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By T Roberts, D Faulkner, G Watt

Traditional mechanised resin rock bolting in hard rock underground mines requires the installation of resin capsules into a pre-drilled hole prior to the rock bolt being spun into a hole to mix the resin and set the bolt in place. In poor rockmass conditions, especially at depth or in highly altered faults and shears, the condition of the holes often deteriorates as the poor ground around it unravels and falls into the hole. This results in partially or fully blocked holes that either damages the resin capsule when they are being inserted into the holes or prevent it entirely until the hole is continuously cleaned of debris. This deterioration of the hole condition, and continuous need to clean and re-drill holes, also increases the diameter of the hole which in turn affects the continuously mechanically coupled anchorage mechanism of the rock bolt to the rockmass as there is simply not enough resin in the hole to fill the annulus between the bolt and the rock. This results in a large increase to critical heading cycle time and, more importantly, results in the rock reinforcement not performing as per design specification and increases the risk of instability. To overcome the quality control issues with resin bolt installation in poor ground, a single pass drill, install, inject and tension self-drilling resin bolt application was designed and implemented for use in such conditions. This system allows the operator to inject a two part polyester resin through a self-drilled hollow bolt to mix and fully encapsulate the rock reinforcement. The self-drilling bolt allows for post injection of the hole after the bolt has been installed into the rock and gives the operator manual or automated control on the amount of resin used in the hole to ensure complete encapsulation and continuously mechanically coupled anchorage to the rock. This allows the reinforcement to work as designed and provide the Geotechnical Engineer extra quality control confidence in these conditions. The implementation of this single pass resin bolting system resulted in significant decreases to the resin bolting cycle time and rock bolt quality control failures. In this paper the design, implementation and embedment into the development cycle will be discussed and the in situ quality control checks used to validate the increase in rock bolt installation quality will be shared. CITATION:Watt, G, Roberts, T and Faulkner, D, 2018. Single pass drill, install and inject self-drilling resin bolt application in poor ground, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 323–343 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

South Africa is the world's largest producer of gold. The survival of its gold mining industry is dependent, to a large extent, on the successful implementation of new mining technology which reduces the operating costs. Gold mines of the country have a record of a high operational cost per tonne of rock excavated. The geology of the gold-bearing rock, in addition to the mining depth and the gold recoverable grade, profoundly affect the profitability of the industry. Among the other mining operations, drilling and blasting take a fair share of the mining cost. It is therefore proper to implement a dynamic approach of technological review aimed at combating the escalation of mining costs. Over the years, the industry has moved away from labour intensive activities. Mechanised operations are introduced where possible. Management techniques are oriented more towards better utilisation of human resources and machinery so as to enhance productivity in the stopes. This paper addresses the issue with particular reference to blasting operations in the stopes of deep gold mines. It reviews the conventional drilling and blasting techniques. It outlines some innovative changes brought about in the course of recent years with the aim of optimising productivity and the stope efficiency in particular. It focusses on the peculiarities of the blasting technology in deep mines. It discusses the issue of interaction between the high stress fields underground and the blasting generated stresses on rock fragmentation, as well as their impact on the remaining excavations. It anticipates the concept of the new technology of selective blasting in stoping. Finally it puts forward the crucial role played by management of the human factor underground.

Jan 1, 1995

The story of the rise, progress, and development of our modern railway system is a long but an exceedingly interesting one. The phases it has passed through, the discussions that have arisen from time to time on the most economic modes of construction and working, and the final result these various discussions have led to, are full of importance and interest to the engineer. It is not my intention to deal historically with the subject. I desire simply to speak to the requirements of the hour in Australia. It will not be disputed, I think, that these colonies have reached a point in railway construction and management when, if additional lines to any extent are still to be built, a different principle must be adopted. There are yet large tracts and areas of country to be tapped by the rail and the locomotive, which for years to come must remain untouched if the same expensive gauges and modes of construction are continued. We have yet to see clearly the necessity of introducing a system of light lines that will pay their own way and at the same time augment the traffic of our main lines. This question really no longer remains an unsolved problem. It lies, in a few words, in the acceptance of the, narrowest gauge and the simplest mode of construction that can constitute a pacticable railway. I fear it is hopeless to suggest that private companies should be legally permitted to construct such lines. It seems as if it were next to impossible to move official authorities to enter upon the construction of lines on this principle. It is, all the same an undoubted fact that if private companies could obtain Acts of Parliament, that in several of the colonies a new impetus would be given to railway construction.I may point out that not only has the principle of narrow gauge light railways been adopted in India but private companies are obtaining power to build them. Outside of :England many narrow gauge lines have been made, and in France, Denmark, Italy, and Sweden they have been highly successful.

