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This paper describes a plant built at The Broken Hill Associated Smelters, Port Pirie to sample lead sinter automatically. As the plant is still in the commissioning stage results on the precision and accuracy of the sampling are not yet available, but some of the difficulties experienced during commissioning are discussed.

Jan 1, 1976

By Moto Goto

Onahama Smelter of Onahama Smelting & Refining Co., Ltd. has two green- charge reverberatory furnaces; the old furnace was constructed in 1965 and the new one in 1973. This paper discusses the use of oxygen-oil burners in a green-charge reverberatory furnace and also compares the copper loss in slag between the two furnaces at Onahama Smelter. During the past ten years of operation, no shutdowns of the old furnace were necessary and the smelting capacity was increased by 25% by the use of two oxygen-oil burners. These burners are suitable for a green-charge reverberatory furnace to in- crease the smelting capacity without causing an increase of the exhaust gas volume and refractory erosion. After two years of operation of the old furnace, a bottom build-up in the charging zone of approximately 50 centimeters was experienced, and this build-up has stayed at this level since then. In 1973, a new additional reverberatory furnace was put into operation. Copper content in slag of the new furnace was lower by approximately 0.15% than that of the old one during the first several months after the start-up. Investigations were then made on the effect of the bottom conditions in the charging zone on the copper content in slag.

Jan 1, 1976

By L. C. Raymond

Valuations in the mineral industry differ from those of other enterprises because mines and oil wells have a definite life so cannot be considered a perpetuity. This requires that in any mineral-property evaluation the recovery of invested capital is necessary during the life of the property. Capital write-offs for nonextractive industries are assumed to be continuously plowed back to sustain the operation and produce yields on the capital invested. The extractive or mineral industry, however, generally attempts to return to the investor both interest and principal during the life of a property. Normally this is done currently and the dividend includes both items. Where the mineral property possesses large reserves and the life factor approximates a perpetuity, the return on investment is generally comparable to that of industrial stocks. The valuation of a mineral property, at best, is based on educated estimates and judgment factors. This is particularly true as it relates to estimating selling prices over a long term or assessing the quality of management. Also, it is possible to make various assumptions as to rapidity of working out the deposit, varying time for start-up of operations, varying earning rates, so as to obtain different results with the same basic facts. Thus it is not surprising that two engineers, irrespective of their abilities, may not agree exactly even when given the same facts, but their results should be close enough to be used in establishing a fair value for trading purposes. The valuation is no better than the source of basic data and the soundness of judgment factors. Fundamentally the basic principles of mineral valuation are similar for base metals, sulfur, oil, or any other mineral. Each mineral, however, requires an engineer to have a knowledge of such factors as its occurrence, distribution, mining and processing methods, and marketing problems in order to gather and analyze all the facts and data that have a bearing on the earning potential of the property. Present Value of a Mineral Property In essence the present value of a mineral property is a sum of money in today's dollars that future income from the property are worth. It differs from the total anticipated earnings by the amount of the interest that the unrecouped investment could be expected to earn during the period of recoupment. Thus, if one could accurately estimate what a mineral property will earn during its life, after deducting all operating, administrative, capital, interest, and tax charges, the determination of present value would be a relatively simple mathematical calculation. Normally, where the expected life of the mineral property extends beyond 20 or 25 years, the discounted value of earnings beyond this period is relatively small. The petroleum industry generally discounts the annual cash flow of an operation rather than earnings since, for tax-saving purposes, earnings are kept

Jan 1, 1976

By Kelly BJ, Smith GA

The recommendations of a recent American report on "Better contracting for Underground Construction" are considered in relation to Contracting practices on major Australian projects by representatives Of the "classical trilogy" - the Owner, Engineer and Contractor.

