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By Colquhoun L

Flooding velocities were measured in a laboratory column (96 mm 4) provided with both bottom and side air entry Packings used were 6 mm glass rings and spheres and -16 +8 mm coke. Results showed that when air was introduced through side nozzles flooding velocities were much higher than those obtained when air was introduced at the bottom of the column. Significance of the results and application to blast furnace flooding is discussed from the viewpoint of assymmetric gas flow.

Jan 1, 1975

By Homer E. Harris, William C. DeSieghardt, William A. Burgess

Under sponsorship of NIOSH, Eastern Associated Coal Corp., with the Harvard School of Public Health acting as a subcontractor, has determined for the first time the effective protection provided to working underground coal miners wearing approved half-mask dust respirators. This was done by conducting 187 man-shifts of in-mine testing in four different coal mines; included in this testing were 37 different test subjects representing 11 different job classifications and 5 different models of respirators. Presently available respirators on average provided significant protection levels to working miners even though on an intermittent use basis. However, "average" protection values were well below those achieved under laboratory conditions. Protection levels varied from man to man in a given work crew and from day to day for a given man. In addition, some of the factors affecting use and effectiveness of presently used respirators are discussed, as are areas in which improvements are needed, and the need to consider these improvements in context of a systems approach.

Jan 1, 1975

By James E. Lawver, Jose M. Pastrana

Some of toe magnetic properties of minnesotaite (general formula: Fe3(OH)2Si4O10) were examined. Toe paramagnetic susceptibility values at various temperatures were determined from toe slope of toe magnetizing curve. These values were then compared with toe theoretical values estimated using toe Bohr magneton numbers for toe paramagnetic ions contained in toe missesotaite.

Jan 1, 1975

By F. N. Kissell, C. M. McCulloch, Maurice Deul, J. R. Levine

The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to determine if degasification of the coalbed will be necessary before mining, and to determine the gas resources in the coalbed. The equipment necessary to conduct the test costs less than $50. The gas content of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. Upon removal from the borehole, the core sample is placed in an airtight container and desorbed for several weeks until the desorption rate is below 0.05 cm3/g for 5 consecutive days. The gas lost from the core while it was being cored and the residual gas are estimated by a new graphical method. The amount of gas remaining depends upon whether the coal is friable or blocky. Friability appears to relate to the depth of the sample below the surface, fixed carbon percentage, Hardgrove grindability index, and proximity to tectonic disturbance. Friable coals emit nearly 96 pct of the total gas during desorption whereas a blocky coal emits only 60 pct of its total gas. Coalbeds that are ill defined as to their blocky or friable nature must be tested in the laboratory for unambiguous analysis.

Jan 1, 1975

By R. H. Sprute

Extensive Bureau of Mines laboratory testing has shown that electrokinetic densification can be an effective method for dewatering and consolidating unclassified metal mine mill tailings. The report describes results of a limited field test of this technique. Eighteen-cubic-yard concrete model stopes, 18 feet long by 6 feet deep by 56 inches wide, were filled with unclassified tailings slurry from a metal mine in the Coeur d'Alene, Idaho, district. Five different tests were performed. They showed that a strong, dense, dewatered fill can be obtained in a reasonably short time using electrokinetics, with typical power consumption of 25 to 30 kW-hr/yd3 of densified fill. At present power costs in the Coeur d 'Alene district, this would amount to 10 to 12 cents/yd3.

Jan 1, 1975

By Galen Bauer

"Up until the mid 1960's, the only available methods for making continuous weight measurements were through the use of mechanical and electro-mechanical weigh scales. It was during this time period that a new concept in weighing was introduced. It was known and is still known as the nuclear belt weigh scale.During the early days of its appearance in the market place, many things were learned about its advantages and disadvantages for weighing various materials. As with many new devices, it had to go through a ""wringing out stage"" before it became accepted by the weighing industry. Even today, even though it is a proven device, there are skeptics who believe the nuclear belt weigh scale will not survive. Let me assure you, it is here to stay.. 'PRINCIPLE OF MEASUREMENTThe nuclear belt weigh scale consists of a ""C"" Frame assembly which houses the radioactive source (Cesiwn 137) and the radiation detector (Ionization chamber). The ""C"" Frame assembly is put in place around the conveyor belt as shown in Figure 1. The radiation source emits a fan shaped beam of radiation which covers the full width of the material being conveyed on the belt. Radiation which has passed through the material on the belt is detected by the ionization chamber which is located in the lower arm of the ""C"" Frame assembly. The ionization chamber changes the radiation energy into an electrical signal which is related to pounds per foot belt loading. This signal is transmitted to a highly stable amplifier which combines the pounds per foot signal with a belt travel signal from a digital tachometer which allowed the scale user to be able to monitor total mass being conveyed. Many so-called conventional type scales use belt speed rather than travel to obtain mass per unit time, and then integrate the signal to obtain their weight signal. This unnecessary step tends to erode the overall accuracy of the weighing system."

