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By T. A. Lang

The objective was to develop a Program Plan of analytical studies and tests for determining (1) the optimum installation tension of a coal mine roof bolt, (2) the most valid bolt support theory or theories, and (3) the most valid roof failure theory or theories. On this basis a comprehensive literature search was made and significant material dealing with coal mine roof behavior, roof bolting and roof support was collected, reviewed, classified and analyzed. Emphasis was given to the influence of rock reinforcement on the control of deformation, stress field modification and mine roof stability. An assessment was made of the effect of various parameters including bolt tension, bolt pattern and time of installation, on the effectiveness of rock reinforcement systems, and equations developed for bolt tension as a function of these parameters, and rock properties. From these studies, a major program plan of tests and studies was developed for verifying and validating the most tenable theories of roof behavior and roof support and for determining optimum bolt installation tension.

Jan 1, 1979

By Leonardo Bravo, Leonardo Almeyda

En este artículo presentamos el caso de la unidad minera Cerro Lindo, en dónde se desarrolló e implementó una estrategia de control difusa que utilizó información sincrónica captada por sensores inteligentes y sensores virtuales para optimizar el proceso de molienda. La estrategia de control difusa se subdividió en dos etapas: (i) control de tonelaje de alimentación al molino y (ii) control de agua que ingresa al molino. Para regular la cantidad de mineral alimentado al molino de bolas se utilizaron las variables: (i) granulometría F80 del alimento medido de forma sincrónica y (ii) amperajes de las bombas de descarga. Una vez obtenido el tonelaje de alimentación, la lógica difusa calcula la cantidad de agua que debe dosificarse.

Sep 29, 2023

INTRODUCTION TO PROBABILITY THEORY The mathematical theory of probability provides the foundation for the interpretations and inferences that can be made from statistical techniques. Probability theory is a broad field of study in itself, and can only be touched on here in order to provide the necessary back- ground for a more complete understanding of statistical analysis. Probability is concerned with the outcome of random events. It had its beginnings in the theory of games of chance which were of great interest to European mathematicians during the last half of the 17th century. The outcome of a random process or experiment is defined as an event. The collection of all mathematical points associated with each event is called the sample space for an experiment. Consider a random experiment having a finite number, n, of possible outcomes, some of which have a characteristic A. What is the probability that A will result from a single

Jan 1, 1980

CHARLES E. WILSON'S second quarterly report "Meeting Defense Goals" was encouraging on the outlook for the mining industry, as prolonged demand for minerals seems assured; but for the individual engineer things are not so rosy. Ten percent of the gross national product is going for defense but the gross national product has been increased by 9 pct since the national emergency was declared apparently a commendable rate of progress. The increased production does not seem to have had the stabilizing effect on prices it should and housewives have been revising domestic budgets upward on a quarterly basis. Government economists have reached the conclusion that more taxes and wage and salary freezing are necessary to counteract inflation.

Jan 8, 1951

By O. Saeki

Dolomite-fluxed pellets have been produced at Kakogawa Works, Kobe Steel, Ltd., since August, 1975. The pellets contain 5.5 % dolomite and have a basicity (CaO/Si02) of 1.3. By charging 30-50 % of dolomite-fluxed pellets into the two large blast furnaces at Kakogawa, a low fuel rate of 450 kg per ton of pellets has been achieved with better furnace permeability and gas utilization. Laboratory studies show that dolomite-fluxed pellets have excellent high temperature properties, and that their softening and melting-down temperatures are about 50°C higher than those of lime-fluxed pellets, and that reducibility at 1250°C is increased from 25 to 70 %.

Jan 1, 1977

By M. David

This paper addresses the problem of technological transfer in geostatistics. Expert systems have become popular in certain fields because the needs of the industry are not provided for by traditional concepts and systems of education. The explicit knowledge approach in developing expert systems is presented through two experiments. The first describes a dedicated system written in GOLDEN LISP and the second a shell, using INSIGHT2, which has more general applications. Using expert systems forces on the user a new approach to parameter definition, and as an example an original method for the research of any anisotropy axes is developed which might well be useful in traditional programming. Two examples of application to a coal and a gold deposit are given.

