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By M Hassall, E Humphries

Personal risk assessment processes, also known as Take 5 or SLAM (Stop, Look, Assess, Manage) have been utilised in high hazard industries for over 30 years. However, there is limited research to understand if a personal risk assessment process improves safety and health outcomes. The author’s learnings during discussions with training participants in G3/G-MIRM (Risk Management Systems) and G2 (Risk Assessment for Supervisors) courses have provided them with significant insight into understanding if a personal risk assessment process is valued across a number of mining industry organisations. These discussions arise when the four-layer model is presented (Figure 1) where ‘Layer 4’ represents the last resort risk checking activity. In this context, training participants agree that this process has value. However, the consistent opinion is that the personal risk assessment process is not effective, that it is a ‘tick and flick exercise’ and is not achieving the desired outcomes.

Apr 16, 2024

Operating metallurgists spend a significant part of their time running plant trials to compare two or more conditions in order to improve the process, such as a new reagent, flow sheet or piece of equipment. The best way to conduct such a trial is as a paired experiment when testing two conditions (eg 'old' and 'new') or a randomised block design when testing more than two conditions. These experimental designs should always be preferred over alternatives if their requirements can be met, because they block the effect of uncontrolled variables ('covariates') and are the most statistically efficient, ie they will lead to the required level of confidence in the outcome faster than other methods. Sometimes, however, it is not possible to switch condition easily, which is a prime requirement of these methods. In such cases the only option may be to switch condition once only, and compare the process performance before and after the switch. Examples are testing grinding media, large equipment, or long residence time processes such as leach trains or CCD thickeners. This paper considers some data analysis methods to deal with this situation. Modelling with intervention analysis (IA) uses regression models with a dummy variable to indicate the presence or absence of the test condition. IA with a time series model ensures that the residuals are uncorrelated. IA with a process model helps to deal with the problem of covariates. The reference distribution is a method free of any statistical assumptions but is less powerful than the other methods. Cusum charts are a helpful visual aid to interpreting time trends. A combination of these methods can help improve the confidence in the final decision. None are as good as a formal experimental design such as a paired trial.

Jan 1, 2008

Process engineering principles are used to analyse the features of leaching processes for large masses of low grade, unprocessed ore. Different performance characteristics are related to the numerous variants of these processes. The variant for which reagent enters a heap only via the input solution is further subdivided into three modes of operation. The three modes may occur in testwork and full-scale operations; the effects of process variables on the rate of the process are completely different in each mode. The mode can be identified by the time at which reagent first appears in the pregnant solution. It is related to the ratio of the height of the heap and the thickness of a band of ore in which the reactions are localised. Synthesis of the phenomena occurring within a heap via a computer program has produced a quantitative relation for the reaction band thickness. The program has been validated for several different systems. The overall achievement is that the mode of operation and the rate of the process can be forecast before column testwork is commenced. Some applications of the outcomes to testwork, process design and operational tactics are described.

Jan 1, 1994

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 J Mauk, J Rowland

The Karangahake epithermal Au-Ag mine consists of two main lodes, the Maria and the Welcome/Crown hosted in Miocene andesites. Mineralisation is strongly constrained to major structures and is genetically linked to dynamic tectonic processes. Two main periods of faulting are represented in the deposit: 1. NE striking right-lateral/normal oblique linked spatially and temporally with the mineralising system, and 2. ESE striking right-lateral/normal oblique post-mineral faulting that displaces the lodes. Paleostress analyses performed on a limited kinematic data set indicate NW-SE extension during the formation of the vein system. Veins and lodes strike NNNE and accordingly contain a strike-slip component. The kinematics of vein formation at Karangahake is broadly consistent with that of other deposits within a NNE-trending belt of deposits. Oblique shear on deflecting structures will create zones of compression and dilation. Dilatant zones created on steep structures create fluid pathways potentially focussing large volumes of fluid from deep parts of the system into dynamic structures.

Jan 1, 2003

AT Broken Hill, N.S.W., where flotation is tbe final stage in concentration, the gangue minerals are discharged as an aqueous pulp, and water recovery from the pulp being essential, provision must be made for the clisposal of the solids and for the return of the clear water to the cemcentrating mill circuit. This water also contains an appreciable quantity of flotation reagents, and is more effective for flotation than supply water.In the development of a scheme for the disposal of large quantities of residues, several of the more important factors for consideration are:(a) Tonnage to be handled.(b) Grain size of residues and pulp density.(c) Dewatering of residues and return of clear water to mill circuit.(d) Possible uses of residues.-A varying proportion of sand residues is used for underground filling, and to a limited extent for yoncrete making and other engineering work.(e) Choice of a suitable dumping area. - Before deciding upon this area consideration will be given to possible future operations so that the dump will not be likely to interfere with any development which may be necessary. Again, residues dumped at the present time as worthless or...