Jan 1, 1975

By Raymond F. Moran

The history and development of the FMC Coke process has been reported in numerous presentations over the past 10 years (1, 2, 3, 4, 5, 6) but a short review is desirable, especially regarding the aspects that are influenced by the coal to be used. F'MC has been developing this process in pilot facilities since 1956 and in a modest sized plant in Kemmerer, Wyoming since 1960 (Figure I). This plant produces strong uniformly sized coke briquettes from a completely non-coking coal, namely Elkol, a sub-bituminous coal of the Adaville seam. Since operating commercially, over 300,000 tons have been produced, 90% of which has been used in electric phosphorus furnaces and some 10% of which went for trials in iron blast furnaces. We believe that this commercial use of non-coking coals is a unique experience in the history of coke manufacture.

Jan 1, 1975

By C. J. Cattarello

"The Langmuir Mine is located seventeen miles south-east of South Porcupine in Langmuir Township.The property was developed as a Joint Venture between Noranda Mines Limited and the International Nickel Company of Canada with Noranda responsible for the operation of the property.The Mine came into production in June 1973 at a rate of 700 tons per day of nickel ore.MINING The mining method selected for the Langmuir Project was a sub-level retreat method. This consisted of driving sub-levels longitudinally in the ore body at 35 foot, intervals with the sub-levels being connected by a ramp from each main level for the use of trackless mining equipment.GENERAL GEOLOGY OF THE LANGMUIR MINE The deposit is situated about 1,000 feet west of the shore of Carmen Bay at the south of Nighthawk Lake in Langmuir Township. The area is underlain by andesite and rhyolite flows with iron formations which are intruded by gabbro, diorite, peridotite and late precambrian diabase dikes."

Jan 1, 1975

By John P. Wagner

The details of a three-phase study (total time period of 12 months) entitled ?Fire Alert Systems for Metal and Non-Metal Mines,? are presented. Phase 1 consists of a state of the art survey on fire detection devices and gas sensing techniques. Phases 2 and 3 include laboratory screening and systems concepts testing on various detectors classified as products of combustion, optical view-field and contact (or thermal) types under incipient and flaming combustion conditions. Recommendations for a mine fire detection system to protect shaft, sealed off or mined out (from spontaneous combustion of sulfide containing ores and cellulosic materials), and fuel storage areas are also included. me principal problem area noted during Phase 1 study is the high expected occurrence of false alarming of products of combustion detectors (POC") subjected to normal mining operations---diesel vehicles and equipment and shot firing or blasting operations. Simultaneous gas sensing of either the ratio of CO/NOx or CO2/NOx with detection of one or more fire signatures (smoke, radiant energy, or heat sensing) is the recommended approach to discriminate against these operations.

Jan 1, 1975

Coal mining safety and health legislation is more than typical of safety legislation which has been born of adversity. Indeed, in the main it has been the child of disaster. Requirements which now appear obvious were indeed only occasioned by either social injustice or more commonly by great disasters. Even then changes were often made only after months or years of deliberation by committees. Early mining legislation in New South Wales benefited from the experience in Great Britain. The pioneers of our industry were miners from there and brought with them the basic British legislation, so we started with knowledge gained the hard way. A review of accidents statistics provides a measure of the effectiveness of mine safety legislation, but unfortunately rules cannot control human nature. Miners, managers and inspectors must work as a team to make mines safe and new legislation in New South Wales is planned to this end.

Jan 1, 1975

By P. Somasundaran

An experimental and theoretical treatment of the depressing effect of inorganic electrolytes on the amine flotation of quartz is presented. Experimental data obtained for the amine flotation of quartz as a function of pH with potassium nitrate as depressant was used to test the models for the effectiveness of inorganic ions as depressants. The validity of commonly used assumptions are examined. The surface tension data obtained for dodecylammonium acetate solutions as a function of KNO3, concentration indicated that the collector adsorption on bubble cannot be neglected in the treatments, since this adsorption changes significantly with the addition of the inorganic electrolyte. It also indicated the possibility of significant changes in the specific adsorption potential of the collector occurring with the addition of inorganic electrolytes.

Jan 1, 1975

By Mills JC, Belcher CB

X-ray fluorescence spectrometry is used videly for routine quality control of the mining, )lending and agglomeration of iron ores. Most )f the procedures used, cannot tolerate significant changes in matrix composition or be Lpplied to a wide range of elements. Accord- ngly, a graphite briquette technique which is Lpplicable to some fifty elements in widely Tarying iron ore matrices is described. The ignificant advantages are suitability of the ame preparation for both optical emission and -ray spectrometry, a complete elemental overage for the range 5bcg/g to 100%, and the recision and accuracy of the methods are om.parable with the standard chemical.methods hich have been superseded in the authors' boratories. The proposed methods become ore attractive and economical as more prehensive information is sought.