Jan 1, 1976

By Joseph D. Martinez

"The benefits of modern technology can readily be identified with energy availability. A clear correlation has been established between per-capita energy consumption and the GNP for various nations. The United States is an outstanding example of a nation which has benefited from vast energy reserves. The nation is now challenged, how¬ever, by dwindling reserves and the need to develop new sources consistent with the preservation of environmental quality. The development of new, virtually inexhaustible and environmentally acceptable sources cannot be expected for several decades. Meanwhile, we will have to depend on coal, nuclear energy and/or rigorous conservation measures.The net effect of environmental considerations has been to delay and perhaps ultimately eliminate the nuclear energy option as a national energy alternative. This forces a more positive move toward coal as the next major source of electrical power. Our coal resources are large, but the use and production of coal is also a threat to the environment. Thus, we seem to be moving from one major accessible source to another due to environmental concern only to face the probability that the alternative is also environ¬mentally unacceptable.Controversies revolving about energy choices must be resolved by an analysis of the relative benefits and impacts of these two sources and others. The pattern of changing energy sources is not new. We have moved from wood to coal to oil and gas in the past and must learn to adapt in the future. Rational decisions must be made relative to the utilization of intermediate energy sources pending development of promising future approaches. A collapse of current levels of energy supply could threaten our technological society and the means to develop a new energy base."

Jan 1, 1976

By John E. McCullough

The purpose of this development program is to design and develop a known volume air sampling pump for use in measuring the amount of radio-active material in the atmosphere of an underground uranium mine. The principle nuclear radiation hazard to underground uranium mines comes from the mine atmosphere. Daughter products of 222-radon, namely 214-polonium, 214-lead, 214-bismuth and 214-polonium, are inhaled by the miner, resulting in a relatively high lung cancer rate among these workers.

Jan 1, 1976

By Aarne Kopanen

In recent years, various renovations have been carried out in the production chain of the Outokumpu copper refinirg process. The anode casting shop, which is the final integral production section at the Harjavalta copper smelter built in its original form in 1945, was fourxl unsuitable for technical and capacity demads during longer periods of operation, and a new casting shop was built in 1974. The electrolytic copper refinery of Outokumpu Oy at Pori was built in 1941, and subsequently expanded in two stages. Even with its present limited scale of production it has been fom important to mechanize the main operations. This work was started in 1967 with the design and construction of the starting sheet machine connected with the cathode washing and unloading machine as a combined unit. Mechanized treatment of anodes has gained advantage particularly from the new design of a highly automated anode casting shop. In the further development of the mechanization a stripping machine for, starting sheets was designed and installed, starting operation in 1974.

Jan 1, 1976

By Charles M. Curtin

A significant advance in nonelectric delay blast initiation has been achieved by Nonel shock tube, an invention patented by Nitro Nobel AB of Gyttorp, Sweden. Ensign Bickford has been licensed by Nitro Nobel to manufacture Nonel in the United States.

Jan 1, 1976

By J. B. Cheung

The results of a program to demonstrate the technical feasibility of hydraulic borehole coal mining are presented in this report. The hydraulic borehole method of coal mining involves inserting a hydraulic mining device into a borehole that has been drilled from the surface into the underground coal bed. The borehole mining device issues a jet of water under high pressure, which breaks the coal. These pieces of coal, along with the water, form a slurry, which flows to the base of the borehole where it is pumped to the -surface. Phase I of the program encompassed the design, fabrication and factory-testing of a hydraulic borehole mining device. The program was successfully completed with the field tests being conducted at the Wilkeson-Carbonado Coal Field near Wilkeson, Washington. The technical feasibility of hydraulic borehole coal mining was demonstrated by mining 32 tons of coal at a depth of about 75 ft over a period of 4 hours.

Jan 1, 1976

By J. V. Calara, J. D. Miller

The sign of the surface potential for complex non-reactive ionic solids cannot be predicted solely from consideration of the hydration energy of gaseous ions which constitute the ionic lattice. Accurate analysis of these systems must involve the hydration energy of surface ions, which requires knowledge of the crystal structure, the identification of cleavage planes, and the calculation of binding energies of surface ions. Surface binding energies for ionic solids can be determined if the Surface Madelung Constant is known. A computational technique was developed for the calculation of Madelung Constants for infinite lattices which gives excellent agreement with the values calculated by other more complicated methods reported in the literature. Extension of this technique permits the calculation of Surface Madelung Constants and binding energies of surface ions, [Aus], for semi-infinite solids. The hydration free energy of gaseous ions, [AFh], together with the calculated binding energy of surface ions, [Aus], allows calculation of the hydration energy of surface ions,[AGh], as for the case of the ionic solid, MX: [ ]

