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By Hopkins G. M F

Intensive exploration of the Archaean ultra mafic sequence bordering the Kambalda dome has resulted in the discovery of at least ten dis- tinct areas of nickel sulphide mineralisation subsequent to the initial drill intersection in January, 1966. Sulphide ore reserves to June 30, 1972 were 19.36 million tonnes at 3.3% nickel after mining of 3.0 million tonnes at 3:7%,nickel since production commenced in March, 1967. About 75% of contained nickel metal reserves occur in sulphide concentrations located at the base of the-ultramafic sequence, in contact with underlying meta-tholeiitic basalt. The remaining reserve occurs in concentrations of sulphides within the ultramafic sequence, usually within 100 metres of the underlying contact and typically in proximity to contact mineralisation. These hanging wall orebodies are smaller, contain significantly lower con- centrations of sulphide, and generally exhibit higher Ni:S ratios than underlying contact ore- bodies. The majority of contact sulphides concentr- ations form narrow, elongate, north north-west trending bodies, closely coincident with fault bounded depressions in the contact. Detailed study of the Lunnon Shoot ore environment in- dicates that it was a locus of crustal failure during, and subsequent to, emplacement of ultra- mafic rocks. Resultant structures parallel and

Jan 1, 1973

By R. J. McLeod

"CONTROL STRATEGYThe Lake Dufault Division of Falconbridge Copper Limited has been concentrating a complex copper zinc ore since late 1964. An ARL X-ray on stream analyzer was installed in 1966 for process control. A Digital Equip-ment Corporation PDP8 was added in 1968 for more complete control. To improve the system the computer was exchanged for a Moded PDP-81 in 1971.The new computer is time sharing with 8K core memory and 32K disc storage. A new interface was installed to accommodate 14 X-ray streams and additional analog signals for process control. The system gave us additional capacity and flexibility to make changes in operating programs and control strategy while on line. As the computer is used for process control a modified focal language was chosen as the operating language for ease of operation. This language is more suitable for process control than for statistical work.The main components of the control system are(a) Computer(b) Interface(c) Production Control X-ray Quantometer(d) Teletype terminals(e)Reagent feeders(f) Sample SystemThe operation of the system consists in the computer selecting the various streams to be analyzed by a PCXQ Quantometer. When the flowing sample is presented to the X-ray the intensities of the various elements are read by the computer from analog to digital converter, the assays are then computed. From the tonnage and assays the computer is programmed to determine the amount of reagent added to various parts of the circuit. The computer drives the feeders via the interface for the required amount of reagent. After following a certain sequence the computer prints out the performance and control data on an ASR35 Teletype. The data is printed out approximately every seven minutes. Any des¬ired changes in the program or strategy can be made during operation via an ASR33 Teletype connected to the computer."

Jan 1, 1973

The purpose of this report is to describe the work accomplished by Mine Safety Appliances Company under Contract No. H0110845. This contract required the design, installation and testing of a permissible mine surveillance and communication system for the USBM Bruceton experimental mine facility. While much of the design and operational detail of this system can be drawn from the instruction manuals delivered with the equipment, some of it will be repeated here in Volume I for the sake of clarity, but the principal objective will be to report on overall system and subsystem performance and to suggest design alternatives for future consideration. Details of the overall system design will be found in Volume II of this report.

Jan 1, 1973

By Hill J. R M, McDonald M. M

A prediction technique for support perfor- mance of hydraulic backfill in narrow stopes is applied to two stopes separated vertically by a sill pillar. Predicted stope wall closures and fill pressures compare favorably with field measurements taken over a period of several years at two mines in the Coeur d'Alene dis- trict. Stope wall closure and peak pillar stress can be substantially reduced by improved fill quality within a practicable range of fill and rock properties.

Jan 1, 1973

The development of a noise attenuated compressed air driven fan is described. The fan, which employs the jet reaction principle, possesses blade extension pieces which penetrate into an acoustically treated annular chamber. The dominant noise source, namely the air jets, is thereby partially suppressed. In addition, the increased moment arm of the jets leads to an improved propulsion effect which contributes to the improved aerodynamic performance of the unit.A typical measure of the improvement of this type of auxiliary mine ventilation unit is a 4 per cent increase in efficiency and a 10 dB (A) drop in sound level for a fan duty of 0·5 kPa and 1600 litre/s. This degree ofattenuation corresponds to at least halving the loudness level, a subjective noise measure.