Jan 1, 1927

By P J. Harris, C T. OÆConnor

Collectors are used to impart hydrophobicity on particles thus increasing their chances of reporting to the froth phase. Also, the extent to which naturally hydrophobic gangue particles, such as talcaceous minerals, report to the froth can be reduced by the use of depressants. Thus the use of collectors and depressants will directly influence the extent to which hydrophobic particles report to the froth. However these hydrophobic particles will also have a direct effect on the characteristics of the froth phase, more strongly hydrophobic particles causing a reduction in the stability of the froth with the expected concomitant effects on grade and recovery. This study included microflotation (ie frothless flotation) and batch flotation of various ores using a number of different collectors and depressants and a newly developed froth imaging device (SmartfrothTM). Flotation performance was characterised by mass and water recovery, and recoveries and grades of the valuables. This paper shows how the various reagents influenced the behaviour of the pulp and froth phases. The critical importance of managing the type and dosage of reagents used in flotation with a view to optimising their influence on the froth phase is discussed.

Jan 1, 2005

By I Gipps

The mining industry has come through a period of major change in community expectations regarding safety and environmental impact and these changes can be expected to continue in the future. These changes are ultimately reflected in Government regulations and industry safety standards and form the basis of the ælicense to operateÆ. Equally, advances in technology have made possible new equipment and processes either available now, or close to completion, that will allow mines to meet these more stringent expectations if properly introduced. Changes in technology provide opportunities for mine management to introduce new systems that will remove people from hazardous areas and lead to improvements in the ætriple bottom lineÆ. In a longer time frame of five to ten years, novel and advanced technologies that are currently being developed will deliver new mining methods and conversion of presently uneconomic resources to ore. This is consistent with the time frame required to develop a new mine from discovery. Strategic decisions can be taken now by mine designers to enable the introduction of these major technology changes. Examples of both practical and strategic opportunities are drawn from the integration of rock cutting/blasting, automation, electronic communications and new mining methods. This paper discusses emerging industry trends, changes to legislative framework and some practical choices for existing and imminent technology.

Jan 1, 2003

Cobar Mines Pty. Limited (CMPL) uses sodium sulphite as the principal depressant to attain selectivity in copper flotation prior to sequential recovery of lead and zinc. The usage of sodium sulphite is examined both from a theorectical viewpoint ana from the manner in which the copper circuit at (MPL has developed. The results of relatively recent investigations, both in the laboratory ana the plant, are discussed aria shown to support the present operating Techniques.

Jan 1, 1983

Early theories of coal formation are outlined, with special emphasis on the arguments for allochthony and autochthony. Various aspects of the nature, growth, and decay of the characteristic vegetation of the brown coal peat moors, their conversion into coal, the origin of banding, and the influence of tectonics are discussed.A description of the banding in Victorian brown coals is followed by a discussion of their vitrain, fusain, and natural carbonized coal; and concludes with the nature of the coal resin and the possibilities of its extraction.The nature and derivation of inorganic matter in brown coal, based on Lessing's classification, is described. Assimilation of mineral substances in specific plants with variations due to environmental factorsare illustrated by analyses of present day trees. Consideration is then given to possible sources of salt, marcasite, and quartz in brown coal.It is shown that part of the inherent and extraneous ash may have been removed during and after coal formation. The nature and abundance of the organically combined substances in brown coal emphasizes the anomalies that may arise from estimating the total inorganic matter from ash contents.After classifying deposits on external heating surfaces of boilers, theoretical and practical aspects of slag formation, alkali matrix deposits, and the effect of sulphur and chlorine are considered.Analyses of deposits in boilers burning Victorian brown coal are tabulated.Slagging at the Yallourn power station from sand in the Yallourn open cut, and difficulties with Yallourn North Extension coal at the Maryvale paper mills are described.Tests carried out on Morwell and Yallourn coals showed that with the former, impacted deposits formed on boiler heating surfaces, and left a high percentage of chlorides on probes. Morwell briquettescompared with Yallourn briquettes also reduced the running time of a semi-industrial boiler through deposits with sodium sulphate as...