Jan 1, 1976

By David E. Siskind

The Bureau of Mines studied environmental blast effects in six occupied residential structures. Airblast, ground, and structure vibrations were measured both inside and outside residences for seven quarry production blasts. Walls and floors responded to the blast noise and vibration by shaking at their own natural frequencies, often with greater peak particle velocities than the ground outside the structures or their foundations. The vibrations of the houses generated noticeable internal noise, correlating with the arrival of the groundborne energy. The later arriving airblast wave was predominantly at low infrasonic frequencies (1.0 to 1.5 Hz) and had similar amplitude and frequency characteristics both inside and out-side the structures. Significant structural motions resulted from the air-blast overpressures for at least two of the seven blasts. The most severe airblast effect occurred at a house 1,800 feet from a 5,047-pound (200-lb/ delay) blast. This stucture was subjected to a peak 0.16-in/sec particle velocity and 130 dB(L) airblast. The wall of the second floor responded to the ground vibration and airblast by shaking at particle velocities of 0.15 and 0.28 in/sec, respectively. Analysis of these data and those from additional field studies will be used to identify appropriate, safe, and reasonable impulsive noise levels, measurement techniques, and factors of design applicable to minimizing the adverse environmental effects of blasting.

Jan 1, 1976

By George C. Ference

Sulfur is the 13th most common element in the earth's crust, constituting approximately 0.05% of the total. It occurs naturally in its elemental form, as metallic sulfides, nonmetallic sulfates, and as combined or free sulfur in natural gas, crude oil, and coal. COMMERCIAL SOURCES Most of the sulfur that is consumed is converted into sulfuric acid before use; therefore, it is not necessary to recover sulfur solely in its elemental form. Processes for recovery are peculiar- to the types of reserves being processed. The major commercial processes as well as the general geographic locations where the appropriate reserves occur are listed in the following. It should be noted that the sulfur values may be recovered as the primary product, as a coproduct with other materials, or as a byproduct. Elemental Sulfur 1) Frasch mining is used for subterranean deposits of elemental sulfur around the Gulf Coast areas of the United States and Mexico. Generally, but not exclusively, such deposits are located in salt dome structure. 2) Autoclaving, flotation, or solvent extraction of surface deposits of elemental sulfur is practiced throughout the world. 3) Extraction and conversion of hydrogen sulfide from sour natural gas into elemental sulfur is done principally in Canada, France, and the United States. 4) Conversion of metallic sulfides from pyrites into elemental sulfur is done via the Outokumpu process in Finland. 5) Catalytic cracking and hydrocracking of sulfur-bearing crude oils to produce elemental sulfur is done worldwide. Desulfurization of refined petroleum products also yields elemental sulfur. 6) Recovery of elemental sulfur from sulfur-bearing oil sands (Athabasca tar sands) has been initiated in Canada. 7) As of this writing (1970), a plant has been constructed for the thermal decomposition of gypsum to produce elemental sulfur in the United States. Sulfuric Acid Sulfur values in the form of sulfuric acid are recovered via: 1) Recovery from smelter gases throughout the world. 2) Roasting of pyrites throughout the world with iron sinters as a byproduct. 3) Roasting of anhydrite with cement as a coproduct, primarily in Europe. 4) Processes currently are being developed for recovery of sulfuric acid from combustion gases resulting from the burning of high-sulfur-content fuel. Other Sulfur values also are recovered from waste products which normally occur in highly industrialized areas. Some examples are: coke-oven gases, sludge sulfuric acid, and pickling liquors (ferrous sulfate).