Jan 1, 1973

By David B. Brooks, Roger L. Williams

Control of the environment is as old as mining. Engineers have always had to consider how best to deal with the surface, and the character of the surface environment always affects mining method in some way. However, if the relationship of the mine to the environment is old, today's approach is new. For one thing, land, air and water formerly could be viewed simply as obstacles to be overcome or resources to be utilized to win ore at the lowest possible cost. Now we have come to realize that these nonmineral components of the environment also are highly valuable. For another thing, environ- mental protection has become a public policy issue. Again, a special public interest in land and land use is old. From the firs(, the crown claimed extra rights in valuable minerals, and to this day a multitude of laws and regulations control-and tax-land use in every country. What is new is the detailed public attention bring given to waste management practices, whether these wastes be in the form of solids, liquids or gases, and regardless of where in the environment they appear. (It is convenient to lump all mining environmental problems, including hank fires and subsidence, together under the term "waste management," for in effect that is what they are.) As a result of these changes, the mining engineer must consider that lie is dealing with two productive resources the minerals and the remainder of the environment-and he must expect that lie will be judged not only on his efficiency in recovering the one but also on his effectiveness in protecting the other. Further, in seeking to protect the environment, the modern mining-environmental engineer has a dual role. First, there is the obvious task of finding better ways for industry to cope with waste-management problems in actual operations. Second, there is the less obvious but equally important task of helping formulate appropriate public policy objectives for the environment. Throughout; the section it is assumed that mining is an acceptable land use for the tracts under consideration. The question of whether mining will be permitted at all on these tracts is a further public-policy issue, ultimately to be resolved politically and thus, since it is beyond the scope of engineering, is not a subject that can be usefully discussed in a mining handbook. Finally, none of the statements in the section are predicated on the assumption that required waste-management measures will be privately profitable in the conventional sense. Indeed, the reverse is more likely to be the case-at least if accounts are kept so as to include all appreciable costs and a normal rate of return on investment in waste-disposal and reclamation equipment.',',' However, it is clear that improved waste management will be required of mining firms and that, to a considerable although undetermined degree, this expenditure is in the best long-run interest of both public and industry. The several studies that have attempted to quantify the impact of mining on the environment are admittedly rough but still provide enough information to indicate that there is a big job to be done. For example, something approaching 7,000 mi of stream in Appalachia alone are continuously or significantly affected

Jan 1, 1973

By Basil Dimitriades

The association of automotive fuel composition with exhaust reactivity was studied in an experimental program that involved testing with different automotive engines and with gasolines of varied composition. Results showed clearly the exhaust reactivity to increase with increasing levels of polyalkylbenzenes in the fuel. No other systematic patterns of high significance were detected in the association of exhaust reactivity with several broadly defined groups of fuel components. For the purposes of this study, had it been possible, fuel composition should have been defined and expressed in terms of component groups such that the potential for exhaust reactivity would be the same within each group and different from group to group. Classification of fuel components in terms of the paraffins-olefins-aromatics groups does not meet the latter requirements. For appropriate classification of fuel components more information is needed on the combustion .of hydrocarbons in the multicylinder internal combustion engine. Statistical analysis of the mass emissions data showed significant car and fuel effects on hydrocarbon, carbon monoxide, nitric oxide, total aldehydes, and formaldehyde emission levels and on total photochemical reactivity. Car-fuel interactions were not significant at the 90-pct level. Correlations were found between mass emission parameters and fuel composition.

Jan 1, 1973

By Douglas W. Fuerstenau, Kalanadh V. S. Sastry

Based on an analysis of green pellet size distributions and kinetic data on ball growth with taconite concentrates, a ballability index has been developed to quantify ball growth behavior as a function of moisture and bentonite additions. The applicability of the ballability index to such other particulate materials as pulverized limestone and ground magnesite is shown.