By C Kocsis, G Baiden, Y Bissiri

CANMET-MMSL and Penguin Automation Systems Inc have been exploring how process simulation and ventilation modelling software, when combined, can be used to optimise hard-rock/metal mine ventilation systems. In combination, it is anticipated that this methodology will facilitate the exploration of mine design options that affect ventilation requirements and ultimately cost. Such integrated mine design could limit, and possibly reverse, the drivers that under current practices would generally dictate increased ventilation, power consumption, cost and greenhouse gas emissions. It is believed that the mining industry needs such process models to develop better business cases. For example, the implementation of optimised ventilation systems will undoubtedly require significant investment and mines are often reluctant to try such conservational measures unless they can be proven cost-effective. In general, Canadian hard-rock mines know their ventilation systems are providing too much air and consuming power unnecessarily. This is because their systems are designed to provide maximum production flexibility, based upon peak demand, which may be at some future time, and operated continuously at that level regardless of actual need. Simplistic analyses have shown electrical energy savings can range from 30 per cent through to 90 per cent (Hardcastle, Gangal and Leung, 1998). These savings depend upon such factors as the intensity and continuity of the production schedule as opposed to non-productive time. Where these savings occur is also important, if limited to either the primary or auxiliary ventilation systems, they could be negligible in a mineÆs total energy consumption. The problem these mines face is determining what level of ventilation is required in real-time and then the relative benefits. Such parameters as varying electricity costs, heating fuel options, different design criteria and their complex inter-relationship can effect the selection of an optimal system, depending on whether energy, environment or cost is the prime driver. The use of process simulators in underground mining is in its infancy; to date they have been used to show the benefits over the life of a mine under different mining methods, such as a comparison of tele-remote mining from surface against conventional manned operation (Baiden, 2000). This ongoing development advances the use of such simulators into a new and potentially important area, namely modelling the life-cycle ventilation requirements of a mine. This paper shows how such a life-cycle analysis as opposed to peak demand can provide the basis for optimising the design of ventilation systems and their control.

Jan 1, 2005

By Kennedy JT

This is a question that will be asked many times and by many individuals during the various evaluation stages of any new project. However, the question itself will often have different connotations to the different groups invariably involved in such an exercise. As examples, consider just three of the several different groups involved in the development of a new mining project - Financiers, Consulting Engineers and the Sponsors of the project (potential borrowers). To the Financiers, a 'bankable project' will be one against which they will be prepared to lend funds (but not necessarily all of the funds requested by the Sponsors). This usually means that in the first instance the technical information presented to the bank has satisfactorily covered all of the requisite areas to the levels of accuracy required. More importantly, the financial evaluation of the projected economic performance of the mine, as a whole, is considered sound and a set of arrangements under which the bank is prepared to advance loan funds have been structured which fully satisfy the bank's credit criteria. To Consulting Engineers preparing a feasibility study (or a part thereof), on behalf of the project Sponsors, the term 'bankable' invariably only refers to the technical completeness and the level of detail contained in the report which they are preparing. Their scope of work will not necessarily have been broad enough to fully satisfy a bank's requirements. It is unusual to see any specific references to overall project viability or profitability in Consulting Engineers' feasibility reports, other than those which are automatically associated with the use of the term 'ore'.

Jan 1, 1990

To obtain the best economic results in treating the comparatively high-grade ore of the Kalgurli Mine a good roast is essential, and the effort of this paper will be to briefly describe the plant and the conditions prevailing in roasting, which, on an output of about 360 tons daily, subsequently enable an average extraction of slightly over 94% of the gold to be maintained.The percentage of sulphur in the ore varies between 2'5 and 3'5, the lower figure existing when treating oxidized ore. The average gold value is 13 dwt; this occurs chiefly as sylvanite, containing .a lower percentage of silver than is usually present in that mineral. One ore body in the mine contains hessite (Ag2Te) in considerable quantity, associated with gold telluride, and when ore from this stope is being treated the silver contents rise to as high as 20 dwt, but the usual amount is about 9 dwt. per ton, of which only a small proportion is extracted. Other metallic minerals, in addition to pyrite, occurring more or less commonly, are arsenopyrite, magnetite, chalcopyrite, and the tellurides calaverite (AuTez)and coloradoite HgzTe3). A small proportion only of the value occurs as free gold.

