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By Smith I. W

Australia has, and faces, a growing problem with regard to the ability to meet the demand for liquid fuels from indigenous petroleum resources. The position for natural gas is better but there is no room for complacency. Since the coal resources are relatively extensive, interest in the prospect of producing liquid fuels from coal is in- creasing. The approaches to the production of gaseous and liquid fuels are briefly reviewed and the present status of coal conversion technology is discussed. Many problems remain to be solved and it is estimated (in the USA) that another 8-10 years will be required before any of the processes for liquid fuel production are considered sufficiently efficient and viable to go to a demonstration plant. Coals represent complex feedstocks and the effects of variations in coal properties on oil-from-coal processes are not fully understood. The thermal efficiencies of various coal conversion processes are considered in relation to their impact on coal requirements. The production of Australia's present requirement for liquid fuels by the only commercial process in operation would require a four-fold expansion in the local consumption of coal. Any assessment of the suitability of oil-from-coal processes currently under development overseas for Austra- lian coals and requirements must take heed of the differences in coal properties and motivation. The economic via- bility of processes for producing oil from coal will continue to be uncertain because of the large difference between the World price for crude oil and the actual production cost.

Jan 1, 1975

By Williams RC

Overlying the coal deposits of the Sydney Basin are several lakes and other bodies of water. These include the Pacific Ocean, Lake Macquarie, the Tuggerah Lakes and the stored waters of the dams of the New South Wales Metropolitan Water Sewerage and Drainage Board. The coal beneath these bodies of water amounts to hundreds of millions of tons. Colliery workings have approached these areas of water and in some instances first 1"orkings of bord and pillar have taken place oi_eshh the water. he problem which now faces mine manage- and other interested authorities involves the determination of the maximum ;mount of coal which can be safely extracted from beneath the water. There are many factors to be considered including the depth of cover, seam thickness, geological details and strata movements.

Jan 1, 1972

The changing characteristics of raw materials has highlighted the limitations that conventional vibrating screens have in the handling of fine wet sticky materials. These' limitations have led to the development of a totally new concept of screening, the Rotating Probability Screen. In order to illustrate the practical benefits to be gained by the extraction of fine materials ahead of subse quent processes particularly in the coal industry, the experiences gained in Ro-Pro installations in America, Australia, Europe and Britain are drawn upon.

Jan 1, 1984

By J Williams

The recent drought has highlighted the finite nature of AustraliaÆs divertible water resources. According to AustraliaÆs recently completed National Land and Water Resources Audit, development of water resources in southern Australia has reached or exceeded sustainable extraction limits. Similarly, 161 out of 538 groundwater management units are either totally allocated or already over allocated. Whilst mining only uses about three per cent of diverted water resources, water scarcity may be a major factor that determines whether potential mines can be developed in the future. Furthermore, the development of extraction and processing facilities that limit water use and maximise the re-use the waste water streams will be even more fundamental features of the mining industry in the 21st century than they are at present. There are encouraging examples where innovative water re-use technologies are significantly reducing the water used per unit of mined product. Whilst mining in the areas of Australia draining to the tropical seas may be less constrained by a current lack of water (60 per cent of divertible water resources drain into the Timor Sea, Gulf of Carpentaria and north east Coral Sea), it is highly probable that there will be increasing demand for these waters from the irrigation industry, whilst pressure will also be applied to ensure that environmental flows that benefit the coastal fishing and prawn industries are maintained. In the Great Artesian Basin, current research is demonstrating that the groundwaters are being recharged at rates considerably lower than current extraction. Whilst some other groundwater basins in arid and semi-arid Australia have currently untapped resources, these water are often relatively saline and/or may be intimately linked with key ecosystems in discharge areas. This paper presents an overview of the current state of our water resources and examines some of the key water use issues including allocation, use and reuse, environmental flows and competing demands on the resource that will ensure that water issues remain high on the policy agenda for mining, irrigation and other water users.

Jan 1, 2003

The hydraulic backfilling of mine tailings has proven very successful at the Homestake Mine in Lead, South Dakota. It allows greater versatility, selectivity and safety in mining. It has also minimized surface subsidence and underground rock movement. The tight filling also eliminates underground fires. This paper explains the hydraulic backfill method used and the problems encountered by so doing.

Jan 1, 1973

A series of numerical experiments were performed in order to define the fracture strength of schistose rock during crushing. Fracture strength was shown to decrease as the fabric aligned with the principal axis of loading. One of three types of characteristic stress-strain behaviour are defined by the orientation of the fabric with respect to the applied stress.