Jan 1, 1987

By J. Zwartendyk, A. Azis

Optimizing the public gains from the exploitation of mineral resources By Dr A. AZIS and Dr J. ZWARTENDYK Every nation must decide how it should exploit its mineral resources so as to contribute most to its national objectives. It is argued that the present value of the future corporate income tax flow derived.from mineral exploitation may serve as a useful indicator in moving toward a taxation policy that would contribute optimally toward the greatest public benefit. The future stream of corporate income taxes depends largely on the mineral endowment, consisting of deposits now being mined, known unmined deposits, and unknown deposits. Unknown deposits may be estimated by geological inference. Both known and unknown deposits can be categorized according to grade and size, and divided into economic and uneconomic deposits on the basis of certain prices, costs, rate of return and taxation levels. Computer simulations can be run of discounted cash flow models at various taxation levels to showthe impact of taxation changes on future tax revenues.

What is your assessment of the mining industry as we near the end of the 20th century? As it always has, the industry is continually changing. The recent rate of change has been hectic. Many mining-related commodities are selling at low prices. These include gold, silver, copper, coal and soda ash, to name a few. Lower prices place pres- sure on mining companies to increase efficiency through productivity, down- sizing or mergers. The short- term effect of this situation may adversely affect the individual SME member. But the long- term benefit is to build a stronger, more productive and internationally competitive mining industry. In addition, most of these metals and minerals have been historically cyclical in nature, and prices will rebound.

Jan 1, 1999

By Frederick C. Trutt

A guide to the development and utilization of an interactive mine-power-system fault program (Z-bus by algorithm) is presented. Theoretical foundations, as well as implementation considerations are discussed with respect to the mine-power system. Alternative Kron reduction techniques are presented along with a triangular-storage method for storage conservation. Program capabilities include the analysis of balanced and unbalanced (line-to-line, line-to-ground, and line-to-line-to-ground) fault situations using symmetrical component theory. To account for phase shifting in delta-wye transformers and zero-sequence network constructions, transformer and load configurations are specified by the user. The positive-and zero-sequence connections needed for network conformity are automatically constructed with the required impedances.

Jan 1, 1979

By John J. McCabe

INTRODUCTION Over the years, Congress has written into the Internal Revenue Code various provisions aimed at lessening at least one financial burden faced by taxpayers in the mining industry - the federal income tax burden. These provisions include the election to deduct exploration expenses, the election to defer deduction of development expenses, and the percentage depletion deduction. Careful tax planning from the very beginning of a mining venture is essential in taking maximum advantage of these tax benefits. A major decision to be made is the choice of organizational structure. (For a more detailed discussion of this subject, see McCabe, John J., "Developing Structures for Investments in Mineral Property," New York University Institute on Federal Taxation, 42 NYU 24, 1984). One such structure is the use of multiple corporations, with mining activities conducted by one corporation and nonmining activities, such as manufacturing, financing and administration, conducted by the other corporation. This technique, which will be discussed in detail below, can be particularly advantageous in delaying recapture of previously deducted exploration expenses and in maximizing depletion deductions. TAX BENEFITS IN MINING Exploration Subject to certain restrictions discussed below, exploration expenditures (i.e., expenditures paid or incurred during the taxable year for the purpose of ascertaining the existence, location, extent, or quality of any deposit of ore or other mineral, and paid or incurred before the beginning of the development state of the mine are deductible at the election of the taxpayer (Section 617(a)).* Were it not for this option, exploration expenditures would be required to be capitalized and recovered through depletion, after production begins. Exploration of a mineral deposit can be very costly and may not result in commercial production for some time. If the taxpayer has income to he offset by the deductions, a mining venture can usually be structured in such a way as to allow the offset of mining losses against the other income. With today's high interest rates, this election can be quite valuable in present value terms. Corporate and noncorporate taxpayers are subject to different restrictions on this tax benefit. Corporations may elect to deduct only 85 percent of eligible exploration expenditures (Section 291(b)). (The Tax Reform Act of 1984 reduced this to 80 percent effective for expenditures after December 31, 1984, in taxable years ending after such date). The remaining 15 percent (20 percent after December 31, 1984) is capitalized and recovered at the same rate as five-year ACRS property (Section 291(b)). Individual taxpayers are not subject to this 85 percent rule; however, any amount deducted in excess of ten-year straightline amortization is a tax preference item for individuals (Section 57(a)(5)). Individuals may avoid the tax preference by electing to capitalize exploration expenditures and amortize them over ten years (Section 58(i)). In order to prevent the taxpayer from, in effect, converting ordinary income into capital gain by selling property that has given rise to exploration expense deductions, the Code requires recapture of such deductions upon the occurrence of certain events (Section 617): 1. Upon disposition of the property, adjusted exploration expenditures are recaptured to the extent of gain realized on the disposition (Section 617(d)). 2. If the property is leased, the lessor is disallowed any depletion deduction until his adjusted exploration expenditures have been recaptured in the form of foregone depletion deductions (Section 617(c)).

