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By A D. Stewart Gillies

Resource rent taxes are taxes which only become effective at such a time as a pre-determined rate of return has been achieved by an operation. Resource Rent Taxes have from time to time been considered for implementation in bothAustralia and New Zealand. The offshore petroleum industry in Australia is already subject to RRT as is the Roxby Downs (Olympic Dam) Mine in South Australia. Both the mining and petroleum taxation regimes in Papua New Guinea include a resource rent tax component called Additional Profits Tax.   The implications of the current form of additional profits tax for shareholder cash returns are that the tax burden on the operation may suddenly increase at some stage in the life of the mine if and when the threshold level of profitability for the tax to be triggered is exceeded. From that point in time onwards the cash return to the shareholders on the capital invested is greatly diminished. For mining companies in Papua New Guinea, the effective tax rate increases from 35% to 57.75% as a result of the onset of additional profits tax. This tax rate penalty is so severe that there appears to be merit in considering the concept of managing profitability through time rather than purely maximising annual pre-tax profits as is currently the case in most mining operations. This would have the benefit of deferring or perhaps preventing altogether the onset of the tax. One possible method for the effective management of profitability is through the control of average mining grade by cutoff grade manipulation.   Traditional cutoff grade theory has usually considered taxation as a direct cost at a fixed or variable percentage of annual profits. As a result of this most analyses are conducted on a pre-tax basis. If tax is included in analyses it is usually present as a time independent function of gross profit. Additional profits tax is both time, and rate of return dependent and therefore not adequately accommodated by currently accepted cutoff grade theory.   A review has been made of the effects of resource rent taxes on both the investment decision-making process as well as possible development and mining strategies which may be employed by mining companies faced with resource rent taxes. The review includes examples based on the structure of additional profits tax which is levied in Papua New Guinea.

Jan 1, 1995

The production of sulphuric acid at Port Pirie by the contact process began in March 1924 with the commissioning of the Electrolytic Zinc Co.'s roasting and acid plant. This plant, operated by B.H.A.S. Pty. Ltd. on behalf of the E.Z. Co., continued to produce sulphuric acid from the gases evolved when roasting Broken Hill zinc concentrate in mechanically rabbled furnaces until September 1954, when the plant was closed down.In this peri9d of approximately 30 years some 600,000 mono tons of 98·5 per cent sulphuric acid was produced, most of which was used for fertilizer production at Wallaroo and Port Adelaide. During World War II 14,400 mono tons of the above was produced in the form of 20 per cent Oleum and railed to the Salisbury Munitions Factory for use in the production of nitro-glycerine, gun-cotton and T.N.T.In the early post-war period various ways of converting at least some of the sulphur in the gases' discharged to atmosphere from the lead sintering plant were considered until, in 1949, it was decided to erect a modern contact acid plant. Much work remained to be done on the roasting plant to produce a gas of suitable grade for the contact process and also on the design of a purification section suitable for the treatment of D.L. gases.The acid section itself, however, was largely of conventional design and it was therefore decided that this would be erected first. To it was then attached a sulphur-burning section to allow it to operate as a "hot gas" brimstone acid plant until the roasting and gas purification plants had been designed and erected. In this way the urgent need for sulphuric acid in the fertilizer industry would be relieved, to some extent at least, as soon as, possible.

