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By J. S. Wakeman

The techniques of testing the physical properties of green pellets produced in a batch balling test are described. It has been found that these physical properties, i.e. drop resistance, wet compressive strength, and plastic deformation under load, are generally related to the moisture content of the wet balls. A "criterion" method of analyzing data from a series of batch tests is discussed. This method facilitates the comparison of results of various test series. A time-sharing computer program, which correlates the test data from a batch series, generates the "criterion" values for subsequent comparison and analysis, and produces X, Y plots of the various moisture-strength relationships, is presented. Examples of computer output and use of the "criterion" evaluation method are given.

Jan 1, 1973

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

SUMMARY The objective of this program was to develop a system to extinguish coal mine fires by remote sealing of the underground passageways. The system developed had to be versatile enough to function under a wide range of operating conditions, including large variations in passageway geometry, depth of mine, water conditions, both in the mine and at the surface, and rubble in the mine passage. The system developed had to include instrumentation for the remote probing of the passageway prior to sealing, a system for sealing the mine passages, and instrumentation for remote monitoring of the quality of the seal during and after construction. These objectives were successfully achieved during this program. The remote mine sealing capability of the system was satisfactc rely demonstrated in a field test conducted at the Eastern Associated Coal Corporation Federal No. 1 Mine in Grant Town, West Virginia. The remote sealing consists of: (1) A sonar initial probing system which can operate satisfactorily even in the presence of dense smoke. The system is capable of determining both the local passageway geometry, identifying the presence of cribs and other obstructions, and the position of the borehole in the mine passage. (2) A mine sealing material system which utilizes fly ash for making the complete seal or as a bulk filler in conjunction with a urethane, froth foam, seal topping system. The choice of using fly ash alone or fly ash with foam topping depends on a number of factors, such as quality of seal desired, time available per seal, depth of borehole, passageway geometry, and water holding require¬ment. The fly ash-foam seal is a better seal, capable of sealing against a higher water head than fly ash alone. The fly ash sealing

Jan 1, 1973

By Ann G. Kim

Samples of gas were obtained directly from the coalbed during drilling of horizontal and vertical boreholes in six different formations. The samples were analyzed by gas chromatography for C1 to C5 hydrocarbons and for 02, H2, H2, He, and C02. Methane in the gas varied from 63 to 99 percent; carbon dioxide from 0.1 to 15 percent. The CH4 /CO2 ratio varied and showed no apparent correlation with age, rank, or bed. The majority of samples contained ethane, propane, and butane; hydrogen and helium were found in some samples. Oxygen and nitrogen were usually present, possibly as a result of air contamination. A more extensive sampling program would be necessary to establish relationship between the amount and composition of the gas in the coalbed and other factors.

Jan 1, 1973

By K. J. Liles

The Bureau of Mines conducted laboratory semicontinuous and continuous heavy liquid tests to determine the feasibility of producing commercial-grade products from the high-clay sylvinite ores of the Permian Basin in New Mexico. Continuous test operations demonstrated that concentrates containing 59.9 percent K2O and recoveries of over 75 percent of the contained potash can be obtained. The organic heavy liquid was effectively recovered by vaporization, condensation, and absorption methods. Less than 5 parts per million of heavy liquid vapors were released to the atmosphere. This loss represents only 0.02 pound of heavy liquid per ton of ore treated.

Jan 1, 1973

By Lloyd H. Banning

With the ever-increasing demand for energy in all forms, electrical energy generated from geothermal resources could become an important energy source in the next few decades. Geothermal fluids, which contain appreciable quantities of dissolved salts and gases, are generally corrosive to materials of construction. Since data on corrosion of materials in geothermal brines is limited, the literature was surveyed through February 1972 to obtain a compilation of information on corrosion resistance of aluminum and its alloys, copper and copper-base alloys, carbon steel and cast iron, stainless steels, chromium-iron alloys, nickel-and cobalt-base alloys, and titanium in heated brines including sea water.

Jan 1, 1973

By T. F. Tomb

Past experience has shown that the penetration characteristics of the 10-mm nylon cyclone used on approved personal sampling equipment are significantly different from those determined in the laboratory using a nonpulsating flow source. The Bureau of Mines has developed and recommended a modification to presently approved equipment that will alleviate this difference. However, as a result of this modification, a new relationship for converting respirable dust concentrations measured with approved personal sampling equipment to equivalent concentrations as measured with an MRE instrument will have to be established. This Bureau of Mines report describes the underground sampling program conducted to establish a new factor for converting respirable dust concentrations measured with personal sampling equipment, modified with a recommended pulsation damping device, to an equivalent concentration as measured with an MRE gravimetric dust sampler.

