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By G. H. K. Schenck, H. W. Robinson

Private weather forecasting services available on a contract basis can significantly reduce the uncertainty associated with weather-induced changes in mineral production and demand. Such services offer the mineral producer the opportunity for tactical and strategic response to weather conditions. There are at least 50 private meteorological consulting services as well as numerous individual meteorology consultants. Fees for services range from $150-$600 per day for one man to over $20,000 per month where a complex forecasting or modification program is undertaken.

Jan 1, 1971

By N. V. Melnikov, L. N. Marchenko

The latest theoretical and experimental study of physical processes initiated by explosions in solid media have made it possible to obtain a deeper insight into the mechanism of the energy transfer to ambient rock from char es of explosives interspersed with various air gaps. As shown in (17, high explosive action causes excessive fragmentation of medium in the vicinity of the charge, while expansion of the process into the massif is negligible. A theoretical outline of a more rational application of explosion energy was given with a view of obtaining more uniform fragmentation of rock convenient for loading and transportation. The proposed idea proven by experimental study consisted of the possibility of explosion control based on redistribution of explosion energy. Practical realization of the above idea was proposed (1) involving charges with air gaps for rock fragmentation. Since the Rolla Symposium on Mining Research (USA, 1961) (2), borehole charges with air gaps have become common practice. This method of rock blasting is applied in open cast and underground mines working the hardest and viscous, hard, medium hard and soft rocks (ore, quartzites, granites, 1 imes tones, sandstones, coals, etc.) as well as at enterprises for extraction of building materials and raw chemical minerals of any strength. Application of charges with air gaps results in an increase of the degree and uniformity of fragmentation (up to 94 percent of the blasted rock mass consists of fragments not exceeding 400 mm), the average fragment size decreases by 1.5-2 times and the amount of lumps is reduced by 2-10 times (in some cases there are no lumps at all ). Besides, the amount of operation for filling boreholes with tamping material is reduced, the specific consumption of explosives

Jan 1, 1971

By Roberto Carranza

The planning of experiments and the importance of statistical interpretation of the results have been recognized for years by scientists and engineers. The Factorial Design of experiments is among the various methods used for this purpose and is being widely applied in all branches of research and production. The basic principles of this tool have been described in detail (1, 2, 3, 4) and several examples of its application in various fields have been published (5). In recent years the mineral industry has also used Factorial Design to improve the efficiency of research, testwork and plant operation (6, 7, 8, 9). This method permits for a qualitative determination of the influence of the variables studied in a process and also a qualitative measure of the interaction of the variables. By graphic means or derivative methods, one may also establish the optimum conditions of the process (ibid 7, 8, 9). It is desirable, however, to develop mathematical methods to evaluate quantitatively these effects and restrict the optimization to the practical limitations of the variables. It is also convenient to adopt a notation system to generalize the Factorial Design.

Jan 1, 1971

By Charles F. Herbert

In February of this year at the Washington, D.C., hearings of the Interior Department on the Alaska pipeline, the author was amazed to hear speaker after speaker oppose not only pipline construction but any development whatsoever in the State of Alaska. In one case, a man objected to development in Alaska because his neighbor in Maryland had cut down some shade trees. Another man recited at length from the poems of Robert W. Service. While it seemed inconceivable that such thoughtless opposition should have any effect, a check with the offices of some congressmen showed that mail was largely against any development of Alaska. In the barrage of words and redundant phrases directed against Alaska, it is difficult to find a thought worthy of study. Fortunately, there is a statutory guide towards resolution of the problem of development versus non- development. This law, the Environ- mental Protection Act of 1969, has indeed given much of industry the jitters; copper smelters see no way to comply with the new sulfur- emission standards, the Alaska Department of Highways estimates that the Act has nearly doubled the cost of planning and engineering for highway construction. In spite of these and many other troubles and costs, the Act provides a sound legal basis for defeating nihilistic emotions and, since Alaska is relatively undeveloped, adoption of environmental safeguards will be simpler than correcting longstanding abuses.