Jan 1, 1976

This paper first describes the essentials of the slurry shield method and its achievements, then problems encountered during driving tunnels and their countermeasures, and finally shows problems to be solved in the future. The author works at Tekken Construction Co., Ltd. as a director. All the data cited are based on material gained from the slurry shield tunneling works undertaken by the said company. The mark, viz*, indicates that Tekken Construction Co., Ltd. has obtained or is applying for a patent in the U.S., Europe and Japan. 1. CONSTRUCTION RECORDS BY SLURRY SHIELD METHOD AND ITS PROBLEMS (1) Shield machines in the future should have the following characteristics; a. to be able to drive less cohesive soil b. to make no change to the ground water table level c. to make it possible to let people work in normal air pressure d. to cause less settlement at the surface To meet the above conditions various kinds of mechanical shields have been are tried, viz. limited air pressure type, rotary cutter with slit regulator, screw-discharge type, blind shield, etc. As far as the author knows, however, they are not 100% successful. Tunnels need their own accuracy in accordance to the usage. Both ease of driving

Jan 1, 1976

By Wm. Ross Wayment, Innes P. Grantmyre

INTRODUCTION It has been recognized for some time that major changes in mining methods will be required in the near future. Two types of factors contribute to this need for change. Intrinsic factors include ground control problems associated with mining at increasing depths, noise, dust, toxic fumes, and logistics problems which arise from operation in a cyclical fashion. Extrinsic factors include competition for labor from industries offering safer and less difficult work, pressure for less impact on the environment, and changing economic and political conditions. The search for new mining methods has resulted in extensive research being carried out on such novel approaches as thermal fragmentation, high-pressure water jets, sonic drilling, microwave fragmentation, and laser cutting, among others. Joy Manufacturing Co. has elected to concentrate on impact breaking in stopes as a first generation continuous hard rock miner. IMPACT BREAKING Fragmentation techniques show a drop in specific energy as efficiency improves. Specific energy is the energy consumed per unit volume of rock removed and is affected by such variables as rock material properties, fragmentation method used, operator skill, tool design, etc. Mechanical fragmentation methods generally have specific energies much lower than that of the more novel methods. Table 1 shows impact breaking to have an efficiency exceeded only by that of drill and blast methods and it is this high efficiency which led Joy to impactors as the subject for research on potential mechanisms for continuous mining in hard rock.

Jan 1, 1976

By Thomas A. Lang, Kanwarjit S. Chawla, Francis S. Kendorski

Unlined water tunnels have often been used as pressure conduits for hydroelectric projects. However, fallouts of rock in such tunnels are not uncommon and in many cases have been attributed to erosion of shears and seams. A case history of such a fallout is described. An appraisal of the conditions pertaining to the fallout led to the conclusion that rapid changes in the water pressure in the tunnel resulting from operating conditions were significant factors in initiating the fallout. Other factors that contributed to the fallout are also described.

Jan 1, 1976

By Richard L. Gordon

Minerals long have been important commodities in international trade. As an inevitable result, the governments of the world have employed a wide variety of programs that affect the flow of trade. Roughly speaking, we may distinguish between the desire of more developed countries (MDCs) like the United States, western Europe, and Japan to control imports of minerals and the concern of less developed countries (LDCs), like India, about exploiting and exporting their minerals. The terminology used to describe different countries and the classification of specific countries into groups is unsettled and often changing. The poorest countries have been characterized as backward, undeveloped, underdeveloped, and developing. The problem seems to be in selecting a term that is both accurate and polite. Less developed seems, for reasons outlined by Hagen [pp. 51-57], the most convenient term. The borderline between an LDC and an MDC is always open to dispute. Objective measures are difficult to develop because of deficiencies in basic data, and enormous conceptual problems arise in making valid comparisons from even good data [see Hagen, pp. 7-28]. Thus, policies of the MDCs can be evaluated chiefly by using a few basic arguments for protectionist attitudes towards international trade. In dealing with the LDCs, a more far-ranging evaluation that covers general economic policy goals, the role of foreign investment, and the indirect effects of trade is required. This duality breaks down when trying to deal with the depressed areas in an MDC; here the issues are more akin to those associated with problems in an LDC. Similarly, variants of arguments used in LDCs appear in debates about foreign investments in MDCs. The whole discussion of minerals in LDCs, moreover, has obvious implications for MDCs like Canada and Australia. They, too, must face problems about the best utilization of their resources. THE RESTRICTION OF MINERAL TRADE BY DEVELOPED COUNTRIES[a] At least to some extent, the world's leading industrial nations have intervened to control the inflow of minerals. Such regulation is particularly pronounced for energy. Both the United States and western Europe employ

