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The industrial practice of separating finely' around valuable minerals from associ- ated gangue materials by froth flotation is well known. Despite the obvious importance of this industrial process, the predictive tools for plant engineering evaluation of flotation process variable changes are still in a developmental stage. Consider, for example, the situation where an operating engineer is faced with evaluating a change in an existing chemical reagent scheme, possibly based on batch laboratory data. When all is said and done, the engineer must still perform detailed physical testing of the proposed reagent change on the actual equipment in plant use to be confident even of the direc- tion of change of plant results, let alone the economic viability of the change. The theory behind chemical reagent behaviour in froth flotation has been studied extensively, e.g., (Aplan {1980}, Fuerstenau {1976}, Fuerstenau {1962}, and Somasundaran {1980}), and, certainly, important progress has been made. Unfortunately, the nature of the flotation process, with its complicated heterogeneous surface chemisty activity operating on highly variable and difficut to characterize ore surfaces, coupled with com- plex mass and momentum transfer phenomena, :;l riously compromises the plant scale predictive capability of theoretically based models.

Jan 1, 1978

By Brook W. H

The history of the reduction of iron from its ores is lost in antiquity. Archreologists state that man has practised it for over four thousand years. Until comparatively recent times charcoal was the principal reducing agent for making metallic iron from its various oxidised ores. Coke was first used by iron founders in England in 1619, and its use spread gradually throughout the civilised world from then onwards. Indeed, the destruction of forests to obtain the requisite charcoal made the iron founders, both in England and America, extremely unpopular, and this hampered the iron industry to a considerable extent, until coal provided the metallurgist with a new and better fuel--coke which is used by most pyro-metallurgists today. The transition from wood to coal products for iron smelting had a profound effect on the location of iron works. Particularly was this the case in America where, in the infancy of the industry, practically each of the early States had its own iron producers, but as coal and coke replaced charcoal, there came about a concentration of the iron and steel industry around the coking coal deposits, and so today there are huge steel plants clustered around the soft coal basins in Pennsylvania and Illinois.The development of the iron and steel industry in Australia, which is comparatively recent by world standards, has been cradled in the coal basins of New South Wales. The first steel works of any consequence in this country were built near Lithgow, close by the mines which produced the coal for coking.Incidentally, these works were rather unique in that the three essential materials for iron and steel manufacture-ore, coal, and limestone-were found virtually at the works' back door.When, in 1912, the location of the proposed steel works for The Broken Hill Pty. Co. Ltd. for smelting ore from Iron Knob in South Australia was considered, the site ultimately chosen was at Newcastle, almost on top of seams of satisfactory coking coal. One of the major factors which had determined the site of the steel works was the fact that, about 1912, three tons of coal were required to produce one ton of finished steel product, and the relative economics of ore and coal haulage were much in favour of bringing ore to the coal.

Jan 1, 1947

By H Esterhuizen, W Hartman

Rockfalls or significant deterioration of mine openings can have significant safety and financial impacts for mining operations. The failure of drives in underground mines sometimes highlight deficiencies in the mine risk management systems in detecting geotechnical hazards and to prevent events that can have significant impact. Consequences from these failures includes fatalities, injuries, loss of revenue, additional cost, and potentially a loss in Ore Reserves. Where the impacts are severe, it also affects families and communities linked to the operation. The assessment of underground excavations requires consideration of the full range and spectrum of geotechnical hazards, design aspects, ground support, layouts and sequences. Where the assessment of these are insufficient or incorrect, it can result in drive failures. Care must be taken that meeting production targets and personnel pressures do not result in a situation where production take preference over a proper risk-based assessment of the drives to be mined. The risk management approach is now widely accepted in the mining industry for the control and management of risks in underground mines. Codes of Practices (COP’s), Ground Control Management Plans (GCMP), Principal Hazard Management Plans (PHMP’s) and technical guidance documents has become the norm for describing the mines main hazards, risk levels and intimating controls for safe passage of vehicles and mine personnel. However, where there is a disconnect between these documents and what is actually being done at the mine site, the COP’s and/or Management Plans become ineffective (or vice versa). This disconnect may occur due to the actual content of these documents, a lack of resources, or a lack of understanding about the implementation. There is therefore a need for sites to have a documented and implemented risk-based approach for assessing underground mine development. This approach or system needs to identify all hazards and other factors affecting mine development stability early on in the design process, and outline the risk classification and controls required. This paper presents an amalgamation and modification of previous processes for a Geotechnical Risk Management System for Underground Mine Development. CITATION:Hartman, W and Esterhuizen, H, 2018. A geotechnical risk assessment tool for underground mine drives, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 235–253 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Thomas G. A