Jan 1, 1993

Knowledge of the hydrogeological setting of a mine forms an integral part of a mining operation. Groundwater impacts, initially, on mine feasibility. Then, on commencement of mining, it interacts on the operational components of dewatering, water supply, tailings leachates, mine wall stability, stormwater run-off, water disposal, impact on regional environment and mine closure planning. The recording of hydrogeological information is frequently overlooked during resource and reserve definition as well as during the course of mining when prime opportunity exists for the collection and collation of this data. In recent times, the exclusion of hydrogeological data has been exacerbated by use of high air pressure drill rigs that exclude water inflow. The recording of water data has been further inhibited by the use of computer coded drill logs that do not include the site geologistÆs or drillerÆs comments on drilling problems and observations associated with groundwater intersections. Geologists now infrequently directly supervise drill rigs, but visit the rig only intermittently to evaluate drilling progress. They do not see first hand drill performance characteristics at water make zones. Drill cuttings, as drill chips and cores, are now mostly logged away from the drill site so that wet sample locations, visual water flow evidence and verbal comments from the driller are not recorded. As a result, mine geologists now do not direct adequate attention to the delineation of lithologies and structures that store and transmit water. This paper provides examples of water sighting and recording techniques applicable to a mining operation. Examples are also provided where hydrogeological conditions have been disregarded with serious impact on the progress of mining. The recording of hydrogeological data should be maintained and formatted by the site geologists into a useful database for review as and when required by specialists in hydrogeology, geotechnical and mining engineering and the environment. The information can be coded by the site geologist for inclusion into the mine database. A groundwater dataset, compiled during the progress of field investigations, will save the considerable cost of re-drilling and hole re-entry testing which would otherwise be required to provide base level hydrogeological information required for progress of mining. Apart from working mine use, a hydrogeological dataset is a necessary component for planning mining closure and mine legacy conditions.

Jan 1, 2003

Interpreted geologic domains provide the geologic architecture of many current models used to estimate the potential economic resources in mineral deposits. The spatial extent of each domain is usually defined by a three-dimensional wireframe or triangulated surface.The set of geologic wireframes forming part of a resource model might generally be called a spatial interpretation of some set of geologic features coincident with the mineralisation, based primarily on logged and mapped properties of the samples and other exposures of the mineralisation. The interpreted spatial distribution of rock type, alteration and grade of drill hole samples above a particular grade threshold are commonly used criteria in constructing the geologic domain wireframes. Frequently, the grade threshold is closely related to the anticipated economic cut-off grade. The boundaries or spatial limits of different domains are most commonly defined as æhardÆ or æsoftÆ. A æhardÆ boundary usually means no dependent relationship of any kind is defined between the properties of samples inside a particular domain wireframe and those samples outside the wireframe. A æsoftÆ boundary commonly implies that some kind of dependent relationship does prevail between the properties of samples inside and outside the particular wireframe. Many ways are used to describe those relationships, few of which are based on spatial analysis of the continuity of sample attributes across the domain boundaries. In local estimation procedures such as ordinary block kriging, æhardÆ boundaries act as a total barrier to the influence of samples on either side of the boundary depending on the location of the block being estimated. In some instances, æsemi-permeableÆ boundaries are used in which the samples inside a domain wireframe are allowed to influence the estimates outside but not the reverse. This can lead to many undesirable effects in estimates of block grades.This paper discusses the value of this approach to geologic domaining from a viewpoint of model complexity, as well as in relation to the implications for both linear and non-linear estimation methods and contrasts it with alternatives. It also explores some important consequences of using æhardÆ and æsoftÆ geological boundaries with the commonly used modelling methods: excessive smoothing of estimates near domain boundaries and conditionally biased estimates of grade at the global and local scale.

Sep 26, 2011

A shift in the present day oil exploration scenario from West Coast can be foreseen keeping in mind peak of exploration in Cambay Basin and fast pace of development in Bombay High and its associated fields by the end of this century. Shifts in exploration from structural traps to stratigraphic traps, techno- logical development to drill in deep waters, improving economic situation for oil ventures and proven oil and gas potential of East Coast basins suggest that Indian oil explorat- ion scene will be at its peak along east coast during early 21st century. Hydrocarbon shows in Poonch and Jawalamukhi in Punjab Basin, improvements in drilling to greater depths, better seismic data aquisition, good source rock potential of Subathus and its equivalents and large geologi- cally mapped structures will reopen new avenues for explorationists. Not much exploration effort has been put up so far in Ganga Basin. Keeping in mind size of the basin, sedimentary thickness involved, presence of algal matter deposited in shallow marine environment & higher hydrocarbon indications warrant active exploration. Gondwanas in India having such a large sedimentary area can not be ignored keeping in view generation and production from the non marine sediments of Kenya, Chad, Sudan, Gadon and China. Gondwanas become all the more important in view of gas production from their equivalents-Karoos in Ethiopia and South Africa. In all, above mentioned changes can be predicted in Indian oil exploration scenario during 21st century.