Jan 1, 1962

By K Tungpalan, E Wightman, M Edraki, E Manlapig, L Keeney

The depletion of easily mined high-grade ore bodies resulted in the industry having to exploit lower grade, complex resources (Albanese and McGagh, 2011; Darling, 2011; Randolph, 2011). The trend is now towards mining and processing of low-grade and complex ores (Darling, 2011; Yingling, 1990). Variable geological and mineralogical characteristics, and complex mineralogy and texture can result in large variations in metallurgical response and also cause challenges in processing. (Carson, 1995; Lorenzen and Barnard, 2011; Yingling, 1990). Variability and the complex nature of ores are fundamental sources of risk that often cause the greatest economic impact (Dusci et al., 2007; Williams and Richardson, 2004). Hence it is important to effectively characterise these types of ore bodies and assess their processing performance (ie recovery, grade). To enable this, there is a need for the following: (i) characterisation of geological, mineralogical and metallurgical variability in the ore body; (ii) effective selection of drill core with characteristics that represent the range of ores in the entire ore body. CITATION: Tungpalan, K, Manlapig, E, Keeney, L, Wightman, E and Edraki, M, 2018. A systematic approach of sample selection to predict processing performance of an ore body, in Proceedings Complex Orebodies Conference 2018, pp 67–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By Just GD, Gillies ADS

The competitive coal market has required coal producers to put more effort into coal quality control. Successful quality control requires a good estimation of the in situ coal quality as well as a good estimation of the probable fluctuation of the in situ coal quality during production. Geostatistics offers a very promising way to meet this requirement. A geostatistical approach toward the coal quality control problem is presented. Two models, the prediction model and the conditional simulation model, have been developed for coal quality data from two large export coal mines in central Queensland, Australia. The mine planning and scheduling aspects based on this and other potential applications of the models are addressed.

Jan 1, 1990

By P Dean, M Elmouttie, Y Duan, X Luo

Slope instability is one of the major concerns in open pit mining operations. A significant collapse of the pit wall can result in injuries, damage to machinery and interruptions to production. A broadband microseismic monitoring technique has been developed for diagnosing the healthy condition of a target slope area. This technique has been successfully applied to an open pit mine in Chile. Our research has found that this microseismic monitoring technique can be used in open pits for tracking and locating a falling rock that is rolling on a slope, if a dedicated seismic sensor network has been established. In collaboration with other monitoring techniques (radar, laser scan, aerial photography), more accurate determination of rock rolling trajectories can be obtained. In this paper, an example of using the CSIRO microseismic monitoring technique at an open pit mine is presented. Results from an experiment where we used the microseismic technique for determination of the trajectory of a rockfalling on a slope are also presented.

Nov 8, 2021

By Seedsman R. W

Good roads are essential in moving men and materials to and from the underground workplace. Coffey Partners International Pty Ltd (Coffey) has recently completed a underground coal industry funded project on underground mine road construction and maintenance. This paper discusses practical approaches to construction and maintenance of underground mine roads using transferrable civil technologies and innovative techniques. Mine pavements are generally low-cost (relative to civil roads), constructed to varying standards using locally available materials to best meet the mobility needs of the mine. Performance of pavements is thus largely dependent on the environmental conditions, quality of the available road making materials, maintenance policies and available resources. The paper will detail `what causes bad roads?' in various underground environments, available management strategies, construction and water control techniques, road maintenance and vehicle considerations.

Jan 1, 1995

White Cliffs Opal Field is situated in the Parish of Kirk, County of YulguIgra, New South Wales, about sixty miles from Wilcannia, and the River Darling. It is near the southern edge of the cretaceous basin of the interior of Queensland, New South Wales, and South Australia. Twelve miles south-west of the field, at Tarella station, a well sunk at the homestead reached silurian slates at about 127 feet, getting no water but about three miles north-west from the originally discovered and no central portion of the field, a well was sunk by the Momba, Pastoral cmpany, to a depth of 270 feet all the way through the cretaceous beds. At 250 feet a small supply of water was struck, but so much mineralised as to be quite useless. The temperature also was so high that a man could not keep his hand in it and Mr. Hogarth, the Momba Pastoral Company's manager, informs me that so corrosive was the action of the water, that a shovel left down the well for a fortnight, at the time of sinking, was completely eaten away.The well having now fallen in, I have been unable to obtain any of the water for analysis.The western termination of this portion of the cretaceous basin is situated about twenty miles from the present opal field, at which distance the slates, with (probably) devonian sandstones and quartzites resting unconformably thereon, commence to appear. The opal bearing country, as far as at present known, follows a more or less well defined line running north and south towards the northern end of the field, and north-east and south-west towards the southern extremity.