Jan 1, 1985

By Kevin Whipkey

How is Improvement Being Achieved ? Section Equipment ?Mine Layout/Projections ? Work Schedule ? Maintenance ? Management

Jan 1, 2005

By B. B. Cox

Iraq, formerly called Mesopotamia in Asiatic Turkey, became a kingdom under British Mandate after the world war and is expected to gain its independence in 1932 when it enters the League of Nations. The kingdom is shown on Fig. 1 in its relations to neighboring countries, to the Mediterranean Sea and to the Persian Gulf. It is slightly smaller than the State of Texas with its capitol, Baghdad, inland about as far from the Persian Gulf as Breckinridge, Tex., is from the Houston Shipping Channel. The oil fields lie 180 to 225 miles north of Baghdad, or about as far as from Breckinridge to Oklahoma City, and about as far from the Mediterranean as Fort Worth is from Hobbs, N. M. A narrow-gage railway runs from Basra, the Persian Gulf port, to Baghdad. From there another narrow-gage runs into the Kurdish hills east of the Tigris to Kirkuk. A standard-gage, part of the old Berlin-Baghdad system, follows the west bank of the Tigris northward from Baghdad to Baiji, a village about 100 miles south of Mosul. No railway exists between Iraq and the Mediterranean, though the Anatolian Railways in southern Turkey come to within 50 miles of the Iraq frontier and 120 miles of Mosul. Surveys have been completed for a railway through British Mandates from Haifa to Baghdad as well as for a railway through French Mandated Syria from Tripoli to Abu Kemal near the Iraq border. Wagon roads, excepting those constructed by the oil companies, are few and indifferent in Iraq and no road exists across the desert to the Mediterranean, but contrary to prevalent beliefs the surface is firm and free from sand dunes so that motor cars can go almost anywhere in dry weather, with ease. Frequent motor car and airplane service exists between Baghdad and the Mediterranean ports and motor car service may be had between Kirkuk and Nisibin, Turkey, where on two days each week through Wagons Lits service is available to Paris. Baghdad is about 21 days distant from New York City with present transport facilities. The climate is semiarid, similar to Imperial Valley, California, the average rainfall outside the mountainous parts amounting generally to