Jan 1, 1986

Problems associated with gas management become more significant as exploitation of coal reserves in the Bowen Basin in Australia becomes deeper. At Oaky North mine, relocation of production from one area of the mine to another with a higher gas content required the use of pre-drainage, post drainage and inertisation techniques to enable production activities to continue largely uninterrupted. Innovative surface to inseam drilling techniques were developed for pre-drainage of reserves close to mine workings and have proven to be largely successful. The gas management techniques adopted and specific experience gained are discussed in this paper.

Jan 1, 2005

In the stability assessment of open pit walls, geotechnical engineers have to deal with uncertainty related to structural geology, rock mechanical parameters, groundwater and so on. This uncertainty will immediately and significantly impact on wall stability assessment and therefore. influence mineral recovery and ultimately the financial return of open pit mining. However, the conventional factor of safety applied to measure the stability of slopes and the relevant analytical computer packages cannot quantitatively consider the variability or uncertainty of the input data. As a supplement, therefore, geotechnical engineers have begun to apply probability to the stability assessment of open pit walls over the last two decades. To-date unfortunately, no powerful computer package is available to geotechnical engineers to conduct the probability analysis of slope stability. This paper presents a computer package of probability analysis for rock and soil slope stability. In this computer package, the strength parameters of rock and/or soil material such as cohesion, friction angle and unit weight of the different rock and/or soil type domain in a complex structural geology environment can be considered as the basic input random variables. Groundwater level can also be taken into account as a random variable in this package. Two `rigorous' limit equilibrium solutions, the Morgenstern/Price method and the Sarma method, can be used to calculate the factor of safety during Monte Carlo Simulation applied in this program. Five types of probability distribution are included in this package for the user to simulate basic input random variables. Two realistic cases from BHP Iron Ore are used to illustrate this package.

Jan 1, 1997

Process variables in flotation circuits are outlined with a view to producing mathematical models of circuits. The nature of the kinetics of flotation are discussed and the effect of process variables on the kinetics considered. An approach for a possible model is briefly outlined.

Jan 1, 1971

By Pratt V, Davis K

Challenges facing middle management in the 1980's and beyond are not confined to business matters such as industrial relations, government and legal constraints, corporate takeovers, and commodity marketing. More particularly they deal with people issues and the interrelationship of corporate/ family relationships. There is a need for corporations to acknowledge the growing conflict between corporate/family roles being brought about by such matters as equal opportunity, double professional marriage partnerships, personal mobility and the increasing stress faced by managers as a result of current demands and expectations being placed on them. While the main responsibility for managing professional life as well as the relationship between professional and private life rests with the individual executive, corporations nevertheless have a major responsibility to assist these executives in this management process. Corporations in Australia are taking steps to address this situation but much more needs to be done. This was highlighted in the March 1985 "Middle Management" course with its associated Spouses Programme presented jointly by Australian Mineral Foundation and The Australian Administrative Staff College. Effective communication is at the heart of the matter but no amount of training on this subject will bear fruit unless there is an associated commitment by executives to improve the effectiveness of their communi- cation process both in their corporate and family roles.

Jan 1, 1986

For some time fine coal (-0.5 mm) flot ation has been considered as a bulk flotation problem. Combinations of hydrocarbon oils and frothers have been used as surface active agents in coal flotation. The selectivity of the flotation process has always been poor in such cases. With the increase in fine coal production due to mining methods and coal handling systems, optimisation of fine coal treatment.has become important. Petrographic and mineralogical composit- ions of coal particles have been reported to influence their flotability. The problem becomes more complex due to surface oxidation of coal and the presence of slime forming clay minerals in the run of mine coal. In this paper, the flotation problem is examined on the basis of various constituents of coal and their associated gangue minerals. The selection of reagents has been suggested on the basis of their surface chemical properties. Factors such as surface modific- ation of coal and gangue materials, flotation kinetics and hydrocarbon oil - coal inter- action have been critically evaluated to improve fine coal flotation recovery.