Jan 1, 1956

The tenth annual Mine Resale Evaluation was held in conjunction with the RMCMI 2001 convention at the Steamboat Springs Sheraton Resort, Steamboat Springs, Colorado June 23 through 26. The purpose of the mine rescue evaluation program is to provide an opportunity for mine rescue teams to learn new skills and improve their existing ones in a non-competitive environment. Several staged ?disaster? scenarios were held where the teams are called upon to exhibit their life saving abilities. The evaluators meanwhile are offering suggestions, both verbal and written, to help the teams better understand the situations presented them. This non-competitive environment allows the teams to work together and share their knowledge with fellow mine rescue teams providing everyone with a positive learning experience. Mine Rescue Chairman Bill Balaz, Balaz & Associates, was in charge of coordinating the events. Six teams consisting of seven to twelve members each (totaling 60 members) participated in the three-day event. Each ream was required to respond to direr different real-life scenarios plus a written general knowledge test daily. Cindy Burnham has assisted Bali, for a few years. Her responsibilities include grading all of the written tests. This year's tour professional evaluators included Art Seanz (Hazardous Ma¬terials) of Western Environmental Associates ; Guy Norton (Ropes), Guy Horton Rope Rescue; Mary Bailey (Medical), MBA Training and Morley Hense (Confined Space). Carolyn Durga, BHP Coal, also assisted in hazardous materials and medical scenarios. They each provided three different challenging mock situations per day per team. The teams had no prior knowledge of what the scenarios would be as details were provided only as they arrived. Ten volunteer victims added much drama and excitement to the event. Their realistic enactment, complete with false blood makeup and severed limbs, made for some very tense scenarios. The Mine Rescue Teams participating this year were BHP LaPlata, BHP Navjo, BHP San Juan, all from Farmington, New Mexico; Bridger Coal Co., Rock Springs, Wyoming; Sabine Mining, Longview, Texas; Solway Minerals, Green River, Wyoming and Western Energy Co., Colstrip, Montana. Many new friendships were made and much knowledge shared. A swap meet was held Saturday afternoon for the teams to exchange miscellaneous equipment, hats, shirts, etc. The trams were asked to evaluate the program and the evaluators. They responded with many positive suggestions that will help improve the upcoming events in the years to come. Culmination of the Mine Rescue program was a Tuesday morning awards breakfast where the teams were presented with trophies. Each member was also given a gold pin with the words Continuing Challenge - Ropes.' The pin was the first in a series that will be given over the next few years. The participating victims and evaluators were also commended for their outstanding efforts. Special signed "Victim" shirts were given to select volunteers. Sponsors for the Mine Rescue program were Flanders Electric Motors, Magnum Metals, Rocky Mountain Electric Motors, Sedona Consulting and Balaz & Associates. Many hours of volunteer tine and effort from various family members of participants helped make the 2001 event a huge success.

Jan 1, 2001

By L. E. Mordberg, E. N. Nesterova

Geochemical studies of the bauxite deposits show that the primary composition is gibbsitic. Some trace elements were relatively mobile during bauxite formation with the content of Th, U and Zr increasing and that of Rb, Ni and Co decreasing. Y and Pb were relatively immobile during lateritisation; their contents and ratios were inherited from different types of underlying rocks. The supply of Ni and Co took place at the diagenetic or epigenetic stages; their ultimate source was the crystalline basement in the region. The studies support the view that the bauxite was likely to have originated as a result of in-situ lateritisation and not through sedimentary transport and redeposition

Jun 18, 1905

By Colin Barratt

The East Side Access (ESA) project is the largest underground rail infrastructure project under construction in New York City, USA. The Manhattan segment of the project is to be mined through rock and consists of 4.1 miles of Tunnel Boring Machine tunnels for track work and mined excavations to house rail switches, air plenums, and other rail facilities. This paper considers different methods for concrete lining, such as the use of fixed forms, adjustable forms, and pneumatically applied shotcrete. The advantages and disadvantages of these methods are discussed and the basis for considering one over the other are illustrated. Further discussions on design development and preparation of documents to facilitate quality and constructability in the field are presented.

By H. Basarir

Due to the environmental constraints and the limitations on blasting, ripping as a ground loosening and breaking method has become more popular in both mining and civil engineering applications. Because of the technological advances in dozer manufacturing techniques, more powerful dozer types are available today. Thus, the ground, previously classified as non-rippable, has become rippable. As a consequence, a more applicable rippability classification system is needed which considers both equipment properties as well as rock properties in all applications. This paper is part of a complementary research work and presents the development of a previously published grading rippability classification system by the application of fuzzy set theory. The integrated rippability classification system considers the combined utilization of the rock and equipment properties, as well as expert opinion. Fuzzy set theory was chosen mainly because it deals well with uncertainty in the choice of variables. Although there are apparent sharp or discontinuous boundaries in existing classification systems, practically most of the factors involved in the ripping process are less well defined and boundaries are more blurred (or fuzzy) or uncertain in nature. Also by means of fuzzy logic it is possible to eliminate bias or subjectivity. The validity of the proposed system was checked by the comparison against existing classification systems and direct ripping production values obtained at studied sites. It is seen that by means of fuzzy logic, the uncertainties are reduced and biased usage of the final ratings that appear in alternative systems are efficiently dealt with. Keywords: Fuzzy set theory, rock rippability, rippability classification system, direct ripping, fuzzy inference system.