Jan 1, 1932

By S. W. Parr, T. E. Layng

The low-temperature carbonization of coal involves the carrying out of the coking process under conditions wherein neither the coal mass nor any of the passageways through which the volatile products pass are heated above 700" or 800" C. For convenience in this discussion, the single number 750" will be used to designate the maximum range. This temperature is not selected arbitrarily; it is the result of certain natural conditions that are inherent in the substances involved. Two of these conditions arc sufficiently pronounced to suggest a line of demarcation at this point as follows: (1) Below 750°, all the heavy hydrocarbons are expelled, which means that, at these lower temperatures, the illuminants, the gases of high calorific value, and the condensible oils are discharged; above 750") there are given off the lean, non-illuminating gases consisting for the most part of hydrogen and marsh gas and having no condensible constituents present. (2) Below 750") there is substantially no secondary decomposition; above 750") the volatile products are readily decomposed, forming tars, naphthalene, free carbon, etc. It is not intended to maintain that no secondary decompositions occur below 750". Many recent studies have demonstrated the practicability, especially in the presence of catalytic substances, of cracking certain of the hydrocarbon compounds; but at these lower temperatures the step is a moderate one, as, for- example, from xylene to toluene or from toluene to an anthracene. These changes are moderate in amount. Not only do the reactions proceed slowly but they are subjected to the decomposing . conditions for only a short time. This is evident when it is recalled that at these initial temperatures the decomposition of the coal is very rapid and, if anywhere near a neutral pressure is maintained, the movement of the evolved gases is lively and reduces, correspondingly, the time for the retention of the gases in the passageways where these milder decomposing conditions exist. It is acknowledged that the maintenance of these temperature conditions at the present time has only an ideal and not a practical status. Actual operations under these conditions, as a? industrial accomplish-

Jan 1, 1920

By Doug Williams, Kent J. McGrew, Dr. Jack Murphy

For some time, selenate has eluded water treatment by conven­tional means such as precipitation and clarification. This has been due to the nearly universal solubility of all oxidized sele­nium species, the low levels required for surface discharge, and almost identical chemical behavior to all forms of oxidized sul­fur. The last characteristic makes selenate particularly difficult to deal with in acid mine waters where sulfate can easily be on the order of one gram per liter. Approaches such as ion exchange or reverse osmosis often tum into total demineraliza­tion schemes for the sake of removing a "trace" selenium species that may be present on the order of 108 sulfate/selenate. Reduction of selenate to selenite or elemental selenium by chemical means has been relatively unresearched. Some limit­ed success has been reported (Murphy, 1988) using ferrous hydroxide as a reducing agent; however, the reaction time as reported is too slow to be useful in a practical plant design. One significant difference between selenate and sulfate is that selenate has been discovered to be reducible in acid solution by elemental iron when catalyzed by soluble copper. Since the +4 or zero valence states of selenium are rather easy to deal with by coprecipitation with iron salts or alum, the elemental iron dis­solved in the process contributes to the overall process by pro­viding sludge upon raising the pH that can be separated by con­ventional clarification. Commercial production of selenium using copper catalyzed reduction of selenite to selenium metal via sulfur dioxide is well established, however, at the < 5 ppb requirements for surface discharge this reduction process equili­brates at levels far too high to be useful to low level selenate removal criteria. The reaction reported herein uses elemental iron for reduction of selenate with copper acting either as a cata­lyst or as a coprecipitation agent. This method, employed with conventional sludging, clarification and filtration can provide an economic method to achieve non detectable selenium (< 0.005 mg/I). Iron consumptions for the conditions tested have been on the order of 3 lbs/1,000 gallons treated. This represents as little as $0.06 or $2.00 per 1,000 gallons based on using a scrap source of iron or the purchase of electrolytic iron for the process.

Jan 1, 1996

By A. J. Getz

Major precious metals projects are underway in Australia, Papua New Guinea, Indonesia, the Philippines and New Zealand. This article reviews the status of those projects. Included in this review are project location, reserves, method of resource exploitation, anticipated production, and other unique conditions. The article is limited to major precious metals projects in the Western Pacific region. This is not meant to negate the attractiveness or importance of the many other projects in that area. The geographical setting of these five countries are shown in [Fig. 1]. The gold output of the countries has increased dramatically during the 1980s. [Table 1] compares 1980 and 1988 production figures. The compound growth rate is 120%. That reflects the attractiveness of the region’s resource base as well as the impact of price increases, new exploration models and processing technologies, and changes in government policies. If the 10 projects discussed here are all brought onstream, their combined output - at about 130 t (4.17 million oz) - would amount to an increase of greater than 50% over 1988 production from this region. Table 2 shows indicative production levels for each of the 10 projects. Dollar amounts are in US currency unless otherwise specified. Australian dollars have been converted to US dollars at the rate of 1.28: 1.00.