Jan 1, 1973

The scope, pace and depth of mining is creating a need for improved ground control strategies to meet mine safety standards. Ground control and associated conservation problems relating to subsidence and the disposal of mining and metallurgical wastes can be resolved by mine filling with selected reject materials. The lack of suitable criteria to evaluate the applicability of such materials and especially cemented forms of fill is considered. Sulphide wastes, which are prone to oxidize, and cement are inexpensive mine fills, but their incorrect use can give rise to problems which are briefly described. Research work concerned with the utilization of sulphide wastes such as mill tailings, to produce fill with self-cementing properties has shown that the development of cohesion and strength is attributable to natural oxidation processes controlled by the physical and chemical composition of the fill mass. The cementing is caused by a number of oxidation products, and is most effective when the mineral pyrrhotite is present. The concepts of fill design are outlined and various criteria for assessing durability and deformational properties are proposed. Specimens prepared in the laboratory are capable of attaining unconfined compressive strengths up to 28 MN/m2.

Jan 1, 1973

By B. J. Scheiner

The Bureau of Mines investigated an electrolytic technique for oxidizing ore slurried with brine to determine its effectiveness in extracting mercury from ores. Optimization experiments conducted on a 2.5-pound-mercury-per-ton ore resulted in 95 percent mercury extraction with operating conditions of 30° C, a current density of 0.5 ampere per square inch, and a treatment time of 3.5 hours. Corresponding power consumption amounted to 38 kilowatt-hours per ton of ore treated. Amenability experiments conducted on 62 different mercury ores resulted in 90 to 99 percent mercury dissolution from ores containing 0.6 to 20 pounds of mercury per ton of ore, Treatment time ranged from 1 to 7 hours in 4-to 20-percent sodium chloride solutions, and power consumption was in the range of 10 to 50 kilowatt-hours per ton of ore. Pilot mill experiments in a 100-to 200-pound-per-hour extraction plant have been in progress to quantify power and reagent requirements. These data will be reported in a subsequent publication.

Jan 1, 1973

KIeeman (1968) described practice in the Mount Hebbard dump concentrator, Broken Hill, N.S.W. The purpose of this note is to give data on flotation pulp chemistry in the plant for comparison with results of Woodcock and Jones (1970a, 1970b).Ten chemical parameters were measured at ten points in the circuit using the techniques of Woodcock and Jones (1970a, 1970b). Fig. 1 shows a condensed time plot of some continuous measurements in conditioner overflow and rougher feed. Fig. 2 shows average values of selected parameters at the start and end of each of the three rougher flotation stages.DISCUSSIONpH and redox potentiaIsFig. 1 shows that pH and Eh were relatively constant at the start of sulphide lead flotation. There was a fairly steady increase in pH throughout the circuit (Fig. 2), but flotation was always conducted in a slightly acid pulp in spite of the large amount of alkaline reagents added. Eh values became more positive as the pulp progressed through the circuit (Fig. 2) in accord with results elsewhere.

Jan 1, 1973

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

9. Remote Sealing System Sensitivity 9. 1 Introduction In the previous sections a description of the overall system has been presented along with detailed descriptions of the equipment and techniques employed with the preliminary probing system, the seal em¬placement system and the seal checking system. In addition, the use of these subsystems in a specific mine application has been described in considerable detail. A broad range of parameters of interest was specified in the contract, as summarized in Section 1. 3. Most of these are a function of the general location; i. e. , the location of the mine, and the specific location; i. e. , the location of the boreholes. These parameters of interest include passage size, shape, depth, slope and water con¬ditions. The length, diameter and location of the boreholes within the mine passage and on the surface are critical parameters as well. A few additional parameters may affect one or more of the remote sealing subsystems. These include temperature, topography, rock and soil conditions, and underground water. While variation in these parameters will not render the system inoperative, consideration of them in the planning stages will simplify and expedite the field operation. In the following sections the effect of the various parameters on the remote sealing operation will be discussed. For clarity, the several tasks, borehole drilling and casing, preliminary probing, fly ash delivery, foam topping and seal checking, will each be considered separately.