THE irregularity of the Mount Morgan (Queensland) ore body presents problems other than those only of mining. For irregularity of outline is coupled with irregularity of grade, and the ore varies so rapidly from profitable to non-profitable, and fromhighly siliceous to highly pyritic, that the task of estimating quantities and values of ore reserves is manifestly rendered a difficult one, while the actual disposal of the broken ore demands constant supervision.Four classes of ore are handled. The oxidized ore, cheaply mined and cheaply treated, is obtained by quarrying from the top of the mountain. Below the 315-ft. mine level (measured from the original summit) sulphide ore comes in, and this is divided into siliceous sulphide ore (too siliceous for economic smelting), sulphide ore suitable for smelting, and ore too poor either to be smelted or to be treated by wet process with the siliceous ore. It is with these three latter descriptions of ore that this paper principally deals.Although the output from many stopes in the mine may usually be presumed beforehand to be either smelting or wet-treatment ore, yet it is never safe to take this for granted, and constant assaying is necessary. At the same time the ore merges from one class into...

Jan 1, 1911

The initially cautious approach taken towards ground support and reinforcement at the Porgera Underground Gold Mine in the Highlands of Papua New Guinea has evolved rapidly in the two years since stoping commenced. The confidence to continue the evolution process has grown from an increasing knowledge of mining conditions as stoping has progressed, to the extent that reinforcement requirements have decreased by 50 to 75 per cent depending on local circumstances. Changes to mining practices have significantly assisted and influenced this process.Empirical observations of ground behaviour, assisted by a deliberately selective extensometer monitoring program, provided the stimulus for early changes to ground support and reinforcement practices. Further optimisation of the ground support and reinforcement effort is being pursued through an active monitoring, measuring and analysis program. Ultimately, situation rather than site specific design will ensure continuing high quality ground support and reinforcement installations. However, local structural and lithological factors will continue to become more critical as the optimum position is reached.

Jan 1, 1993

By J Finlay, P Betts, D Milton, H Williams

The aim of this paper is to present an innovative method to help delineate potential target volumes for haematite-goethite mineralisation as opposed to more magnetic ores. This is achieved through interpretation and modelling (2.5D and 3D inversions) of ground magnetics and gravity surveys over the Koolanooka South prospect in Western Australia. The targets are assumed to be dense and weakly magnetic and hosted within banded iron formation (BIF) horizons. Geophysical interpretation (2D map) was performed using a variety of processed magnetic and gravity images (Betts et al, 2007) to determine the distribution of lithologies, to understand the structural architecture and to map out any anomalous areas of excess density (possibly indicating goethite alteration). The created geological map is used to build geological cross-sections (geometrically consistent) that were modelled (in 2.5 D) against both potential field datasets. The crosssections are consequently used as the framework to build a 3D geological model. The model defines 3D volumes of rocks including several BIF horizons. The distribution of densities and magnetic susceptibilities of the BIFs is inverted within the GOCAD«-VPmg environment to reduce the misfit between the response of the model and the observed gravity and magnetics. By combining the results of both petrophysical property distribution it is possible to map out (using classical GIS type queries in 3D) volumes of higher density and lower magnetic susceptibility.