Jan 1, 1971

By E. J. White

Data from oil well logs and core analyses were used to quantitatively evaluate formation porosity and water saturation of heterogeneous carbonates and to study the pore geometry and performance characteristics of cores from these formations. Logs and cores from the Madison limestone from 233 wells in three fields in the Williston basin were used in the investigation. A comparison of log and core analyses shows that log porosities are consistently larger than core porosities, and the differences are correlatable with core porosity ranges. Water saturations from logs are usually smaller than the corresponding core saturations by summation of fluids, but the difference is attributable to mud filtrate invasion into the cores during drilling. Petrophysical studies show that the low permeabilities and high residual water saturations in these reservoir rocks are due to their fine crystalline texture and complex pore geometry (heterogeneity). It is concluded that both log and core analyses must be used for reliable evaluation of these carbonate formations.

Jan 1, 1971

By Roberto L. Romero

The dressing of Bolivian tin ores has been done up to the present by classical. gravity methods, taking advantage of the high specific gravity of cassiterite compared with that of the accompanying gangue. For this purpose, jigs and shaking tables are used in the treatment of the various size fractions in which the ore is classified. Bolivian ores are mainly of the vein type and, to obtain a reasonable separation, crushing and several stages of grinding are necessary during the process to substantially liberate the cassiterite from the gangue. Gravity processes for cassiterite are effective for sizes down to 200 mesh. Below this size the efficiency of the gravity methods falls off very rapidly with increasing fineness of the mineral grains. The conventional treatment for this material is desliming followed by tabling on shaking tables various other types of machines have been designed for the gravity treatment of these fine particles but they have had limited success. Bolivian ores contain an appreciable amount of minus 200 mesh material constituted by "primary fines" caning from the mine itself, and "secondary fines" originated during the crushing and grinding necessary for liberation of the difficulty in the treatment of these fine particles is one of the causes why the recovery of tin in concentrates is only of around 50% in the mines owned by Corporacidn Minera de Bolivia, the State owned enterprise. The average figure for other Bolivian mines is

Jan 1, 1971

The metallurgical works of the Electrolytic Zinc Company is situated on the Derwent Estuary, approximately five miles north of the city of Hobart and near a relatively dense housing area. Zinc concentrates, consisting chiefly of zinc and sulphur, have been roasted at Risdon for 53 years;- recently at rates of 1, 100 tons per day. The zinc content of the ores is converted to zinc calcine (ZnO), which is a dusty material. The calcine is leached with acid to form zinc sulphate, which is then electrolysed to make zinc. The sulphur is oxidised during roasting to sulphur dioxide, part of which is converted to sulphuric acid and part is dissolved in estuarine water which is then discharged to the Derwent Estuary. Photographic slides were exhibited showing the unaffected green flora of the nearby hills, of clear exit stacks, of green lawns, and of a w ll lrcnt nines hnlP anlf nniir.qa within the Wnrka hnnnrla_rv_

Jan 1, 1971

By Thomas J. Crocker, Galen G. Waddell, Eugene H. Skinner

This paper describes a method of measuring initial and long-term deformations which occur in the medium surrounding mine accessways, and discusses the importance of this type of measurement in assessing support-problem areas. Delineated are (1) description of the rock-deformation monitoring equipment, (2) results of two field tests which monitored rock deformation around 4-foot-diameter raise bores, and (3) a numerical-analysis (finite-element) technique to correlate theoretical with experimental results. Instrumentation developed provided the sensitivity and resolution needed to measure rock deformation around a full-scale raise bore during excavation. Results of the tests conducted at the Lucky Friday mine, Mullan, Idaho, show the relationships between (a) de- formation vs. time, and (b) deformation vs. bit progress. Based on theoretical evaluation of the initial deformation, the medium appeared to behave elastically. Using an estimated field stress of 5,500 psi and Poisson's ratio of 0.20, the gross modulus of elasticity of the rock was calculated to range from 3.15 to 6.0 x 106 psi (with one outlier which was determined to be >12 x l06 psi).