Jan 1, 1973

By D. G. Kuehn

Mass spectrographic studies have been conducted on the positive ions and neutral species of glow discharges containing 1.0 pct S02 and 1.0 pct CO in helium. Measurements were conducted for gas pressures from 3.5 to 10.1 torr using both dc and 60-Hz ac excitation. The ion species that were observed included S+, SO+, SO+, 0+, O2+, C+, CO+, and CO2+ with lesser amounts of SO3+, (CO)2+, SCO+, and (SO?CO)+ or CS+2. Interpretation of the functional dependence of the various ionic and neutral species on pressure and applied power showed that CO reacted with the SO formed in the discharges to produce CO2 and sulfur. Deposition of elemental sulfur was observed in the plasma container.

Jan 1, 1973

By R. V. Ramani

In 1970, of the 603 million tons of coal produced in the United States, 339 million tons, or 56%, were produced by under- ground mines. While the ratio of underground to surface production has been decreasing in the last few years, it is anticipated that a 60:40 ratio of underground to surface-mined coal will remain for some time. Underground coal operators are continuing to invest in new mines and are interested in increasing the efficiency of all their operations. One area for improvement is in mine planning and design, particularly in the area of selection of equipment for operation. Because of the availability of a wide variety of equipment, a fair degree of selectivity can be exercised in the choice of equipment for a particular job. However, such a choice must be made on the basis of technological facts and forecasts related to the mining operation. If the mining conditions can be reasonably predicted, along with a mining plan, it should be possible to insure the selection of the right equipment for the particular application. In order to increase the efficiency of underground coal operations, it is necessary to understand not only the operating system in detail, but the inter-relationships between system components and the operating environment. With such an understanding comes the application of simulation and other operations research techniques to plan and operate mining systems. Computer simulation studies have been successfully adapted to underground coal mining, and applications by Prelaz et al. (1965), and Manula and Sanford (1969) are some that are being used by the mining companies. However, a need still exists for better understanding of certain intra-system and system-environment interactions in order that computer simulation programs may be provided with better input data for more effective application. This paper deals with one aspect of the coal-winning system in need of better definition, namely, studying the performance of continuous miners.

Jan 1, 1973

By G. Richard Dreese

Most coal mining states have passed or amended laws restricting strip ruining in the past two years. In light of this and in anticipation of further restrictions by the states and the federal government on strip mining this paper attempts to show the Impact of these new laws on the structure of the coal mining industry in Ohio and specifically on one small stripping firm in Ohio. The implications of the study are applicable to other states under similar circumstances and to other industries which are being caught up in the ecological-economic struggle.

Jan 1, 1973

By D. F. Cooper, J. G. Paterson, K. H. Pang

"Effective control of metallurgy by manual adjustment of cell levels is common flotation practice. With an on-stream XRF analyzer interfaced to a process control computer it is possible to program the computer to carry out this function automatically. This paper describes the development and implementation of closed loop control of the concentrate and tailing grades at the Clarabelle Mill of the International Nickel Company of Canada, Limited, The XRF analyzer was used as the sensor, cell level as the control and the computer as the controller.IntroductionThe International Nickel Company of Canada, Limited recently brought on-stream Clarabelle Mill having a rated capacity of 35,000 tons per day. The plant was required to increase milling capacity in the Sudbury area by 9,000 tons per day and to improve milling efficiencies by replacing the obsolete crushing and grinding equipment at the Copper Cliff Mill. This represents the fourth mill built since 1959 and incorporates the latest thinking in a continuing evolution of instrumentation and control concepts. Table 1 illustrates control progress at Inco since 1959.In 1967 Frood-Stobie Mill came on-stream incorporating a central control room, an on-stream analyzer, a data gathering computer, and a significant change in instrumentation from direct-contacted pneumatic to miniature electronic. The computer successfully controls the analyzer but has very limited process control capability. Based on this experience a process control computer system was installed at Clarabelle Mill with the objective of carrying out extensive supervisory control and a limited amount of direct digital control."