Jan 1, 2009

By Abraham B. K, Jensen B, Gillies A. D S

The aim of the research was to investigate the feasibility of using an impedance cell and ratio-transformer bridge to measure solids content in coal slurry pipelines. It appeared that this technique could be developed to measure variations in conductance which correlate with solids content. Successful implementation of the measurement technique would have a variety of applications in existing coal wash plants and the potential for automatic process control. A small pilot plant was designed for a feasibility study. This was a closed loop system in which the coal was uniformly dispersed in a tank with a variable speed agitator and then circulated through an external pipe returning to the top of the tank. The impedance cell was located near the end of the external pipe. Slurry concentrations were varied from clean tap water to 50 per cent solids by weight with the addition of weighed quantities of dry coal dust. Ratio-transformer bridge measurements showed that variations in individual observations were equivalent to measurement errors of about two per cent. These probably reflect variations in concentration of the mixture in the pipe. Data for increments in concentration of one per cent indicate that this is about the limit of resolution of the current system. The paper discusses the principles of operation of the impedance cell and measurement system. Results from the pilot study and proposed improvements in the impedance cell design are examined.

Jan 1, 1995

By R Grobler, D Burger, L Alberts

The current climate in the mining industry is allowing mining companies to further broaden their views and investigate technologies to improve the safety, efficiency and cost-effectiveness of their operations. Furthermore, underground mine environments will become more demanding for mining equipment and personnel as orebodies become deeper in weaker ground conditions with more extreme environmental conditions. Loading and hauling can represent significant components of the production cycle of an underground mine and automation of these activities can offer considerable benefits. Sandvik has accumulated a long history and experience in loading and hauling automation in underground mining. Since the late 1980s Sandvik has actively participated in several major research and development automation programs leading to the commencement of the development of an integrated system for semiautomated loading in 1999. Development work was later conducted to expand the capabilities of the system for automated hauling during 2001 and the AutoMine« system became commercially available. The first delivery of the AutoMine« system was completed in August 2004 in South America, where the system continues to operate in a full-scale production environment and is being expanded as the production area enlarges. Further systems have been delivered and are operational in North America, Africa and Europe. This paper focuses on the AutoMine« system deployed in Block 4 at De Beers Finsch Mine in South Africa. An overview of the mine and the process used to acquire the system and the key drivers which led to the selection of an automated solution are described. An overview of the initial system installation, subsequent expansions and future plans are presented. This is followed by a summary of the implementation and operational experiences associated with automated underground operations. The paper concludes by summarising the benefits that have been realised.

Jan 1, 2008

By Cocker A

Pre-splitting for smooth highwall formation is conducted in around 75 per cent of surface coal operations within Australia. The CMTE (Centre for Mining Technology and Equipment) in conjunction with BHPAC (BHP Australia Coal) initiated a project to look at pre-splitting and to investigate the notching of blastholes for fracture plane control. The notching was specifically for pre-split initiation and also for discing of the toe of the production holes to minimise coal loss from the top of the coal seam. There are currently a number of factors which are driving the introduction of new pre-splitting technologies and products. The first is the ever increasing bench height being employed in strip mines which require a higher quality wall with less blast damage to maintain stability. Currently depths of 55 metres are common place with depths of 70 - 80 metres fast approaching. The second factor is the introduction of new technologies or methods which require a high quality highwall produced, eg highwall mining. This paper discusses the current state-of-the-art in pre-splitting and the main issues facing successful pre-splitting in the future. The use of a blasthole notching technology to promote fracturing along the pre-split line is also analysed. The review indicates that most pre-splitting challenges in the future can be addressed through better use and developments of current drill and blast technology. It is also concluded that a blasthole notching technique may find niche applications in improving final walls within a surface coal mine, especially where a high quality wall is required. The notched blasthole method may also allow pre-splitting in ground conditions and adverse rock structure which currently cannot be pre-split by existing technology.

Jan 1, 1995

An underground storage and filling distribution system is presently being established at North Broken Hill Limited in the No.3 Shaft area. This has been necessitat- ed by the dependence of the present filling system on the No.2 Shaft and its imminent closure due to cessation of production. The storage will consist of three tanks excavated in low grade ore, between the No.20 and No.21 levels, at approximately 2700 feet below the surface. The tanks will each have a capacity of 1500 cu yds. Consideration was given for surface storage, although under- ground storage was thought to have greater merits. Two tanks have been excavated, and are in operation. Three or more outlets are installed beneath each tank, with horizontal connections into the No.21 level 'mixing box'. Water decants from the top of the fill in the tanks, and passes into a decant water sump, at the bottom of which is a borehole to the No.21 level. This is then connected to the mixing box and water used as make-up water with the semiwet solids for transport into the existing pipe distribution system. Preliminary results of the system have been satisfactory and it is envisaged that this system will readily cope with the filling demands of the future.