Jan 1, 1911

By J Harris, P Kirsch, R LaBouchardiere

æMining + Health in DevelopmentÆ is a project funded by the International Mining for Development Centre (IM4DC, 2012) to develop a centralised database of corporate sustainability initiatives for managing and improving occupational and public health, based on information extracted from social and environmental reports of major mining, oil and gas (MOG) companies. This register of materials has the potential to increase stakeholder awareness of the unique health risks impacting the minerals industry, employees, their families and surrounding communities, as well as to inform stakeholders on global industry approaches to health management.Data and preliminary outcomes from analysis of different MOG corporate sustainability reports on public health and disease management are presented for six African countries (Democratic Republic of Congo, Ghana, Mozambique, Sudan, Tanzania and Zimbabwe) and six Asia-Pacific countries (Indonesia, Mongolia, Pakistan, Papua New Guinea, Philippines and Vietnam).With the minerals industry facing ongoing rapid growth worldwide, including continuous expansion into developing regions, the æMining+Health in DevelopmentÆ project will inform industry, civil society and regulators of current health management practices and programming among the different sectors of the minerals, oil and gas industries and across various regional operations. This baseline information will serve as a resource for minerals industry managers, providing a forum for sharing best practice health management approaches amongst MOG companies.CITATION:LaBouchardiere, R, Harris, J and Kirsch, P, 2012. Mining and health in development - An inventory of global resource industry health initiatives in developing countries, in Proceedings International Mine Management 2012, pp 75-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Lu S, Jiang Y

The conventional transportation system in open pit, a to u.* itc:,~> truck., to carry the ore along the ramps. Normally, the transportation distance increases greatly as mining progresses deeper. A new approach to overcome the above disadvantage is to adopt a buried roadway by which ores is transported by conveyors from the mining area to the outside dump in the shortest distance so that the production efficiency is greatly increased. Maintenance of the buried roadway in a good working condition is the key factor that determines the success or failure of the proposed approach. This includes the determination of support load, types and structures of support and other related supporting measures. The crucial problem here is to effectively control the load applied on the buried roadway in a certain range that the ordinary support can stand. Based on the theoretical analysis, numerical modelling and physical simulation testing using equivalent material, this paper studies effects on control of the support load by adopting certain measures, for instance reinforcing the surrounding rock and placing the extendable layer between the support and a rock mass. Furthermore, the influence of the dynamic load induced by the movement of heavy vehicles on the stability of the buried roadway is also investigated.

Jan 1, 1995

Multiple regression analysis applied to ventilation records of stopes on the Witwatersrand showed that it was possible to estimate the temperature increase per 100 ft for a new stope with a standard deviation of 0' 5°F. The analysis also threw light on the relative effect on this estimate of five different factors.Application of the analysis of variance technique to a factorialexperiment on the production of dust during rock drilling showed that the effects of air and water pressure were quite small but also showed that the between-machine variation was unexpectedly large.Analysis of variance also proved a valuable means for assessing the bias and random error variation of aneroid barometers used in pressure surveys.INTRODUCTIONThree examples are discussed to illustrate the use of the techniques of "analysis of variance" and "multiple regression" in research on the ventilation of gold mines. Although the techniques are basically similar their application to each example has a slightly different emphasis and the examples were chosen for this reason. The variation ofemphasis is as follows.1. Temperature increases in stapes. This work was undertaken as a preliminary to possible extensive controlled experimentation (Lambrechts, 1959). Data collected in routine work by the mine ventilation personnel were used for analysis and no specific experiments were carried out. The main object was to see whether such data could provide any strong pointers to factors which might be worthy ofmore careful study and to factors which could initially be ignored. Of course, there was hope that the study might provide an empirical formula for rough forecasts.