Jan 1, 1971

By A. Leppala

Scope of the Courier 300 System The fact that reliable on-stream analysis is a prerequisite for effective flotation control is hardly disputed today. Nevertheless, up to now no system has been available that includes all the equipment necessary for successful analysis. However essential an on-stream analyser is in itself, reliable and accurate assaying can only be assured after techniques for sampling, handling the slurries and computing the X-ray data have been developed for the purpose. The Outokumpu Company's Courier 300 System is a complete package that can be installed and handed over with the key. It includes the equipment needed for sampling and handling the slurries. It has been developed from the start to meet industrial demands. Obviously an on-line system must comply with far stricter standards than one designed for a laboratory. Assays are computed by an Outokumpu 316 digital data processor, which is an integral part of the system and controls its entire performance. The computer software is programmed as a standard package, including a highly advanced new model for assay computation. Analysis output is available for a process computer, report typewriter:, and recorders. The package also includes calibration for slurry assays at our pilot installation before delivery. A complete Courier System can analyse up to 4Z slurries and six elements in each slurry. Thanks to its modular design, it can be dimensioned initially to the customer's requirements and is easy to expand later at low cost. Being a mining company itself, Outokumpu has been able to utilize its own long experience in non-ferrous metallurgy - an important factor contributing to the success of the Courier system. History of the project and present installations The first on-stream analyser was installed at Outokumpu'a Pyhasalmi Con¬centrator at the end of 1967, after several years' development. Since then,

Jan 1, 1971

By Foster Fraas

Calculations based on data related to the electrostatic precipitator illustrate the variation in the electric forces on a particle with change in position in the ionized field. The feeble forces in some separators are explained by the low field intensity at midpoint locations between the electrodes. When the particles are in contact with the exterior surface of a rotating cylindrical electrode, a high field intensity at the electrode surface combined with the image charge results in large electric forces. The permissible feed velocity increases as the square root of the electrode diameter, providing high values in efficiency and feed rate capacity, particularly in surface-to-mass ratio separations such as are encountered in secondary materials recycling operations.

Jan 1, 1971

By R. Walker

This paper deals with the selection and design of a belt conveyor handling steam coal between a mine and a barge loading terminal, and extending for some 5 ¼ miles over some of the most rugged terrain in the state of West Virginia, U.S.A. After a thorough analysis by consulting engineers and the owner's engineers, a single-flight cablebelt conveyor was chosen as representing the alternative of greatest reliability and lowest over-all cost. The value analysis and design features of the system are covered in this paper along with an updated report on the performance of the system since its start-up in the spring of 1969.

Jan 1, 1971

By Warren B. Davis

Introduction If a subject this broad were to be covered in even moderate detail, it would require a set of books about the size of an encyclopedia. Since an acceptable length for this paper is a small fraction of one book, it will have to consist of a few samples of the subjects that I think are the most pertinent to World Fossil Fuel Economics. I plan to discuss the trends in world energy demand, particularly in the U. S. and Europe; the consumption patterns and cost patterns of oil, gas and coal; the prospects of synthetics; and some of the effects of government regulation of fuel economics. World Energy Demands Fig. 1 shows Free World energy consumption by principal areas for the period from 1950 to 1970 and a forecast for the period from 1970 to 1985. These figures include only the measurable forms of energy. An example of energy consumption that is not measured is the wood a peasant might cut in the forest and bum in a fireplace to heat his home. This omission probably is a very small part of the total. This forecast is not identical with that of Wayne E. Glenn (see Page 22), but the differences in total energy consumption are not significant. The U. S. consumption, which was 55 percent of the world total in 1950, had declined to 45 percent by 1970, and is expected to decline further to 38 percent by 1985. Western Europe has consumed 28 percent of the total from 1950 to 1970 and is expected to lose share slightly between 1970 and 1985. The most spectacular gainer is Japan, which increased consumption from 2.5 percent in 1950 to 7.5 percent in 1970, and is expected to reach nearly 17 percent by 1985. The over-all Free World total has grown from 62 quadrillion Btu (equivalent to 29 million B/D of crude oil) in 1950 to 151 quadrillion by 1970, an average growth rate of 4.5 percent/year. This total is expected to grow at a rate of 5 percent/year between now and 1985, reaching 315 quadrillion Btu (equivalent to nearly 150 million B/D). Fig. 2 shows which fuels supplied this energy between 1950 and 1970, and gives an estimate of how it will be supplied between 1970 and 1985.