Jan 1, 2007

Throughout history, many of the world's achievements, conflicts and problems can be traced to the demand for minerals. With the rapid expansion of our industrialised society in recent years the demand for minerals has grown to such an extent that uncertainties about availability and cost have arisen, especially in the case of energy minerals.Minerals have acquired a new dimension for governments as the availability of these resources is interwoven with the ability of governments to achieve their developmental goals on national and international levels. Accordingly, the supply of minerals will increasingly be affected by social and political factors.

Jan 1, 1986

By William H. Lewis

Energy Research Corp., under contract to the Bureau of Mines, has developed a new miners' caplamp battery. The new battery is based on nickel-cadmium technology and offers significant improvements in performance with reduced size and weight when compared to the conventional lead-acid battery presently in use. This report describes the design and fabrication of the nickel-cadmium battery, which utilizes a roll-bonded electrode structure. The final battery design has a 15-A-h capacity in a 2-112-lb package, which is over 2 lb lighter than the present lead-acid caplamp battery.

Jan 1, 1983

By Goutam H. Shahani

Today, the mining and mineral sectors are being impacted by highly fluctuating supply ? demand, extreme price volatility and tremendous market uncertainty on a world-wide basis. This pattern is expected to continue for the foreseeable future. In particular, large consumers of tonnage quantities of industrial gases (oxygen, nitrogen) all have to make informed investment decisions in this uncertain economic environment. Plant owners ? operators need to carefully examine their current and future industrial gas needs in order to develop the most cost-effective industrial gas plant configuration. This can be done by partnering with an experienced engineering company that offers a complete technology portfolio for producing industrial gases. Ideally, the mineral and engineering companies have to work together as a single team to identify the most efficient and economic plant design. This includes an in-depth assessment of capital and operating costs, in order to deliver an optimal solution, taking plant reliability and process safety into account. It is important to consider all the industrial gas needs at a given manufacturing complex, in conjunction with available utilities and infrastructure to develop the best possible long term solution. Oxygen (O2) requirements include: oxygen enriched and oxy-fuel combustion, smelting and hydrometallurgical operations. Nitrogen (N2) is used for annealing. All of these industrial gas requirements have to be examined at a given site over a long term horizon in a holistic manner. Cryogenic air separation was first practiced at a commercial scale in 1902. Since then, the technology has been constantly refined to reduce cost; and improve reliability and flexibility. Today, using advanced engineering techniques, including proprietary process simulation, and modern fabrication techniques, it is possible to build air separation plants that are both low cost and high quality at the same time. It is important to work with an engineering company that owns a complete portfolio of industrial gas technologies, functional engineering capabilities and a variety of plant solutions. Such a partnership can quickly identify a ?sweet spot? for a given situation. By drawing on experience gained from hundreds of projects, it is possible to quickly optimize a given requirement. In situations where a customer wants a complete solution it may be appropriate to provide an air separation plant on a turn-key basis. This will enable the mining and mineral processor to focus on their core business. By using global procurement and construction capabilities it is possible reduce cost and improve project execution, thereby making industrial gas plant procurement simpler and cheaper for the mining and mineral sector.