Jan 1, 1962

If an orebody has been drilled to achieve some level of regulatory compliance, then a number of associated geological databases will exist, representing 10 000 to 100 000 m plus of core intervals. The databases usually contain data about assays, lithology, mineralisation and geophysical attributes. They will also include location information such as collar positions and downhole surveys. Obviously this data is collected by geologists for, predominantly, geologists and mining engineers. However, from a process design viewpoint process engineers usually ignore the geology where possible and rely on a small number of metallurgical test samples. Typically these test samples are sourced from convenient and available cores or from a small number of specially drilled metallurgical holes. One of the worst instances known to the author was the design of a SAG mill using only two SAG specific test results (one for each of the major ore types) while, geologically, the orebody was defined by more than 30 000 m of drilling. This paper sets out a philosophy to maximise the use of the geological data, both for process design and in preparation for the commissioning phase of projects. Geological data is used in the identification of preferred locations for metallurgical test samples, for checking the metallurgical validity of the geological ore-type definitions, where necessary developing new ore-type definitions (geometallurgical domains) and developing mathematical relationships for the estimation of important metallurgical factors across the geological database. If the estimation of factors (for example ore competence) is considered reliable enough then there is also the possibility of feeding calculated data back into the block modelling process to allow the generation of metallurgically relevant outputs in the mine plans.

Jan 1, 2007

By S A. Prevec

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Traditional models employed to genetically link associated chromite and platinum-group elements have favoured crustal contamination as the primary process for inducing sulfide and oxide saturation. The association of chromite ores with crustal contamination is well established in the literature. However, in the 1970s (cf Irvine, 1973, 1975), Irvine demonstrated that crustal contamination was in fact problematic as a tool for inducing chromite precipitation in mafic to ultramafic magmas. His results are re-examined here, along with some attempts to reconcile them with the effects of adding Fe to the models. It is concluded that crustal contamination is indeed problematic based on phase relationships alone. However, the role of fluids as a compensating agent is evaluated, which may explain why crustal contamination may indeed facilitate oxide and sulfide precipitation.CITATION:Prevec, S A, 2015. Chromite and platinum-group elements coprecipitation by crustal contamination or magma mixing revisited – genetic and exploration implications, in Proceedings PACRIM 2015 Congress, pp 311–316 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

On the 18th November, 19'58, the first coal was delivered to the Morwell Power Station from the adjacent Open Cut using conveyors for the transport of the coal from the working face to the boiler bunkers. As the cut develops the coal seam will be worked for its full depth of about 360 feet from four benches, each feeding a conveyor line along th.e face and up out of the cut to the power station and briquette factory. By 1970 the estimated maximum daily demand reaches 60,000 tons and the total annual output 18 million tons. The complete conveyor installation will then total some 9 miles with a capital cost of over £3~ million.The choice of conveyors in place of the more usual rail system was made possible by the development of movable belt conveyors which use mechanical conveyor shifting, high belt speeds and flexible high strength belts and the paper deals with these and some other aspects of the scheme.INTRODUCTIONThe development of brown coal deposits is usually based on open cut workings equipped with a few large dredgers giving an almost continuous output of coal or overburden which has to be hauled a comparatively short distance. These are ideal conditions for conveyor operation, and it is surprising that, until recently, rail transport has been used almost exclusively in brown coal open cuts. In some cases inclined conveyors have been introduced to take the coal from the coal levels up out of the cut to bunkers at groundlevel, but trains have been left to operate between the ditch bunker feeding the conveyor system and the dredger.

Jan 1, 1960

By Stein A

The general mechanism of recrystallisation for cold worked metal is well established, and need be only briefly summarised with a few references to recent articles which clarify minor points. The types of extension, whether by stretching, drawing, hammering, rolling, etc., do not alter the general principles (1), although quantitative results may differ somewhat, particularly with regard to differences between the surface and interior of samples.These principles can be summarised as follows: The first stage in annealing is a recovery (sometimes known as relaxation) of physical properties such as hardness, elongation, etc., without any appearance of recrystallisation; the second stage involves a further alteration in physical properties, accompanying the formation of new recrystallised grains which replace the original structure; a possible third stage involves an increase in the grain size of the completely recrystallised structure by absorption of smaller grains by larger ones. These three stages will be referred to as recovery, recrystallisation, and grain growth. Depending on conditions, the three stages may be clearly marked or may occur more or less simultaneously.For a given annealing temperature, cold deformations below a certain amount fail to give recrystallisation, and the final structure consists of the original grains which have recovered and possibly become more equiaxed. When a certain deformation, critical for that annealing temperature, is given, recrystallisation can occur, and will give the maximum recrystallised grain size.Increasing deformations beyond this give progressively smaller grain sizes.For each material there is a minimum recrystallisation temperature, below which recrystallisation will not occur whatever the deformation or time of annealing. For a given deformation there is a temperature, critical for that deformation, below which recrystallisation will not occur, and above which it will take place with increasing rapidity.