Jan 1, 1975

By K. Thirumalai

The feasibility of breaking hard rock by thermal weakening and subsequent mechanical impacting was tested, Field tests at a basalt quarry in Dresser, Wis., demonstrated that large hard-rock blocks (5 by 5 by 5 ft) could be effectively reduced in size by this method. A series of secondary breakage tests, using air-propane heating, resulted in an average heating cost of $0.36 per ton. This combination energy approach provides an alternate means of size reduction of large hard-rock boulders for quarry and for underground are chute and grizzly operations where mechanical methods, used alone, are ineffective.

Jan 1, 1975

This report summarizes the cost of U.S, mining and milling industry compliance with the Environmental Protection Agency (EPA) interim water quality guidelines for waste discharges. Applicable excerpts from Public Law 92-500 are stated and interpreted in conjunction with the guidelines being used for implementation of the law. Over 200 U.S. Army Corps of Engineers applications for discharge permits were used to develop the quality and quantity data base needed to estimate the cost to comply with EPA guidelines, Cost of three basic treatment methods were considered: Aeration, addition of lime, and sedimentation. From the process design, cost-capacity graphs were developed to consider maximum flow rate, maxi lime addition, and average flow rates. The graphical method used in this evaluation should provide a reasonable guide to the effect of waste treatment and, therefore, Public Law 92-500 and corresponding EPA guidelines on the mineral processing industry. The cost of complying with the EPA guidelines will have the effect of prompting the mining industry to minimize the production of waste water and of undertaking some additional treatment, Two case studies are presented to illustrate efforts that might be fruitful for minimizing waste water production and for treatment of combinations of acid mine drainage, mill wastes, and metallurgical process wastes when treatment is deemed necessary.

Jan 1, 1975

By Denholm WT

The Dittmer process for the debismuthising of lead by electrolysis beneath molten caustic soda has been scaled up to 100 kg lots for batchwise operation and to 20 kg per hour for a continuous flow of lead. Bismuth was decreas- ed from 0.03 to less than 0.005 wt. per cent for an electricity consumption of 220 kWh per ton of lead. Lower bismuth levels may be readily achieved if required.

Jan 1, 1975

By James A. Bloom

To operate the Morris Fork Preparation Plant with a closed water circuit has been an elusive goal for Union Carbide. The benefits of a closed circuit have never been questioned. The removal of fine solids from washery water makes possible the recirculation and reuse of the water. Heavy media drag tanks and other separating machines perform better and more consistently with washery essentially free of fine solids. Finally, the production of a clarified effluent makes unnecessary the sludge ponds usually associated with a coal preparation plant. Why then do I say elusive? Because, since plant design was completed in 1970 we have been in hot pursuit of an ever-growing fine solids problem. In four years the minus 28 mesh material in the plant feed has nearly doubled. The replacement of conventional sections with continuous mining machines has led to a lowering in size and quality of product from the mine. In addition, increasing emphasis underground on roadway clean-up has contributed to the fines problem.

Jan 1, 1975

The published safety policy of Mount Isa Mines Limited, together with details of the organisation and control techniques adopted by management to pursue an active safety programme within the company, is presented. The importance of communication by management through the organisational hierarchy and procedures instituted to ensure rapid and concise feedback on safety concerns are detailed. The paper also describes the role of the occupational health department and safety committees in assisting management to monitor the safety effort of supervisors and employees. Current safety performance levels are tabled together with details of some aspects of the programme on which safety effort will be concentrated in the future.

Jan 1, 1975

By Joe Dannenberg

One must be cautious in talking about blasting safety, because the very act of making a blast involves the creation of an infernal machine. You are setting up for the instant release of tremendous energy. Inherently this is a hazardous act. It has always been hazardous. It will stay hazardous.

Jan 1, 1975

By H. Schultz

Urban refuse that was mechanically separated at the U S Bureau of Mines pilot plant in College Park, Md., was successfully evaluated for its fuel values using standard coal analysis methods. Analyses performed on refuse samples taken from five sample points included moisture, ash, sulfur, chlorine, and heating value. It was recommended that characterization of the combustible portion of urban refuse by standard coal analysis procedures should be widely adopted.

Jan 1, 1975

By R. R. Givler

Since the 1860's the good ole days, oil has been nozzle fed to burners under pressure atomizing the oil into droplets -- 1960's has produced vaporized oil that burns oil with the flame color and consistancy of gas -- If you can tell the difference by looking at the flame, gas or oil I?ll buy the lunch. First, we must ask, "Why all the excitement about Blue Flame?" This question is best answered by you after you have studied the principle of operation and see the result. I will attempt to explain both of these so that you can draw your own conclusions.

Jan 1, 1975