Jan 1, 1973

By Bunting S. Crocker

Bunting S. Crocker (Executive Vice President, Kilborn Engineering Ltd., Toronto, Ont., Canada)-This is an interesting report on laboratory-scale testing with pebble charges in 12-in.-diam mills, and the author correctly concludes that useful laboratory testing can be done. In the opening paragraphs he states, "laboratory pebble-milling tests have been considered too difficult to perform and not relevant enough to the actual grinding situation"!! This is definitely not so! The writer published detailed tests done in a 12-in.-diam mill comparing pebble and steel balls in 1952 6 and again in 1954 7. We note that our review paper in 1963 was the only one mentioned in the References. The author states that "a smooth lining is more frequently used in commercial-scale pebble grinding." The writer has designed some 22 plants treating 134,000 tpd in North America and Australia. He has also visited pebble installations in Norway, Sweden, Finland, and South Africa. All these plants correctly use heavier lifters than would be considered standard for ball mills of a similar size. Smooth liners are not recommended in wet ore treating plants. In the 1952 paper6 it was clearly demonstrated in the test work that the individual ore pebbles had to be the same weight-not the same diameter or size-as the steel balls if comparable grinding results were to be obtained. In the tests performed in this study most of the pebbles "passed 50-mm round hole screen openings and remained on a 40-mm round hole sieve. Correspondingly most of the ball mill experiments were performed with 50 or 40-mm steel balls". Thus, the balls and pebbles were essentially the same size or diameter. This means we are comparing apples and oranges. When the feed being ground is fine enough the pebbles will be superior. When the feed is coarse the steel balls will be the better. This is similar to grinding tests in which two sizes of steel balls are compared. In the middle of the article, "Crocker5 has reported that equal weights of pebbles and steel balls achieve the same grinding capacities under similar conditions …", then he proceeds to question this postulate. In the eight reports that I have published, I have never made this statement. What I have said is "for comparable grinding, the individual pebbles in the mill charge should be the same weight as the individual steel balls." This is not the first time that I have been misquoted on this point! It is most unfortunate that this test work has been done with a ball and pebble of the same diameter and not the same weight. It is impossible to properly evaluate the results. I also regret the fact that the screen analyses of the tests were not shown. Many of us who have been 40 years or less in the grinding game can easily read screen analyses at a glance. We can tell whether the top meshes are being ground by the ball charge, etc., etc. The graphs are fine for the summary or to illustrate conclusions but are often misleading in the report itself. However, we do agree that useful pebble grinding tests can be done in a 12-in. mill.

Jan 1, 1973

The selected list of sources of information on geology and mining in this section is provided to facilitate locating the major governmental and private entities in position to furnish such information, including societies and institutes; colleges, universities and technical schools; and magazines, yearbooks and mine directories, plus a number of general texts. In the case of publications, it should be noted that, in addition to those listed, most of the governmental and private organizations publish a wide variety of reports, bulletins, monographs, surveys and the like, including, in the case of governmental agencies, production statistics. The names of the mining schools and colleges in the following, with some exceptions, were taken from the International Handbook of Universities and & her Institutions of Higher Learning, and the Commonwealth Universities Yearbook, with the kind permission of the International Association of Universities, Paris, and the Association of Commonwealth Universities, London, owners of the copyrights. Abbreviations in the listings include the following: A. P., B. P, and C. P., Apartado Postal, Boite Postal and Caixa Postal (post office boxes); Br., Branch; and F., Faculty.

Jan 1, 1973

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

3. Preliminary Evaluation of Mine Sealing Techniques As the first stage in the development of a technique for the remote sealing of mines, a state-of-the-art survey of various mine sealing techniques was conducted. This was expanded to include a review of different materials offering some potential for use as a mine sealant. Techniques for the remote placement of materials for other applications were evaluated, and system concepts for dis¬tributing remotely placed materials were developed. This preliminary review led to the development of a functional description of a general mine sealing technique to meet the specified conditions. Various potential system configurations were synthesized. These were subjected to a preliminary evaluation based on estimated confidence in system performance, development risk, cost, and sealing time. Based on this preliminary evaluation, promising mine¬sealing techniques were selected for further development. This section presents a review of the following: (a) Techniques for constructing permanent seals from within a mine. (b) State of the art in remote sealing for mine fire control. (c) Techniques for remote placement of materials for other applications. (d) Systems for distributing remotely placed material. (e) Materials for mine sealing. (f) Synthesis of remote mine sealing concepts.