Jan 1, 1990

Technology is playing an increasingly large role in the operations of our mines. There is a temptation to regard the implementation of technological systems as the objective itself when, in reality, systems are used to support a business process. Only when the process succeeds will the systems be seen to succeed. Understanding the distinction between system and process is critical. This understanding, together with the resultant holistic approach, is considered to be critical to successful implementation and operation of Mine Control process. This paper examines the critical factors essential to success in establishing and sustaining a Mine Control process that maximises benefits to an operation. These factors have been developed during the author&apos;s experience of nearly 30 years in Mine Control projects across over 50 sites. Each factor is discussed in relation to real world examples at well-known mines.

May 1, 2010

By Frances Badelow

This paper describes a design process for piled raft foundations supporting high-rise buildings. The design process comprises an initial stage of geotechnical site characterization using the results of investigation boreholes to prepare a subsurface model and derive geotechnical parameters for raft and pile design from empirical correlations. Following this a preliminary analysis is undertaken using a combination of elastic theory and allowances for non linear behaviour of the piled raft system to assess the viability of such a foundation system and any potential advantages of a piled raft over conventional fully piled foundation systems. Finally, a detailed analysis is undertaken using the GARP8 computer program. Case studies where this design process has been successfully used to design a more efficient piled raft system that has resulted in significant cost and time savings compared to conventional bored pile foundation options are also described.

Jan 1, 2006

By E N. Isaev, L E. Levin

New data on the geology of the Late Jurassic to Holocene sediments cover of the World and associated mineral resources (oil, gas, ferromanganese nodules, ores of massive sulphides and other metals) have been compilled in the Atlas at scale 1:25,000,000 and 1:10,000,000. The work was performed by scientists from four Institutes of Russia (VNIIzarubezhgeologia, VNIIoceangeologia, Vernadsky Institute of Geochemistry and Analytical Chemistry of theRussian Academy of Sciences and Geological Institute of the Russian Academy of Sciences). The Atlas shows variation of thickness and formational composition of the large complexes (Upper Jurassic-Early Cretaceous, Upper Cretaceous Eocene, Oligocene-Neogene, Pliocene-Pleistocene), distribution of oil/gas and ore deposits in each complex, data of deepsea drilling (leg 1-130), &nbsp;thermo-pressure condition in the sedimentary basins within Circum-Pacific Rim.

Jan 1, 1995

By Stephen H. Chung, Kevin Atherton

The main purpose behind this preliminary study was the reduction of costs while maintaining productivity. Finding a way to achieve this balance without compromising controls on safety and quality of blasting results is of continual interest to the mining industry and of particular interest when ore of lower grade is being mined.

Jan 1, 1998

DuPont is a chemical and energy multi-national of approximately 90,000 employees. Often regarded as the world leader in injury reduction and process safety management, DuPont operate 140 manufacturing sites around the globe. Conoco is a wholly owed subsidiary of DuPont which is involved in oil, gas and coal exploration. &nbsp; Throughout this paper I will discuss DuPont statistics, developing a safety culture and training process as well as discussing possible short comings in the New Zealand safety focus. I will conclude with my recommended improvements and issues for New Zealand companies to focus on. &nbsp; It is very difficult to compare DuPont and New Zealand statistics through lack of compatibility in recording methods and my ability to interpret ACC&apos;s Injury Statistics. However through considering DuPont&apos;s statistics, and comparing them to your own companies or departments, you will agree they are indeed impressive. I hope that by discussing DuPont&apos;s safety philosophy, and possible shortfalls within New Zealand Legislation many of you will find ideas and inspiration which will help you to further reduce your own injury rates.

Jan 1, 1997