Jan 1, 1973

By D Craw

Otago Schist and Klondike Schist are two Paleozoic-Mesozoic metamorphic belts on the circum-Pacific margin in which there has been a long history of abundant alluvial gold mining, but only minor hard-rock gold mining.   Modern exploration for hard-rock gold is ongoing in both belts, and the active Macraes mine in Otago (>2 Moz production) highlights the hard-rock potential of the geological setting of these belts. Hard-rock gold mineralisation in both belts formed in the latter stages of schist exhumation, after rocks were subjected to major regional ductile folding and then uplifted through the brittle-ductile transition. The majority of known hard-rock gold-bearing systems in both belts consist of well-defined, but generally discontinuous, vein swarms. Most Otago veins are hosted in steeply dipping post-metamorphic normal faults and fractures. However, the Macraes mine is hosted by a late-metamorphic shear zone, and much ore is sulphide-impregnated auriferous schist. Goldbearing veins in the Klondike schist are hosted primarily in extensional sites associated with post-metamorphic compressional structures. Some disseminated sulphide mineralisation is associated with Klondike veins and this is important as it extends the exploration target for these veins. No foliation-parallel late metamorphic mineralisation has been identified in the Klondike but exposure is relatively poor compared with Otago and both schist belts are highly prospective for deposits of this type.

Jan 1, 2007

The Quiruvilca district, located 80 km east of Trujillo in north central Peru (Fig. 1), has produced over eight million tons of Cu-Pb- Zn-Ag ore from approximately 60 veins since 1789. "Quiruvilca means "sacred tooth" in Quechua, the lingua franca of the Incas. The expression refers to a prominent volcanic neck exposed several kilometers northeast of the district. The district covers an area of approx- imately 24 km2. The mines occupy the eastern quarter; workings underlie 6.7 km2 with a developed vertical range of 280 m. All pres- ently operating workings are owned by Corpora- cion Minera Nor Peru S.A., a subsidiary of ASARCO Incorporated. The oldest rocks in the area are Lower Cretaceous clastic sedimentary rocks exposed 7 km to the east. Lithologies include sand- stone, siltstone, shale, coal seams, and carbonates (Cossio, 1964). These rocks were folded and affected by regional low-grade metamorphism during the early Tertiary, 40-65 m.y. (Hollister, 1977).

Jan 1, 1987

The Bradford Process, Australian Patent No. 11253, has had considerable application in the treatment plants of Broken Hill mining companies, and is at present being used by the North Broken Hill Limited for the treatment of weathered slime accumulations.The "Mining and Scientific Press," of 28th September, 1918, describes the Bradford Process at Broken Hill, specially featuring its application to slime material at the Proprietary mine-the home of the process.The points then stressed for galena flotation were acidulated slime pulp (0.025 to 0.030% H2S04) at temperature 85° to 90° F. and suitable time contact, with 1.5 to 2 lb. of sodium hyposulphite (per ton on slime) to permit the released S02 to "wet" or depressthe blende mineral. Also 1.0 to 1.3 lb. of crude sulphur (per ton on slime) was burnt, to supply S02 for keeping the lead concentrate clean during flotation. Pulp density varied from 23 to 26% solids. Since 1918 the process has been simplified in its application.Acidity of circuit, temperature, and sodium hyposulphite have been dispensed with, and now the S02 is practically all obtained by burning crude sulphur. I The plant units now employed for control and absorption of S02 gas constitute the main advance made in process, and these, with other details, are fully explained in this paper.APPLICATION AT BROKEN HILL NORTHThe existing North Broken Hill Limited gravity mill commenced operations on 9th September, 1909.

Jan 1, 1929

The outlook for suppliers of energy to the expanding economies of the Pacific Basin region is essentially positive, but particularly for exporters of high quality steam coal. This paper argues that economic growth in the Pacific Basin region has exceeded world economic growth for some years and that this will continue to be the case for the next decade at least. It looks briefly at the link between economic growth and energy demand and at the relationship between energy demand and the demand for electricity.Changing preferences in fuel mix for electrical generation in the region are noted and tentative forecasts made about variations in this mix. The pros and cons of various forms of fuel used to generate electricity are considered from the point of view of the consumer.