By Zhou Y, Karmis M, Haycocks C

Hazard analysis utilizes interaction mecha- nisms in combination with geologic, structural and mining conditions to delineate areas of potential damage in seams subject to interaction. Using characterizations of conditions peculiar to multi- seam mining, such as innerburden thickness, geol- ogy and structures, initial interaction contour maps can be constructed. Geologic hazard analysis is then carried out on roof, pillar and floor condi- tions in the affected seam using lower seam rock properties and layout geometries in the overlying seam. Either safety factors or damage ratings can then be developed representing degree of hazard in the lower seam. The final hazard map shows both the aerial extent and magnitude of potential dam- age from interaction.

Jan 1, 1992

By Ralph AM, Deakin JJ

A quantitative knowledge of underground mine ventilation requirements and conditions has become increasingly important, both to meet statutory requirements and to ensure high levels of safety and productivity within mines. The ACIRL Mine Ventilation System MINVENT was designed to provide a flexible means of analysing the behaviour of an underground mine ventilation system under a variety of conditions. It is not sufficient to rely solely on the analytical tools such as ventilation network analysis computer programs - these must be supported by the expertise necessary to conduct an accurate underground ventilation survey as well as experience of typical conditions to be expected in the evaluation of proposed extensions to a new or existing mine. When planning a new mine, the ventilation engineer can use the program to draw on a set of typical ventilation parameters, seam and proposed mining methods. These have been assembled as a result of numerous ventilation surveys conducted by ACIRL in New South Wales and Queensland.

Jan 1, 1983

By D Craw

The Macraes gold deposit is located in a low angle NE dipping (~15¦) shear zone, the Hyde Macraes Shear Zone (HMSZ) cutting greenschist facies metasediments of the Otago Schist. The shear zone is host to large volumes of mineralised schist and relatively sparse quartz veins. Early in the development of this through going shear the schist experienced an episode of hydro fracturing and fluid redistribution. As a result, presently exposed schists within the Intrashear sequence are pervaded by localised swarms of quartz filled pure extension and extensional shear fractures hosting goldscheelite mineralization. The swarms comprise networks or æstockworksÆ of veins that strike NE, are subvertical and form subperpendicular to the shear zone fabric. Vein frequency across strike is typically ~1 m-1, with most veins five to ten centimetres thick and vertically continuous for up to ~20 m. Many of the veins show delicately banded internal textures that are parallel to the vein margins. These bands/lamina indicate incremental growth and are defined by a variation in grain size or alternatively by thin slivers of wallrock schist, though typically uncommon. The majority of veins are overprinted by a weak plastic deformation, although primary structures are largely preserved. This deformation has produced subgrain structures, migration of grain boundaries with sutured margins and undulose extinction of grains. These microstructural observations possibly indicate that temperatures were around 300¦C during stockwork vein formation. In general, the mode of brittle failure that developed the stockwork veins can be directly related to lithological variation. The geometry of stockwork veins indicate that local vertical shortening and extension occurred in the Intrashear sequence of the HMSZ synkinematically with thrusting. Localised extension was mainly parallel to the structural trend; that is, it took place perpendicular to the direction of inferred thrusting. The development of lateral ramps most likely gave rise to extension in parts of the shear zone during continuous shortening to form swarms of stockwork veins.

Jan 1, 2004

The metals titanium and zirconium and their alloys occupy individually unique positions in the catalogue of metallic materials available for engineering applications. Because of the uniqueness of their usage in the aerospace industry, in the case of titanium, and in the nuclear industry, in the case of zirconium, the except- ional resistance of both the metals to the majority of corrosive media is often overlooked. The cost factor in the application of these more exotic metals has, in the past, been a major considerat- ion in the rejection of titanium and zirconium as constructional materials in areas of usage where their superior corrosion resistance strongly favoured them over more conventional metals and alloys. The cost differential, vis-a-vis austenitic stainless steels, for example, is not a trifling matter, being of the order of 6 : 1, when compared on a weight basis. However, if one considers the cost, for, say, sheet product on an area basis, the ratio is redgced to approximately 3.4:1. If one also takes into account the enhanced performance of the more expensive material and the sub- sequent increase in service life and decrease in plant down-time, the economics of the usage of materials such as titanium becomes much more attractive and, indeed, highly competitive,

Jan 1, 1969

The paper examines the difficulties encountered by objectors to mining privilege applications. It describes the various involvements of the environmental defence society in the mining controversy and makes some comment on the proposed amendments to the Mining Act 1971.

Jan 1, 1981