Jan 1, 1947

By C J. Larder, S E. Turner

The concept of underground grinding is not new, but to a metallurgist and a mining engineer this could be considered unconventional. The idea of pumping a ground slurry several hundred metres from underground in a single lift could also be considered to present a daunting engineering challenge. Using a practical example of a mine in Australia where the owners have requested not to be identified, this paper challenges the conventional thoughts on these concepts and shows that with basic sound engineering practices the production of a ground slurry from underground could potentially provide significant operating cost savings. The supply of ore from the underground mine is currently drawn from depths approaching 800 m below the surface. The cost of hauling the ore to the existing underground crushing station located 500 m below surface has been steadily increasing. A number of alternatives to reduce the mining and processing unit operating costs were examined by Sinclair Knight Merz (SKM) and the mining company. The most radical of these is the use of hydraulic hoisting of ore at an increased production rate. Numerous questions were asked, such as: How does one get a SAG mill or an HPGR crusher underground? Where does one locate a grinding mill underground? Does the technology exist to pump the slurry to surface in a single lift? What will be the cost benefits? What are the risks involved? The study covered the two main technical issues underlying the potential benefits. Firstly, technical evaluations were undertaken on the pumping technology currently available for single and multiple lifts to surface. Secondly, the issues relating to the feasibility of delivering and locating a SAG mill underground were reviewed. Although the capital costs for this project are significant, the operating cost savings showed a potential payback period of less than two years, and furthermore provide the basis for an increased mine life, especially at lower metal prices.

Jan 1, 2005

While, in the past, a great deal of attention has been focussed on technical issues and the performance of explosives in rock, the explosive user, an essential link in the chain, has often been neglected. In the mining industry, too often, the benefits of excellent technical work have been degraded over time due to the lack of definitive and documented control. Using the principles of quality management a quality training system was developed and implemented for management of explosives use at Gunpowder Copper Ltd (GCL). This paper describes the structure of the system, its development and implementation, and contains practical advice and information for managers responsible for blasting and charge crews. The paper is in four parts: I Quality systems. A brief overview of the relevant aspects of total quality management that apply to explosives use. The requirements for documentation, management and auditing are explored. 2. Training for competency. The five essential elements of Competency Board Training (CBT) are examined, including auditing. 3. The Gunpowder Copper system. Implementation of the complete training system. Documentation and its control, auditing, instructions for operators, management responsibility and means of obtaining operator ownership are amongst the issues raised. Reporting requirements are the means to effectively manage change are described. 4. Summary. The paper concludes with the tangible benefits seen by Gunpowder Copper through the adoption of a quality training System.

Jan 1, 1995

The decrepitation technique is a rapid means of measuring abundances, temperatures and to some extent the fluid compositions, of fluid inclusions in transparent and opaque minerals. The method has been used to investigate the hydrothermal fluid systems associated with gold mineralisation in the Tennant Creek, Pine Creek and Halls Creek Goldfields. At the Enterprise Mine, Pine Creek, several different stages of quartz veining are distinguished and within these, gradational changes in fluid temperatures and compositions help to define the centre and nature of the thermal system responsible for the mineralisation. In the surrounding Pine Creek region and at Tennant Creek and Halls Creek, the results were applied on a regional scale to characterize outcrops and aid in the discrimination between potentially mineral- ized and barren outcrops. The decrepitation method involves the heating of a small (lgm) sample of crushed and sized grains up to as high as 800 degrees celsius. During the heating the fluid inclu- sions within the grains develop sufficient internal pressure to physically burst, the temperature of such bursting being dependent on the type of fluid and the prevailing tem- perature at the time the inclusion was originally trapped. The resulting tabulation of the number of inclusion bursts per 10 degree temperature interval is plotted as a histogram of decrepitations versus tempera- ture and called a decrepigram. The decrepi- grams frequently show several distinct peaks at different temperatures which are caused by different populations of inclusions in the sample. The areas of the peaks indicate the abundances of inclusions in each population while the shape and mean temperature of the peak provides a guide to the type of fluids involved. Of particular importance in this study is the presence of decrepitation peaks at fairly low temperatures (around 2000 C. These are characteristic of C02 rich fluids which build up internal pressure very quickly when heated. The Enterprise Gold Mine at Pine Creek comprises a number of overlapping quartz vein systems hosted by Burrell Creek Formation sediments. The geology of this mine has been described at this conference by Dann and Delaney, who have defined several distinct stages of quartz veining based on structural, mineralogical and physical features of the veins. For this decrepitation study, 19 quartz samples from the mine and environs, including some from each stage of veining were collected. These results suggest that there are 4 major vein types, within 3 of which additional small variations can be discerned which are due to gradational changes in the temperatures and fluid compositions in the mine area.