Jan 1, 1990

By S Youds

The backfilling operation at Olympic Dam mine supports a 9.8 Mtpa underground Long Hole Open Stoping (LHOS) operation. It involves a combination of Cemented Aggregate Fill (CAF), surface rockfill and underground rockfill. The fill material is introduced from the surface via boreholes into the top of the stopes. Due to the deleterious effects of the dust and the thickness of the atmosphere in the stope it is not possible to view the filling process either at optical or infrared (IR) wavelengths. The need for a means to measure the filling process is driven by the placement of both rock and CAF fill in the stopes. The large volumes and high relative cost of CAF makes the minimisation of CAF fill a business priority. Incorrect filling can lead to the sterilisation of ore reserve. The use of millimeter wave radar to view through the haze to give real-time data on the relative positions of the different fill masses is being developed as an in-stope fill monitoring device. This paper reviews the salient points of the technology and its potential use in the backfilling operation at Olympic Dam. The broader potential of this technology for use in the mining industry by æseeingÆ through water and dust laden environments such as that found in stopes and ore passes is also discussed.

Jan 1, 2002

By R A. Eggleton and, P de Caritat, K M. Scott

The Portia Au and North Portia Cu-Au-Mo prospects are located on a magnetic structure called the Benagerie Ridge Magnetic Complex, comprising varying pyrite-bearing Proterozoic albitite, phyllite and carbonaceous phyllite. The prospects are covered by up to 75 m of Cainozoic sediments, which comprise from top down, surface soils, Quaternary sediments, the Miocene Namba Formation and the (Late-Oligocene?) Portia Unit.The Portia Unit is dominantly clay-rich with local sand-rich base and it fills palaeo-topographic lows and a palaeo-valley that incised into the weathered basement rock (saprolite). This sedimentary unit hosts the majority of the Au grains found at Portia, with additional Au grains also present in the underlying saprolite. The North Portia prospect comprises saprolite hosted Cu-Au-Mo, with elevated concentrations of As-Pb-V present in the northern part of the prospect. These two groups of elements are delineated using factor analysis, and are regarded as the pathfinder elements for the North Portia mineralisation.Secondary Cu minerals including covellite and native Cu are present in the lower saprolite, and are stable under reducing conditions in the saturated zone.In the upper saprolite (unsaturated), Cu, Au, As, Mo and Pb are associated with Fe-oxides, mainly goethite and hematite. Saprolite leached of Fe generally contains low pathfinder elements concentrations.

Jan 1, 2004

By Feilding C

Vitrinite of humic source (often designated as vitrinite A) is the maceral by which the rank of a coal ought to be determined. Therefore its recognition, and the precise identification of other vitrinites is essential. The majority of Australian petrologists are not differentiating between the vitrinite group macerals in maturation studies, the results of which have led to unexplained phenomena in coal characterisations and evaluation, such as 'reactive inertinites' and inaccurate predictions in petroleum source rock studies. The Callide coal has been chosen as a case study, with examples from other coals. The coal seams from the Callide Coal Measures show variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56 per cent, and a range of 05. - 0.7, implying a higher rank than the 0.49 per cent Ro total vitrinite reflectance recorded in previous publications. Vitrinite B is one of the most commonly-occurring macerals in the Callide coal. The lower-reflecting vitrinite B which forms bands, often several hundred microns in thickness, in TEM appears to be electron transparent lipid rich. Vitrinite B is interpreted to represent accumulations of leaves, and is believed to be a major source of hydrocarbons in Australian sedimentary basins. The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from the amber to light brown fluorescence of exinite and the presence of exsudatinite in cell cavities and cleats. However vitrinite B, the major potential source of oil, is seen under the microscope to be generating oil, thus placing this coal at the top of the oil window. Micrinite, the origin of which has been much debated, occurs as cell filling or infill of spaces between laminations in vitrinite B.