Nov 1, 2011

Silver is one of the three major metals produced from the Broken Hill mines. The accurate determination of the silver in these ores, therefore, is of economic importance.With due appreciation of the divergence of opinion of many who are interested in the subject of the determination of silver, the writer has been prompted to present the results of some recent experiments on silver losses during cupellation and conclusions from these experiments in the present paper. The losses of silver in the fire assay for this metal are due to silver retained in the slag during the fusion or scorification of the ore, and to silver volatilized from, and absorbed by the cupel during the process of cupellation.The literature describing the results of experimental work on silver losses due to the above causes is extensive, and the general conclusion of these experiments is that the silver lost in the slag is small, but that lost by cupellation is larger and more variable.The term cupellation loss in this paper refers to the total cupellation loss, no distinction being made between the absorption and volatilization losses.Volatilization loss is shown by King to be 0.5% of the total cupellation loss and, as it is generally accepted among assayers as being only a small fraction of the cupellation loss (3) (5), it will not receive further consideration in this paper.The factors causing the loss of silver by cupellation and the precautions to be obs~rved to reduce the loss in this operation are described in (1), (2), (3), (4) and (5). The...

Jan 1, 1940

By G. F. Vander Voort

The accident at Unit No. 2 of the Three Mile Island nuclear reactor (TMI-2) on 28 March 1979 was the worst nuclear accident in US history and crippled the nuclear industry. An international Vessel Investigation Project was formed to assess the integrity of the vessel. However, it was not possible to remove specimens from the lower head until January?March 1990. Fourteen of the fifteen specimens removed by electrical discharge machining were from under the debris pile that accumulated on the lower head due to melting of approximately 19 000 kg (45%) of the core. Specimens were previously cut from the lower head of a cancelled reactor of very similar size and design destined for Midland, Michigan. These specimens were subjected to controlled heating cycles with peak temperatures from 800°C to 1100°C for periods of 1 to 100 minutes. The initial study qualitatively compared the structures in the 15 specimens from TMI-2 to the control specimens from the Midland lower head. The writer used the same specimens and employed microindentation hardness traverses, electron microprobe analysis, and selective etching followed by quantitative metallography (by image analysis) to obtain a far more detailed description of the thermal exposure experienced.

Jan 1, 2013

By J. Kuijpers

Failure and fracturing are often regarded as synonymous. While this is obviously true in an environment dominated by tensile stresses, it is still not clear how failure and macro fracturing are related in a compressive stress environment. Excavations at great depths are typically subjected to compressive stresses only. The fracturing observed around such excavations is therefore commonly assumed to be induced by such compressive stresses. The physics of such a phenomenon have unfortunately never been explained properly, so that the formation of these so-called extension fractures still remains a mystery. As the presence of fractures is an important factor affecting the stability of underground excavations, it is of practical relevance to understand their formation. In this paper, a possible explanation is proposed. It is argued that fracturing in a compressive stress environment is a secondary effect. Primary failure, in the form of micro fracturing and associated damage is assumed to precede the major fracture processes. The fractures are thus generated in response to material failure and may not directly be the cause of failure. The implications for material response and behaviour are discussed. Keywords: micro fracturing, macro fracturing, extension fractures, failure, compressive stresses, damage, excavations.

Jan 1, 2000

On the Hauraki goldfields, within the limits of Cape Colville Peninsula, the Paheozoic rocks are confined to the district north of a line drawn from Mercury Bay on the east coast to Rocky Point on the shore of the Frith of Thames. South of Kennedy's Bay they are developed on the east coast only at Kuaotunu, at which place gold mining is carried on in sandstones and slates of this age. Between Tapu Creek and Coromandel there is, along and adjacent to the shore of the gulf, a very considerable development of PaJreozoic and in part of Trias rocks, and between the Tiki Stream and the northern end of Tokatea Hill, along the western slope of the main range, lies the special area of the Palreozoic or carboniferous rocks that have more particularly to be dealt with in this paper. The same formation has a large devolpment between Cabbage Bay and the northern slopes of Moehau, and appears to the water marge on both sides of this part of the peninsula.In this part they are of special interest as having, on the west spur of Moehau, a considerable variety of dyke rocks intruded into the sedimentaries, the interest in which is increased by the fact that these dykes theIllselves are of Palreozoic age and correspond to the dykes that are so' abundant in the Tokatea-Tiki area. It is this Tokatea-Tiki area as a goldfield, and its rocks as distinguished from later volcanic' products' on other parts 'of the peninsula...