Jan 1, 1973

By T. F. Tomb

This paper describes field and laboratory investigations conducted on a dust-collection system recently designed for integral use with a continuous mining machine. The results of the field study showed that the average respirable dust concentration measured at the machine operator's position was reduced by about 60 percent (from 8.7 to 3.5 milligrams per cubic meter), and total and respirable dust concentrations in the return air were reduced by approximately 70 percent. The data indicated that approximately 20 percent of the dust generated at the face was not passed through the scrubber. The lab-oratory results showed that the overall efficiency (by particle count) was approximately 80 percent for total dust concentrations (minus 20 micrometers in size) typical of those encountered underground. Calculations based on total dust concentrations measured during the underground study indicated that the respirable mass concentrations of the effluent from the scrubber would still exceed acceptable levels even if scrubbing of all the air at the face were possible.

Jan 1, 1973

By P. Somasundaran

Previous studies on semi-soluble minerals such as calcite (1) and apatite(2) and sparingly soluble minerals such as quartz (3,4) have given evidence for significant changes in their electrokinetic properties as a function of aging time. Such changes are relevant to mineral processing operations where the crushed ore particles might not have yet reached equili¬brium with the water that it is in contact with. In order that these changes be studied under controlled experimental conditions for long periods unattended or with fairly less intermittant attention, a streaming potential apparatus with an automatic streaming system was constructed. Also, a new streaming potential cell was incorporated into the system so that the effect of temperature, a variable coming into increasing usage in mineral processing operations(5), could also be studied. Conventional streaming cells(6) cannot be safely employed to conduct studies as a function of temperature since they have many glass joints that are prone to leakage, parti¬cularly under pressure, in the course of an experiment. This paper describes the new apparatus and some typical results that have been obtained with it far temperature effects.

Jan 1, 1973

By C. B. Kenahan

A summary of Bureau of Mines research on recycling, reuse, and disposal of mineral-, metal-, and energy-based wastes is presented, accompanied by an extensive bibliography of related publications. The Bureau's waste recycling and disposal program is directed toward the following four main areas of research and development: (1) extraction of mineral, metal, and energy values from urban refuse; (2) upgrading and recycling of automotive and related ferrous and nonferrous scrap; (3) recovery, utilization, and stabilization of mine and mill processing wastes, and (4) recovery and reuse of values from industrial waste products. This publication updates Bureau of Mines Information Circular 8529, which was issued August 1971.

Jan 1, 1973

By C. S. Simons

The conversion of a successful research and development effort into a money-making business venture requires careful attention. Problems of a business nature, such as market size, product selling price, raw materials and fuel availability and cost, financing factors, local and national taxes, licensing arrangements, etc. must, of course, be considered and resolved. In addition, the technical questions involving the scale-up of pilot plant or laboratory results to the full-scale plant must be resolved in order to avoid the financial disaster that attends a major delay in the startup of a commercial facility. The very difficult and demanding task of providing the interface between the research laboratory and the profitable metals processing plant will be discussed with examples from the author's extensive experience. After I had accepted the invitation to present a paper on the above subject of the interface between R & D and production operations, I began to give some serious thought to the subject. The program chairman had told me, in conveying the invitation, that what the committee had in mind was a discussion of positive and negative, forces in that interface, based on "gray-hair" experience. I am, therefore, at least physically qualified! My first reaction was one of mild shock; after over twenty years in the direct pursuit of the conversion of research and development findings into plant operations, I had never tried to sort out my , experience into a formal system of DO'S and DON'TS for the edification of posterity. However, after a little further reflection, I realized that this carries no stigma. No one has been able to formulate such a set of rules, and it is not really very likely to be done. Particularly if they are to be practical. I shall therefore settle for a more modest goal; I will simply discuss the factors that I have come to believe are the most critical in insuring that re- search and development results are converted into successful operation.

Jan 1, 1973

By D. C. Fraser, W. J. Scott

"Airborne electromagnetic surveys were flown during 1965 in the Moose River area of Ontario. The systems used were INPUT Mark II and the Canadian Aero Otter. Anomalies indicated by both systems were located on the ground with vertical-loop EM. Two such anomalies were drilled, with no explanation being found in the bedrock geology. Subsequent seismic, resistivity and gravity surveys indicated that the sources of these anomalies lay in the overburden. Current work in the similar geological environment of the Winisk River area has shown that comparable AEM anomalies can still be misleading. The lesson to be, learned from these experiences is that additional geophysical work can help to resolve doubtful cases before drilling decisions are made."