Jan 1, 1991

By Stanley I. M, Brett D, Dickson R

The Mt Lyell Mine, situated in Queenstown on the west coast of Tasmania, has a production history of more than 100 years. Previous mining activities have resulted in substantial modifications to environmental conditions at Mt Lyell and disposal of sulphidic waste rock across the lease has left a legacy of on-going environmental impacts including acid drainage (AD). In 1995 Copper Mines of Tasmania (CMT) was granted a mining lease Irons the Tasmanian State Government for redevelopment of Mt Lyell and indemnity from actions concerning pollution from previous occupation and use of leased land. The Environmental Management Plan (EMP) for the Mt Lyell redevelopment committed CMT to be responsible for waste rock dumps generated from their activities and to ensure that management is in-line with best practice environmental management principles. CMT commenced commercial production in December 1995 with sulphidic material from development of the underground Prince Lyell mine reporting to a single waste rock dump constructed according to a management plan developed in July 1995 and superseded by a management plan for extension in May 1997. The CMT waste rock dump currently has a total capacity of 220 000 m- and approximately 120 000 m3 of rock have been placed to-date. Material reporting to the dump is placed in a densely compacted state to a controlled surface profile. The dump is clay capped and a final revegetated soil layer placed on top. A rock pitched drain extends down to a wetland area in order to remove stormwater and minimise possible soil erosion on the revegetated sections. An integral part of the management plan for the waste rock dump involves characterisation of waste rock to identify geochemical rock types according to acid forming potential with provision for selective placement within the dump. High-risk materials are selectively placed and covered within the core of the waste rock dump, where possible, to control sulphide oxidation. Monitoring equipment has been installed in the waste rock dump by the Australian Nuclear Science and Technology Organisation (ANSTO) and an on-going monitoring program has been established to demonstrate the integrity of the dump cover as a barrier to the influx of atmospheric oxygen into the dump. The overall objectives of this program of work are to control the oxidation of sulphidic waste rock in the waste rock dump, minimise the risk of AD, prevent pollution of the aquatic environment and thereby demonstrate the integrity of the CMT waste rock dump management Strategy.

Jan 1, 1997

By Francis R. S, Campbell J. J

Aberfoyle's Hellyer Division has filtered very fine flotation concentrates using two different makes of pressure filter. At the Luina concentrator a Larox pressure filter was used to treat a combined Pb + Zn or bulk concentrate. At the Hellyer concentrator two Lasta pressure filters are being used to filter copper/silver, lead, zinc and bulk concentrates. Operating parameters and performance at both operations are described. In both concentrators it was found that correct cloth selection was critical and that cloth failures contributed significantly to downtime. Thorough preventative maintenance progammes were required to ensure adequate availability of both makes of filter.

Jan 1, 1989

In 1948, it became clear that the ventilation system of The Zinc Corporation Limited and New Broken Hill Consolidated Limited mines, would be inadequate for future operations. The,paper describes in detail the process of designing an entirely new ventilation system for a large underground mining operation. The system was based on a single new upcast airway to be located on the boundary of the two properties, which were to be ventilated in parallel as two separate ventilating districts.From calculations of resistance, and assessments of future air requirements, the duties of a new exhaust fan to be located on the collar of the upcast airway were specified as 700,000 cubic feet per minute at 2·6 in. w.g. total pressure for initial operation in 1953 increasing to a maximum of 900,000 c.f.m. at 3·6 in. w:g. total pressure ten years later. The economic size of the new airway was calculated from a consideration of the first thirty years operation of the system, and it was decided to provide a 20 ft. diameter concrete-lined shaft.The new system went into operation five years after the initial planning, and the effect of the difference between actual and predicted rates and distribution or production are discussed. The final result was entirely satisfactory.INTRODUCTIONThe first proposal for an investigation of The Zinc Corporation Limited-New Broken Hill Consolidated Limited ventilation system with a view to putting it on a proper technical basis was made in 1938. A new Main Shaft was then being sunk, and it was decided to postpone the enquiry until this had been completed to No. 14 Level, when operations would be temporarily suspended and the shaft commence to operate as a major airway. The investigation was completed early in 1940, when Z.C. Ltd. upcast fan was...

Jan 1, 1956