Jan 1, 1971

By Benton L. Tibbetts

Comprehensive geophysical measurements were made in the Tertiary Channel gravel deposits of Badger Hill, Calif., with the refraction seismograph, gravimeter, and well logging equipment, to develop a three-dimensional physical model of the gold-bearing gravels. Tests were also made of the applicability of magnetometer and electrical resistivity techniques. Results of 14 seismic profiles revealed four distinct layers with velocities of 1,600 ft/sec for loose gravel, 5,900 ft/sec for compact gravel, 8,600 ft/sec for cemented, blue gravel, and 15,500 ft/sec for bedrock. The depth to bedrock along the middle of the channel varied from a minimum of 100 feet in the hydraulically mined pit area to a maximum of about 300 feet in the upper bench area immediately south of the pit. These geophysical methods revealed that 40 percent of the drill holes necessary to delineate the deposit could be eliminated, at a cost saving of at least 30 percent.

Jan 1, 1971

By Alfred Weiss

The business world of tomorrow will experience a major change in its data communication systems, with the mineral industry being among those to feel the greatest impact of this change. This development can be expected to occur over the next two decades at a steadily increasing tempo. One major factor prompting this transformation is the fact that technological knowledge is doubling approximately every five years. Moreover, industry is becoming more and more dependent upon the flow and processing of information in its long-range planning, while government requirements and regulations demand increasingly detailed and precise information on plant operations.

Jan 1, 1971

By Thomas L. Craig

The Wellman-Lord SO2 Recovery Process is operating commercially at one location in this country and at two locations in Japan. Tail gases from a sulfuric acid plant, from an oil fired steam generator and from a sulfur recovery unit are the respective applications. 1) At the Olin Corporation's Paulsboro, New Jersey, stack gas from a spent acid regenerative sulfuric acid plant-45000 SCFM - is treated in the W-L unit to reduce sulfur dioxide concentrations from 4500 ppm to less than 500 ppm. 2) At the Japan Synthetic Rubber plant in Chiba Prefecture, stack gas from an oil-fired steam generating plant - 120,000 SUM - is reduced from 2100 ppm S02 to less than 200 ppm. 3) At the Toa Nenryo Kogyo refinery in Kanagawa Prefecture, tail gas from a sulfur recovery (Claus) unit - 41,000 SUM - with, an inlet SO2 concentration of up to 13000 ppm is reduced to less than 200 ppm. The three installations are operating successfully and are capable of reducing S02 emissions to levels significantly below the concentration guaranteed. With the one exception of a higher than guaranteed chemical make up requirement at Paulsboro, utility and chemical requirements will be less than design.

Jan 1, 1971

By M. D. Schlesinger

Mercury exists in coal at very low levels; the structure of coal, the vapor pressure of mercury, and its almost universal occurrence introduce unusual problems into the analytical methods. Round-robin analyses by several laboratories, each using its own techniques, indicate that the average mercury content of coal is about 0.2 part per million. Some western coals are as low as 0.05 ppm.