Jan 1, 1984

By Holla L

There exist several legislative provisions in N.S.W. which work together to control surface subsidence due to extraction of coal by underground methods. The important ones are the Coal Mining Act, Coal Mines Regulation Act, Mine Subsidence Compensation Act and Dams Safety Act. In addition, there are guidelines laid down by the Chief Inspector of Coal Mines for mining under and in the vicinity of tidal waters and the ocean. There are also conditions of coal mining leases and conditions of approvals given to undertake various methods of mining which stipulate further controls. The legislative provisions and relative controls are designed to minimise surface damage, ensure safety , of major public utilities, control- surface land use and compensate damage caused by subsidence as a result of coal mining operations. They aim at balanced and responsible development of our valuable coal resources consistent with adequate safeguards to surface improvements and natural features. The paper discusses in detail these legislative provisions and the mechanics of their operation with a view to emphasising the fact that underground coal mining operations are undertaken responsibly and in a planned and rational manner for the overall benefit of the community. Further, the paper aims to demonstrate the need for legislative measures and conditioning of mining operations to keep abreast of developments in the knowledge and skills of mining and subsidence engineers and continuing improvements in mining technologies. Likewise there is a need on the part of engineers and those associated with introduction of new technologies to appreciate the requirements and existence of legislative and other measures having a direct or indirect association with surface subsidence as a result of coal mining operation.

Jan 1, 1986

By A R. Gerson

Pyrite, chalcopyrite and mixed sulfide samples, with and without quartz (5 wt per cent S), were subjected to column leaching to mimic natural weathering (cyclic wetting and drying). The pH and SO4 2- concentration of the column effluent was measured over a period of 78 weeks. The pH of the pyrite-only containing column rapidly decreased and remained under pH 4 after 12 weeks of leaching. The pH calculated assuming a 2:1 ratio of H + generation and SO4 2- release was slightly lower than that measured. However, a reduced H + to SO4 2- ratio of 1:1 is predicted if the release of aqueous Fe 2+ is assumed rather than the formation of Fe(OH)3. The pH of all columns containing only chalcopyrite or a 1:1 mole ratio of chalcopyrite and pyrite remained at or above pH 5 for the duration of the leach even though significant SO4 2- was released. One column containing the same initial surface area of pyrite and chalcopyrite but only approximately 0.10 the mole fraction of S as chalcopyrite maintained a pH of greater than five for the first 56 weeks of leaching and showed sporadic acid production thereafter. It is well established that oxidation of chalcopyrite results in a surface layer of polysulfide material. It is the formation of polysulfide that neutralises the acid produced on S oxidation through to SO4 2-. Hence where polysulfide formation occurs extensively on chalcopyrite the resulting solution pH decrease will be less than that based on SO4 2- production. The oxidation rate of sulfide minerals increases with decreasing pH and hence acid formation via sulfide oxidation to SO4 2- causes the subsequent oxidation rate to increase. The addition of calcite (CaCO3)to a pyrite column not only neutralises the acid formed but also decreases the rate of release of sulfate to solution by a factor of approximately 30. This is also the case where chalcopyrite is present mixed with pyrite. The rate of release of sulfate from the mixed sulfide mineral columns (after the initial release of the sulfate already present) was between one-fifth and one-tenth that in the absence of chalcopyrite.

Jan 1, 2003

A vigorous seismic and drilling programme has been conducted over.ar area of .59000 square miles in the Roma district during the last three years. The work is Mill' in progress and although many new geological concepts have been discovered, he subsurface geology is not yet finalised. D.atailed examination has shown many variations of .section, has established the general basement trends and sedimentary thicknesses, has shown that much more of the section is marine than previously thought ~nd has indicated that any reservoirs throughout the section could be potential oil ind/or gas producers if suitable traps are located.

Jan 1, 1962

With the exeption of the United States, Canada and Russia, oil has not been around in quantity near world centres of population. Production: in Western Europe is insignificant. Japan is without production as are Australia, Southern Africa, India; Brazil, Chile, New Zealand and China. The United States is, however, a large importer of crude oil. The very fact that oil is produced generally away from centres of population means that it has to be carried by sea to the area in which it is required. There is, therefore, a constant flow of oil around the world in very definite channels.

Jan 1, 1962