Jan 1, 1903

By S. Fuentes, J. Cáceres

"During the past fifteen years, mines utilizing the block caving method have improved performance and systematically reduced total mining costs.This paper describes improvements in mine design, mine planning, and mine management, including methods enabling the Chilean and international mining industry to ensure cost savings and productivity growth while using the block caving method. These improvements have encouraged the re-evaluation of underground operations at operating and closed open pits, and challenge surface mining applications as the only low-cost mining method. This paper describes a strategy to estimate the optimum open pit to underground transition time during the life of a mine. IntroductionDuring the last fifteen years, block caving mines have experienced huge changes in designs, planning and administration. These changes have permitted operators to drastically reduce costs, improve equipment productivity, and improve overall business performance. As a consequence of this situation, the block/panel caving mining system is challenging actual open pit operations to maximize the net present value (NPV)."

Jan 1, 2004

By Shamim A. Dar, & Samsuddin Khan, & K. F. Khan, Mohd Shuaib

The Late Paleocene–Middle Eocene phosphate nodules of Solan District of Himachal Pradesh belong to green facies of Subathu Formation of Sirmur group. Field observations indicate sporadic distribution of phosphatic nodules in the yellow brown to rusty brown, buff-colored bleach shales. Phosphatic nodules are dull earthy to dark grayish in color and break with sharp and conchoidal surfaces. Studies of phosphatic nodules using petrological microscope, X-ray diffractometry, and scanning electron microscopy (SEM) attached with energy dispersive X-ray (EDX) reveal that cryptocrystalline apatite (fluorapatite) is the dominant phosphate mineral. Silt sized silica is the dominant gangue, whereas pyrite and muscovite are present as minor gangue. The phosphate minerals occur as oolites, pellets, and cryptocrystalline apatite in the groundmass. Silica veins form a network replacing the original phosphatic matrix. Brown to brownish black color may be attributed by the organic matter in the phosphatic nodules. Completely phosphatized radiolaria and partially pyritized planktonic foraminifera are observed. There is corroboration of organic matter in the form of microbial filaments in the groundmass of apatite. The findings in the present investigation indicate that the different forms of the minerals, their texture, and distribution in the phosphatic nodules might be due to environmental vicissitudes in oxidizing to reducing conditions followed by replacement processes. Presence of microbial filaments may be due to the active role of microorganisms during the formation of these phosphatic nodules.

By Shamim A. Dar, Mohd Shuaib, K. F. Khan, Samsuddin Khan

The Late Paleocene–Middle Eocene phosphate nodules of Solan District of Himachal Pradesh belong to green facies of Subathu Formation of Sirmur group. Field observations indicate sporadic distribution of phosphatic nodules in the yellow brown to rusty brown, buff-colored bleach shales. Phosphatic nodules are dull earthy to dark grayish in color and break with sharp and conchoidal surfaces. Studies of phosphatic nodules using petrological microscope, X-ray diffractometry, and scanning electron microscopy (SEM) attached with energy dispersive X-ray (EDX) reveal that cryptocrystalline apatite (fluorapatite) is the dominant phosphate mineral. Silt sized silica is the dominant gangue, whereas pyrite and muscovite are present as minor gangue. The phosphate minerals occur as oolites, pellets, and cryptocrystalline apatite in the groundmass. Silica veins form a network replacing the original phosphatic matrix. Brown to brownish black color may be attributed by the organic matter in the phosphatic nodules. Completely phosphatized radiolaria and partially pyritized planktonic foraminifera are observed. There is corroboration of organic matter in the form of microbial filaments in the groundmass of apatite. The findings in the present investigation indicate that the different forms of the minerals, their texture, and distribution in the phosphatic nodules might be due to environmental vicissitudes in oxidizing to reducing conditions followed by replacement processes. Presence of microbial filaments may be due to the active role of microorganisms during the formation of these phosphatic nodules.