Jan 1, 1971

By John C. Cook

A 1-year program of exploratory research, to determine the feasibility of radar exploration in advance of coal mining, has been completed. Advance detection of obstructions including faults, clay veins, abandoned wells, and pyritic concretions would improve the safety and efficiency of mining. Initial calculations based on laboratory tests of the RF electrical properties of bituminous coals indicated feasibility; radar waves at frequencies below 100 MHz should be detectable through tens to hundreds of meters of coal and be well-reflected by clay, pyrite and metal obstructions. Using a proprietary, experimental, VHF short-pulse "mining radar" system, two cycles of field testing and equipment improvement were completed. Measurements were made in three bituminous coal mines, a quarry, and a salt mine. Comparisons were made with ground-penetrating radar equipment developed by others for salt dome exploration and for military tunnel detection. The proprietary mining radar equipment and techniques used were found to be the most effective known for coal exploration, but further improvements are needed; one major problem in all systems is interfering clutter signals arising in the equipment and from mine room reverberations through leakage coupling of the antennas to the air. Nevertheless, several practical goals have been achieved: excellent radar reflections were received and identified through up to 30 feet of coal; reflections from a wet, abandoned drill hole were identified by their polarization property and detected at distances up to 272 feet, and mine-wall reflections were detected at distances up to 735 feet (both through salt); propagation through and reflections from large vertical clay veins in coal were demonstrated; experimental results agree reasonably well with theory. The results and experience gained during the project affirm the feasibility of the method. They also provide a firm basis for the development of a practical radar technology for exploration in advance of mining. No Subject Inventions, as defined in the contract, were made in the course of this work.

Jan 1, 1971

By B. Stas, L. Siska, L. Dlouhy, A. Skrabis

The basic research program of the Scientific Coal Research Institute at Ostrava - Radvanice into the problem of geophysics has been influenced by the specific nature of present urgent geo- physical problems in mines and directed to attain higher grade of effectiveness, safety, and overall economy in mining activity. The research has been divided into two basic trends: Seismoaccoustic research deals with questions pertaining to safety in mining especially when work is in coal seams under "heavy roofs", i-e., thick beds of sandstone prone to rock bumps and characterized by caving. Methods have been developed with the definite aim to determine the time and space prognosis of critical states of tension in the rock mass when stability is disturbed as a result of mining activity. Seismic research is directed towards the determination of detailed structural and tectonic elements of the internal geological formation of the Carboniferous rocks, the establishment of continuity or tectonic faulting of coal seams, and the evaluation of magnitude, shape, and time changes in the rock mass surrounding the mine workings. The measurements have been applied either from the surface or in the underground workings according to the specific nature of individual problems. Satisfactory results have been obtained in some branches of this research, other branches being still in the stage of development. Remarkable results have been achieved in the development of seismoaccoustic methods designed to establish the time prognosis of dangerous dynamic phenomena accompanying the process of strata deterioration above the worked longwall face. One of the most

Jan 1, 1971

By R. D. Brown

The Federal Government's White Paper on Tax Reform received further major criticism in the reports of the Committees of the House of Commons and the Senate, which recently completed a lengthy review including public hearings of the government's proposals. These reports both criticized the emphasis placed by the White Paper on its concept of tax equity rather than on a system which would promote economic growth. However, the Finance Committee of the House of Commons was prepared to accept, with modifications, a number of the White Paper's key reform proposals. The Senate Finance Committee was more critical of the basic thrust of the tax reform program and recommended that a modification of the existing tax system would be more appropriate to Canada's needs. Both Committees re-commended a more favourable treatment of mining income than that originally proposed in the White Paper, and to some extent both Committees suggested proposals that were even more favourable to the industry than those set out in Finance Minister Benson's amended proposals made in August of this year. This article out-lines the principal recommendations and comments in the reports of both the House of Commons Committee and the Senate Finance Committee.

Jan 1, 1971

By S. C. Schaefer

Thermodynamic properties of indium oxide (In203) have been studied with a high-temperature galvanic cell employing stabilized zirconia electrolytes. In the temperature range 790° to 1,230° K the free-energy change for the cell reaction 21n(1) + 3Cu20(c) = In203(c) + 6Cu(c) together with the standard free energy of formation of cuprous oxide gives the standard free energy of formation of indium oxide from the elements as ?Gf° = -218.78 + 75.34 X 10-3T ±0.7 kcal/mole. A third-law analysis yields the standard enthalpy of formation: ?Hf°298.15 = -221.5 kcal/mole.

Jan 1, 1971