper bearing secondary materials, some of which contain lead, zinc and tin. A predominately lead/zinc fume is produced during the smelting and converting of this feed mix. The composition and tonnage of fume produced at Port Kembla has varied over the years as the smelter feed sources have changed. The economic processing of the fume has always been dependent on the value of the metals contained in the fume and on the fume composition. Both pyrometallurgical and hydrometallurgical methods have been used to treat the fume for the recovery of some or all of the following metals - lead, zinc, tin, copper, cadmium, silver and bismuth. A detailed description of the treatment methods that have been investigated and used to process ER&S fume is given.

Jan 1, 1984

By S H. Marshall, H Hutcheson

Conventional batch cell and FASTFLOT pilot plant studies of reverse flotation of coarse marcasite and pyrite (100 - 400 μm) to reduce the sulphidic sulphur content of a rutile concentrate, were undertaken. The batch cell experiments found no significant improvement in sulphur removal with acid wash and copper activation of marcasite and pyrite. Batch cell trials also identified potential difficulties of conventional mechanical cell plants operated at 40 per cent w/w solids. The FASTFLOT 250 B-2 pilot plant trials indicated that with a 0.6 - 0.7 per cent w/w feed sulphur content, target product grade can be met on a routine basis by a three-stage FASTFLOT plant floating coarse marcasite and pyrite. The trials found that 150 g/t PAX dosage and 15 minutes conditioning time are adequate reagentisation for 40 per cent w/w solids feed to the FASTFLOT plant.

Jan 1, 1998

By Bilbrey J. H

Land utitized duxting the past 45 yeans by the mining industty in the United States con all puxpos ez to tal4 neatly 4 million sexes. Ob this axes, 13 pexeent is used bon dL4posal ob bLne -sized mtinexal wastes dL4eaxded by one milling plants. These wastes, especi- ally the inactive taLeLng4 ponds, xequixe some type ob stabULzation to pxevent aix and watex pollution. Because these tailings ponds axe locat- ed undex wideey vaxyting etLmctLe conditions and thetix physical and chemi- cal ehaxactexti5tLes axe not constant, many methods have been developed by the Fedexal Buxeau ob Mines and oXhex inve4- ttigatoxs box 4tabLtLzLng taLtLngs. This papex detfnea.e4 the magnitude ob the pxoblemz associated with the xeelametLon ob milling plant wastes and discusses the vaxtious methods that have been developed and used. Data bxom selected Buxeau o4 Mines taboxato&y xeseaxch pxojects and a s.abAJLzetLon field txtial axe pxesen.ed.

Jan 1, 1976

By E House, V Lisitsin

Recent whole-rock geochemical data from nearly 900 fresh drill core and underground samples taken from seven central Victorian gold deposits confirm the presence of distinct and identifiable primary alteration haloes surrounding the deposits. Ferroan carbonate alteration extends for up to several hundred metres away from turbidite-hosted gold mineralisation outside of contact metamorphic aureoles. A less distinct phyllic alteration zone can be identified using geochemical molar ratios or short wave infrared analysis. It generally overlaps a sulfidic halo characterised by disseminated pyrite and in close proximity to mineralised structures, arsenopyrite. The extent of the sulfidic halo can be traced using low-level analysis of pathfinder elements such as S, Au, As and Sb. Recognition of these alteration features enlarges the target for exploration and provides a tool by which drilling can be directed towards mineralised structures. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

This paper reviews an analytical model that defines the relationship of weight-weighted or volume-weighted average haulage distance with bench height and other related parameters; presents the optimum bench heights under various conditions in terms of minimising the weighted average haulage distance of ore/waste during the full lifetime of an open pit mine, and discusses the truck-haulage economics of mining open pits by high bench, specifically by 15 m, 18 m and 20 m bench through marginal analysis. The observations from these analyses disprove the previous conflicting assertions that the overall weighted average haulage distance either increases or decreases monotonically with bench height. It is concluded that: (i) an increase of bench height to 15 m from 12 m is likely to be viable under the general conditions of large-scale deep open-pit mines; (ii) the reduction of haulage cost is limited with the case of increasing bench height to 18 m from 15 m; and (iii) the feasibility of mining open pits by 20 m benches is generally questionable. These conclusions may serve as a useful guide for those who advocate open pit mining by high benches.