Jan 1, 1973

By Donald M. Hausen

Microscopic evaluation of trace quantities of metalliferous phases in flotation products requires counting large numbers of particles. Particle counts of many thousands may be required for precision, but cannot be obtained practically by conventional microscopic techniques. A less tedious microscopic method for evaluating trace sulfides in mill tailings was developed for the O'okiep Mining Co. in South Africa. Hundreds of thousands of particles were evaluated by this method called "gross-counting." Gross-counting consists of counting microscopic fields rather than point-counting individual particles. Total counts are calculated by multiplying the average number of particles per field by the total number of fields examined over the entire mount. Total gross-counts range from about 20,000 particles for +200 to 100,000 or more for -400 mesh size material in lucite mounts. Sulfides and metallic particles in each field are identified and tallied along with field counts. Totals for each type of metallic particle are divided by the total gross-count to give volume percent which is corrected to weight percent by specific gravity factors.

Jan 1, 1973

By D. R. Buist

The Taharoa plant of New Zealand Steel Mining Limited extracts a 57% Fe titano-magnetite concentrate from a large mineral sand deposit 90 miles south of Auckland on the west coast of New Zealand's North Island. The plant consists of an 18-inch suction cutter dredge which feeds a 750 TPH floating separation plant. An initial gravity/ size separation is obtained using cone concentrators. Finished concentrate is produced by a combination of conventional drum magnetic separators and top fed wet Mortsell magnetic separators. Concentrate is stockpiled by cyclone, and reclaimed by a bull- dozer and tunnel system. Repulped concentrate is pumped by sub- marine pipeline to slurry tankers anchored at a single buoy one mile offshore. Current concentrate production rate is in excess of one million metric tons per year.

Jan 1, 1973

By W. H. Pelton, P. G. Hallof

Outlining small pods of high-grade, massive sulfide, copper-zinc mineralization was the object of an intensive exploration program by Long Lac Mineral Exploration Ltd., near York Harbour, Newfoundland, Canada. Efforts to define the ore zones using surface dipole-dipole induced polarization techniques were not entirely successful due to the poor size-to-depth ratio of the targets and widespread disseminated mineralization. Additional information on the size and shape of the sulfide bodies was obtained by placing a current electrode directly within a mineralized drill intersection and systematically measuring the resultant potential on the ground surface. Some simple potential field sources were interpreted from the data and their validity has been shown by an extension to the underground workings.

Jan 1, 1973

By John S. Berber

Acids, neutral oils, and pitch were produced by distillation of low-temperature lignite tar and processed to upgrade them into more valuable products: The acids were separated from the distillate and catalytically dealkylated to produce phenol, cresol, and xylenol. Aromatic and naphthene fractions of the neutral oil were converted into phthalic and maleic anhydrides by catalytic hydrodealkylation and vapor- phase oxidation. Paraffins and n-olefins from the neutral oil were processed into alkybenzene sulfonate, a biodegradable substance. Aromatic materials from the neutral oil were also extracted with organic compounds and the extract hydrogenated under pressure to produce jet fuel. The pitch was processed by various means to change its characteristics and make it suitable for similar applications as high- temperature tar pitch, including preparation of carbon black and metallurgical electrodes. In most cases, products obtained from the low-temperature tar were examined for physical and chemical characteristics and for potential commercial utility. Information obtained from this research would be helpful if a new coal- chemical industry based on tar utilization were established.

Jan 1, 1973

By M. Mentser

The exchange of oxygen between carbon dioxide and carbon monoxide that occurs reversibly on carbon surfaces was studied at temperatures of 750° to 850°C and a pressure of 1 atmosphere. Carbon-14 was used to detect and measure the exchange reaction. The extent of oxygen exchange was a linear function of com- position of the gas mixture, and this relationship was used to evaluate the forward and backward rate constants of the reaction. Equilibrium constants, directly determined for oxygen exchange in this study, agreed well with values in the literature that were derived only by indirect procedures. This result establishes the validity of oxygen exchange in the mechanism of carbon gasification by CO2. Rates of carbon gasification were less than an order of magnitude slower than rates of oxygen exchange. Activation energies for these two processes were 58 and 53 kcal/mole, respectively. The closeness in the activation energies argues against any change in the rate-controlling step over a wide temperature span at atmospheric pressure. The role of CO as a retardant on the CO2-C reaction, and the nature of the carbon-oxygen complex are also discussed in view of the data obtained.

Jan 1, 1973