Jan 1, 1978

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

By T Goswami, M Edmondson

Henry Walker Eltin (HWE) are the mining contractors for Gloucester Coal at Stratford mine, which is in an environmentally sensitive area in the Avon Valley, NSW, Australia. Normal blasting at Stratford is done in a æstand upÆ or æbox cutÆ mode to suit the truck and shovel operations. Recently an opportunity of doing a throw blast became available when part of a ramp had to be blasted to accommodate changes to the pit design while not damaging the remainder of the ramp. The objective was to maximise throw into the void in order to minimise excavation costs by reducing the amount of overburden to be moved by the excavation fleet. It was necessary that the best result be achieved while staying within the vibration and airblast limits at a neighbouring property and nearby township. Both objectives were achieved through the application of OricaÆs knowledge of blast design, modelling and i-konTM electronic detonators. The i-kon system was used because of its known benefits in cast blasting and environmental control. The i-kon system provides the blaster with much greater accuracy, control and the flexibility to tailor blast designs. It has been found previously to enhance blast throw and provide cleaner high walls (Brent, 2002). The blast was a success, producing a muckpile with a high degree of looseness and consistent fragmentation, with an average throw to final spoil position of 37.5 per cent. This was achieved without any environmental exceedance. In addition, high speed filming showed that the coal edge had remained largely in place, indicating minimal coal loss. The results exceeded the expectations of HWE Stratford and the overall cost savings to HWE Stratford from this blast were recognised to be substantial. Further throw blasting opportunities at Stratford have been followed using the i-kon system to maximise benefits.

Jan 1, 2003

By R Carreau

The results of a detailed acid rock drainage (ARD) prediction program were used to revise the waste rock segregation criteria at the Restigouche open pit mine. Waste rock at the site was predominately derived from altered volcanic rocks that hosted a massive sulfide lead/zinc orebody. The program assessed the five years of drainage chemistry from both the potentially acid generating and the non-acid generating waste rock storage facilities in addition to laboratory-based kinetic test results. Material-specific leaching characteristics including relative metal-release rates and neutralisation potential depletion rates were determined from 12 laboratory-based kinetic tests. Solid-phase analyses indicated that, although pyrite was typically the most abundant sulfide mineral in the waste rock, its abundance varied significantly as documented by total sulfur contents ranging from 4.0 per cent. Kinetic test results were used to establish revised waste rock segregation criteria based on total sulfur content and neutralisation potential. The revised criteria maintain that waste material with a total sulfur content 4.0 per cent as potentially acid generating. When present in sufficient quantities, ankerite provided an effective source of neutralisation potential for the range of observed sulfide oxidation rates. Kinetic testing documented that up to 6 kg CaCO3/t was ineffective at neutralising acidity in samples that contained >4 per cent S. The carbonate molar ratio measured from the humidity cells was adjusted to reflect the stoichiometry of the ankerite and applied as an NP/AP criteria for waste rock containing 0.1 <S per cent <4.0.

Jan 1, 2003

By Swain H. D, Kay R. L

Assessment of mineral reserves in any ore- body hinges on both mineralisation characteris- tics and the economics of extraction. The mineral reserves statement depends on interpre- tation of diamond drill information by geolo- gists, determination of the production plan and operating costs by mining and metallurgical engineers and prediction of future income by economists. The techniques used to generate the mineral reserves statement for Bougainville Copper Limited in 1969 are described and the accuracy of predictions discussed. Preliminary results from a geostatistical reassessment are comp- ared with the ore zone model, blast hole data and concentrator reconciled production results.

Jan 1, 1979

Recognition is the most important aspect in the use of breccias as an exploration tool. Ore-hosting breccias occur in a wide variety of environ-ments, shapes, compositions and characteristics, but generally present favorable loci for the deposition of ore mineralization in epithermal, porphyry copper-gold-molybdenum, massive sulfide, carbonate-hosted, sedimentary lead-zinc deposits and others.

Jan 1, 1990

By Wall J, Platell R, Knight P

The Argyle diamond mine is located in the East Kimberley area of Western Australia, some 100 km south of the town of Kununurra. The diamondiferous Argyle olivine-lamproite diatreme was discovered in August 1979. Production began in December 1985 at a planned throughput of 3 Mtpa to recover 25 million carats of diamonds. Presently, Argyle is the world's largest producer of natural diamonds and produced over 40 million carats in 1993 from seven million tonnes of lamproite ore treated. Two phases of evaluation have been carried out. The first in 1981-82 was designed to prove around 60 million tonnes of ore to justify the establishment of a mine with a minimum life of 20 years. The second phase, in 1989-90 involved drilling the orebody to greater depths to provide data on which to plan the final pit design. The final pit contained 120 million tonnes of ore at 5.3 carats per tonne (ct/t) grade. Mining of the planned pit will extend the mine life to around the year 2004, following which it is possible that a further cut-back could be mined. There is also the potential for future underground mining. A substantial amount of geotechnical work has been undertaken due to the fact that the pit will be nearly 500 m deep and is located in a mobile zone causing abnormally high residual stresses to occur in the pit walls. The occurrence of low strength rocks at depth in the pit walls further complicated the situation. Hydrogeological investigations were done to determine pit dewatering requirements and to assess the effect of dewatering on pit wall stability.

Jan 1, 1994