Jan 1, 1973

By Michael W. Redifer

A Fortran IV computer program was developed to calculate the composition at equilibrium of products from a set of high-temperature gas combustion reactions. The program was used to develop high-temperature equilibrium concentration profiles for various constituents as a function of temperature and oxygen concentration. The computer program was specifically applied to reactions pertaining to the corrosion of superheater tubes in pulverized coal-fired boilers; however, it is useful for any multicomponent, multireaction scheme in which equilibrium constant data can be obtained and is comprised of gaseous reactants along with finely dispersed solids or liquids. General applicability of the computer program, including its limitations, are discussed along with detailed instructions for using the program.

Jan 1, 1973

By S. R. Krogh, T. O. Olsen

Analytical expressions for the breakage rate as functions of mill charge, mill speed, particle size, ball diameter, and ball load are derived, using idealized models for probability of breakage (Gaudin and Meloy), energy distribution (Mempel), and arithmetic mean of effective ball energy (Langemanns). Computational results using the theoretical equations are compared to experiments. The equations enable simulation of ball mill grinding at different grinding conditions.

Jan 1, 1973

By Ernest M. Spokes, Martin A. Thieme

A simulation model developed to analyze scraper-pusher utilization in open pit mining systems is described. The mining simulator discussed was developed as a tool to aid management in evaluating alternative open pit haulage schemes and to reduce the risk involved in the selection of equipment.

Jan 1, 1973

The application of biogeochemical methods in mineral exploration in semi-arid to arid environments in Western Australia has been investigated in an area near Norseman.The study involved a comparison of trace element characteristics of rock, soil and plants in the vicinity of the Pioneer BB prospect, where nickel-iron sulphide mineralization occurs in a "greenstone" sequence of ultrabasic, basic and sedimentary rocks.Analyses of unweathered and partly weathered rock from diamond drill cores show the ultrabasic rock to be highly variable with respect to Ni, Cu, Co, Zn and Mn.Samples of weathered bedrock and overlying soil were analysed for total trace element contents and for the trace elements associated with secondary iron and manganese oxides. Approximately 30 per cent of the total nickel content of the weathered basic rock is associated with secondary iron and manganese oxides, compared with approximately 15 per cent in the weathered ultrabasic rock.The soil has a sufficient residual content to provide a reliable indication of the chemistry of the underlying rock. Total trace element analyses of the -89 mesh fraction show strong anomalies for nickel and copper over the mineralized zone. Important amounts of nickel, cobalt and, to a lesser extent, copper are apparently associated with secondary iron and manganese oxides in the soil.Melaleuca sheathiana (tea tree) has been used to study the relationship between soil and plant chemistry. No strong relationship between plant and rock type was observed. Analyses were made of leaves, twigs, wood, bark and roots, and all plant organs were found to have anomalous nickel and copper contents near the mineralized zone. Leaves were found to give the best contrast in the anomalous area and to show fewer erratic values than other organs. It is concluded that the uptake of trace elements by tea tree is low in the semi-arid to arid environment of Western Australia, but that analyses of the plants do reflect the presence of mineralization.

Jan 1, 1973

By F. E. Joyce

This paper describes the development of a process for producing manganese and iron pellet concentrates from low-grade manganiferous iron ores of the Cuyuna range by a two-stage sulfatization-reduction roast. First, the manganese minerals (7.5 percent manganese) were converted to water-soluble manganese sulfate by roasting in sulfur oxide gases at 700° C, then, the hematitic iron minerals (31 percent iron) in the hot sulfatized are were reduced to magnetite with simulated reformed natural gas in the temperature range of 350° to 425° C. Batch tests were made in a 3-inch-ID by 6-inch-long, gas-heated, stainless steel retort, and continuous countercurrent experiments were performed in a 2-inch-ID by 10-foot-long, electrically heated shaft furnace. Manganese sulfate was removed from the roasted product by leaching with water, and over 90 percent of the manganese was recovered in an oxide product (65 percent manganese) obtained by precipitation, drying, and thelmal decomposition of the sulfate. An iron oxide concentrate (60 percent iron) with an iron recovery of 75 percent was obtained from the water-insoluble residue by magnetic separation.

Jan 1, 1973