Jan 1, 1995

By J Kinal

Plant trials are at the best of times difficult to perform; given variations in the ore, operating practice and economic constraints placed on a plant. Testing grinding media at industrial scale adds a further level of complexity that needs to be accounted for.Laboratory test programs consistently demonstrate that altering the grinding chemistry through the application of inert grinding media has the potential to provide significant metallurgical benefit. However, prog- ressing from laboratory testing to industrial trial is often an agonisingly slow process that can lead to inconclusive results which raise more questions than give answers. There are many factors that need to be considered when conducting plant trials aimed at demonstrating the impact of inert grinding media on metallurgical performance. The decisions (or lack thereof) made during the planning stage can heavily impact on whether a statistically meaningful result is achieved. Various factors such as how the trial is conducted (dumping or purging the charge); the circuit configuration; collection of the right data; and even the human factor will affect the outcome. The authors will use examples to demonstrate the importance of proper planning and controlled operation on grinding media plant trials.

Jan 1, 2009

By Davey CJ

An integrated computer software system has been developed by Fluor Australia for modelling, mine planning and production scheduling of single or multi-strata deposits. Modelling of both quantitative and qualitative variables (e.g., thickness, basal elevation, density, grade/ash content) is performed via continuous, minimum curvature surface representations. These may be developed from inverse distance weighting or geostatistical kriging interpolation techniques in conjunction with bicubic spline surface interpolation. The modelling process, rather than being purely mathematical, incorporates facilities for reflecting structural geology interpretations (e.g., faulting, pinchouts) and geological boundary conditions (e.g., subcrop and outcrop). Volumetric programs provide the facility for continuous integration over models (at any specified integration increment) for any number of specified irregular polygonal panel areas or regular rectilinearly defined block plan areas. Multi-variable integration is available, incorporating any or all operations of addition, subtraction, multiplication and division to provide multi-strata tonnages, etc., (e.g., Volume 1 * density 1 + Volume 2 density 2). These programs provide true three-dimensional integration with the facility for calculating results on an area by area, level by level, strata by strata as well as overall basis.

Jan 1, 1983

By R Lastra

Applied mineralogy involves conducting investigations on ores, minerals and materials to solve problems encountered in mining, metallurgy, processing, industrial minerals, environment, health and other fields. The investigations are performed to determine the mineral behaviours during processing by using every mineral and ore characterisation technique and appropriate instruments. As the field is young, new techniques and instruments are still being developed. This paper attempts to convey the scope of the field by:describing the capabilities of the respective research instruments for determining mineral characteristics, summarising investigations of gold as an example of applied mineralogy studies of precious metals, andpresenting a case history where applied mineralogists worked closely with mineral processing engineers on a base metal ore and mill products to help the engineers optimise their processes for maximum recoveries.

Jan 1, 2008

By Parker C. J, Mikula P. A

The excavation for the Sydney Opera House Parking Station comprises a large donut shaped underground cavern with a central sandstone pillar. The maximum effective roof span is about 19 m and the rock cover is between 7 m and 8 m. Permanent support for the roof and the various services tunnels consists of a combination of tensioned anchors, and untensioned dowels, and mesh with shortcrete and fibrecrete as the final lining. Steel sets were installed at main intersections.Fundamental to the design philosophy for excavation of these spans at such shallow rock cover was the use of monitoring to check on the adequacy of the installed support. Prior to excavation, extensometers, inclinometers, piezometers and surface settlement survey stations were installed. Underground survey stations, anchor load cells and shotcrete pressure cells were installed as excavation proceeded. Excavation commenced at the crown using an initial heading and three widening stages. Geological mapping during excavation confirmed borehole expectations, namely sandstone beds 1 to 4 m thick interbedded with thin shale units. Bedding plane contacts varied over short distances from tight partings to thick brecciated seams. Jointing was subvertical and joints tended to be bed-limited.

Jan 1, 1993