Jan 1, 1976

By Joan T. May

The Bureau of Mines conducted laboratory tests to evaluate the production of high-purity H3P04 by HCl digestion and solvent extraction. Both batch and bench-scale continuous tests were made. Western phosphate rock concentrates were acidulated with HCI, and the digestion liquors were processed by solvent extraction. Phosphoric acid was extracted with isoamyl alcohol and recovered from the organic extract by contact with an NH4F solution. This solution was fractionally distilled to yield high-purity H3P04. The raffinate from solvent extraction was treated with lime to precipitate CaF2, which was subjected to steam pyrolysis to generate HF. This method was successful in recovering 95 pet of the phosphate and 80 pct of the fluoride contained in the concentrates.

Jan 1, 1976

By H. H. Fields

The Bureau of Mines conducted research to determine the effectiveness of long holes drilled in solid virgin coal in degasifying an area of the Pittsburgh coalbed showing that horizontal holes drilled into a virgin coalbed from the bottom of any shaft will effectively remove methane gas in commercial quantities from the Pittsburgh coalbed. The in situ pressure at a depth of 214 feet into the coalbed and the average gas and water flows from the five degasification holes were 3 lb/in2 gage and 860,000 ft3/d and 1.7 gal/min, respectively. On June 19, 1975, after 593 days of degasification, a compressor was installed and pipeline quality gas was introduced into a commercial pipeline. As of June 1, 1976, after 1,022 days of degasification, over 753 million cubic feet of gas had been drained and 117 million cubic feet of gas had been purchased by the gas company for use in the local community of Wadestown, W. Va. The gas drained to date is six times the gas estimated to be in the area subtended by the holes. Methane emissions at the working face of 1 West mains, Federal No.2 mine has been reduced by 50 pct, proving the value of methane drainage by horizontal degasification holes drilled from shaft bottoms ahead of mining.

Jan 1, 1976

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

6. Computer Simulation of Mine Evacuation Analysis of mine evacuation involves manipulating a large number of interacting variables, such as mine passages, hoist movements, miner position etc. , which makes the problem very difficult to solve without use of a digital computer. Therefore, under this contract, a computer program is written to simulate evacuation of a mine under different configurations. The simulation input variables include characteristics of the mine, expressed in the form of a network of passages, properties of hoists and hoisting strategies, initial miner positions, ventilation and compressed air velocities, stench warning system and self-rescuer capabilities. The simulation can be carried out for cases in which there is no fire, i. e , fire drill simulation, or for cases in which there is a fire at any arbitrary location. The fire is assumed to generate gases which impede movement of miners in the gaseous region. However, the thermal effect of the fire on ventilation or on the miners is not considered. The simulation output includes the evacuation time for each miner, movement of the hoists, propagation of smoke through the mine passages and smoke exposure time of the miners. Details of the mine evacuation program are summarized in Appendices A and B Appendix A describes structure of the program and its capabilities. The flexibility of the program and its suggested uses are demostrated by a number of illustrative examples Appendix B is a user' s manual for the program which includes instructions for program use and explanation of the logic employed in the program. A computer listing and printout of a typical output are also included in the Appendix B The ten illustrative examples summarized in Section A 4 (Appendix A) provide proof of validity of the program and help make certain inferences about mine evacuation. The first example, which is simulation of an actual mine fire drill conducted in a mine, has predicted evacuation time within 5 percent of the actual evacuation time in the fire drill, demonstrating thereby, the ability of the program to make accurate predictions.

Jan 1, 1976

By W. P. Diamond

It is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Ala. Most of this methane will be encountered by mining. Coals of the Mary Lee group are presently being mined at depths exceeding 1,000 feet and will in the near future be mined at even greater depths, where the problem of methane gas affecting the mining operations will be acute. It is calculated that approximately 90 pct of the methane is at depths greater than 1,000 feet, and over half of the gas is contained within only 12 pct of the study area which is under more than 1,500 feet of over-burden. Degasification in advance of mining will increase mine safety, reduce ventilation expenditures, increase productivity, provide an additional energy source, and make it possible to mine parts of deep coalbeds that probably could not otherwise be mined.

Jan 1, 1976