By H. H. Storch

"INTRODUCTION The first paper of this series contained data concerning the behavior of polyhalite (K2S04.MgS04.2CaS04.2H20) upon calcination and subsequent leaching with water at 100° C. It was found that upon heating polyhalite to temperatures between 298 and 500° C. the water of crystallization is driven off, leaving, an amorphous mixture of K2S04, MgS04, and CaS04. Two transition points were located; one at 298° C. which coincides with the vigorous evolution of steam; and one at 551° C. which results in the formation of a hard mass of crystals. The latter probably consist of a solid solution If the compounds langbeinite (K2504, 2MgS04), potassium dicalcium sulphate (K2304. 2CaS04), and anhydrite (CaS04). The heat of decomposition of polyhalite at 298° C. was measured and found to be 66,000 ± 5,000 calories per mol. The optimum temperature of calcination with regard to subsequent extrac¬tion with two parts of water (at "" 0° C.) is 430 to 450° C. for 65 to 100 mesh material, if one half hour at the calcination temperature is allowed. The maximum concentration of K2S04 obtainable in the extraction of calcined polyhalite is 11.4 grams per 100 grams of water. This concentration of K2304 is considerably above the equilibrium value (3.6 g. per 100 L. of H20 at 83° C.) with respect to the solid phases polyhalite, potassium calcium pentasulphate, ¬and anhydrite. The figure 11.4 K. of K2804 per 100 g. of H20 is also somewhat than the equilibrium value (9,65 g. per 100 g, H20) with respect to the solid phases potassium calcium pentasulphate and syngenite."

Oct 1, 1930

By R. A. Plumbridge

The Honourable Mr Molefe, Premier of the North- West Province; Or Scot-Russel, Chairman of the CMMI's XV Congress; Mr Loton, Chairman of the CMMI; distinguished guests, ladies and gentlemen. At the outset may I express my sincere appreciation to the organisers of this Congress for their kind invitation to me to participate in the plenary session. May I also thank the CMMI for inviting me to be their fifth distinguished lecturer. This is a signal honour and one which is sincerely appreciated by my Group and myself. The subject of gold is a very emotive one. It conjures up different images in the minds of a wide variety of people. For many of us it is very simply the ultimate metal. In ancient times gold was sought after and treasured; it was the chosen metal for adornment and many of the best preserved artefacts of that time were hand-fashioned from gold which had been won by primitive mining techniques. Gold's rarity and its value was recognised by those who fashioned the earliest gold coins thus underlining gold's special place as a store of value.

Jan 1, 1994

By Campbell Brown GA

IN 1904-5 diamond drilling operations in the Mount Morgan mine proved the presence of some inillioils of tons of rich, copper-gold ore, averaging about 45% to 50% silica and 22%Fe as sulphide. To smelt this ore in blast furnaces, without previous concentration, large quantities of basic flux.were required. Unlimited quantities of cheap, limestone, were available at Marmor, on the GladstoneRockhampton railway, 50 miles from Mount Morgan, but the supply of iron flux was a more difficult problem. Smelting operations started, with one' furnace in January, 1906, using as flux low-grade sulphide ore fro:m. the mine, containing very little silica. When the second, furnace was blown in this was supplemented by ironstone from, small aeposits in the immediate district. It was recognized that these sources of supply would be insufficient to keep the full plant going after the third furnace had been blown in. Accordingly, the deposits at Eabra and Mount Etna were opened, neither of which proved capable of supplying the quantity required viz, 1000 tons per week. Negotiations were meanwhile being conducted with the Marble Island Iron and Limestone Co. to obtain the right to mine at Iron Island, where a sufficiently large deposit was known to exist. Shipments from this source commenced in January, 1907, and ceased at the end of July of this year, when the metallic flux from...

Jan 1, 1912

By Tellis D. A

An outline is given of the general position of earthsciences information in Australia, the background to development of the Australian Earth Sciences Information System (AESIS) and the role of the Australian Mineral Foundation in developing and co-ordinating the projeot in co-operation with the CSIRO, BMR, National Library of Australia, AGIA, and many companies.Details 'of the system, method and anticipated rate of input (especially of unpublished material at which the System particularly aims), mode of dissemination, and use of the data base are discussed. Information on theAustralian Thesaurus of Earth Sciences and Related Terms and brief details of some 30 earth sciences information collections in Australia is given.

Jan 1, 1977