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By T. C. Rao, Deb Kanungo

"The results of tests carried out on a 3-in. hydrocyclone have shown the linear relationships that exist between: (1) the flow-rate of water in the feed to and the overflow product from the cyclone; (2) the flow-rate of solids in the feed to and the underflow product from the cyclone. The underflow size distribution of an operation has been found to be linear and its usefulness in evaluating particle distribution in the cyclone has been discussed. Effects of design and operating variables on the above relationships have been discussed. The performance of this 3-in. hydrocyclone has been compared with that of a 20-in. cyclone, the results for which are available in the literature."

Jan 1, 1973

Transport technology has produced social changes since the invention of the wheel five millenna ago when man was freed from the need to expend large amounts of energy to move goods and people. Further impetus came with the Industrial Revolution when mechanical power producing devices were applied to land and-water transport. This leap, together with the application to air transport has caused enormous social changes in our way of life. The state of technological advancement of transport modes has dictated to a large degree the develop- ment of Australia and Papua New Guinea. It is suggested that we should not make advances for technology's sake but examine the real needs of the users of transport and ensure that the un- necessary costs are not incurred. The transporting techniques for the ore, waste and slurries used by Bougainville Copper in Papua New Guinea are, in general, quite conven- tional but the scale of operations and the location has modified some modes. in particular the soft' overburden and concentrates were slurried for trans- port and the lack of experience in humid climates restricted the choice of the mine haulage truck. The near future of the transport. industry is seen as an expansion in equipment sizes but the suggestion is made that we need to examine more than the economic and technical aspects; it is necessary for the social con- sequences of our actions to bear examination by outside opinion

Jan 1, 1973

By L. L. Oden

The purpose of this research was to develop a method to remove copper and tin from the magnetic fraction of incinerated municipal refuse, as recovered by the Bureau of Mines pilot plant in College Park, Md. Copper, present in the scrap in a metallic form bonded to ferrous objects, was amenable to leaching in cupric ammonium carbonate solution. Copper levels in small 5-to 10-lb lots of treated scrap were reduced from the initial level, 0.5 to 0.6 pct, to 0.1 to 0.2 pct. Larger lots of scrap (100 lb) were treated less effectively because of poor contact of solution and scrap. Oxidation in the air or in aerated aqueous solution was applied to liberate tin from the dilute solid solution present on the surface of incinerated tinplate. Shredding of air-oxidized scrap or caustic leaching of scrap oxidized in solution reduced tin levels from the initial 0.25-pct level to about 0.1 pct.

Jan 1, 1973

By Joan C. Biordi

A molecular beam-mass spectrometer-low pressure flat flame apparatus has been constructed for the purpose of examining the chemical microstructure of normal methane-oxygen-argon flames and those inhibited with Halon extinguishants. Details of construction and performance of this apparatus and of related flame temperature measurements are given. Particular attention is paid to the empirical characterization of the perturbation to the flame caused by the sampling probes. The composition profiles obtained for normal flames are compared to those of flames inhibited by CF3Br. In addition to the usual stable species (CH4, O2, CO, CO2, H2O, H2, and H2CO), the inhibitor, its products and intermediates associated with its reactions could be followed. In particular, hydrogen bromide, bromine atoms, hydrogen fluoride, and carbonyl fluoride were observed. The relatively rapid disappearance of inhibitor and early appearance of fluorinated reaction products suggest a short lifetime for the CF3 radical in this system. Observation of COF2 suggests that CF3Br is effective as an inhibitor, at least in part, by virtue of its interference with the oxygen containing species of the normal chain reaction. Profiles of the 17+ peak at low electron energy suggests that the hydroxyl radical may also be sampled, but the profiles obtained are not yet sufficiently accurate to determine the effect of inhibitor on this important flame radical.

Jan 1, 1973

By Donald S. Macdonald

"I AM thankful for this opportunity to address the Toronto Branch of The Canadian Institute of Mining and Metallurgy. The Members of your Institute can have a great influence on the direction in which the mineral policies of Canada will evolve, and to assure that optimum benefits from our country's vast mineral resources will accrue to the nation as a whole and to all its citizens. Today, I want to: (1) offer an outlook on the mineral industry for 1973; (2) talk briefly about the role of minerals in the total economy; and (3) outline some of our thinking with respect to a national minerals policy for Canada."

Jan 1, 1973

By R. S. Boorman, H. G. Ansell

"Poor separation of lead from a copper concentrate of a major base metal producer was thought to have resulted from copper (0.2-0.4%) in the galena which caused it to float with chalcopyrite. No inclusions of copper mineral were detected which could account for the flotation of galena. The tendency for copper-bearing galena to float with chalcopyrite was confirmed by Hallimond-tube experiments in which the floatability of copper-doped synthetic galena (0.1-0.4% Cu) was approximately four times as high as copper-free galena. The difference in the cell edge (5.9338 ± 0.0003 A, Cudoped galena; 5.9361 ± 0.0002 A, Cu-free galena) indicated that the copper was lattice-bound and did not occur as submicroscopic mineral inclusions."

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 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 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

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 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

By Robert M. Cox

Systematic roof bolting has proven to be a very effective method of mine roof control; however, major roof failures still occur and roof falls still remain the number one occupational hazard of underground miners. Why do some bolted mine roofs fail, while the vast majority of bolted mine roof remains stable and safe to work under? Observations of numerous roof failures indicate that most of the major roof failures* are associated with either: 1) Jointing, faulting or other structural fracture zones; 2) massive shale beds of lenticular structure, or 3) thinly laminated sand-shales. The jointing and faulting present an obvious weakness in the roof rock structure; whereas, the massive shales and laminated sandy-shales create a roof structure with low shear strength and/or modulus of deformation. An observation of major significance is that most bolted mine roofs fail as a unit, and that the thickness of the fall is roughly equivalent to the roof bolt length (See Figure 1). In fact, several operators have experienced the phenomenon of an increase in roof fall thickness with an increase in roof bolt length.

Jan 1, 1973

By Primak. George J.

"In the development of a new product as well as during its introduction on the market, it is very important to give due consideration to problems involving patents, licenses and trade marks. At the very beginning of the research and development program, it is obviously essential to ascertain, through a suitable patent search, that the product in question will not infringe any patents which are still in force. Then, a possibility of achieving one's own patent or proprietary position on the product or the process of its manufacture should be carefully explored. Licensing arrangements that one may reach with respect to patents and know-how covering such new product may, in the final analysis, determine its over-all success or failure. If one can count on licensing revenues or some favourable cross-licensing arrangements with respect to a newly developed product, this may go a long way to achieving profitability and success. The selection of a good trade mark is probably one of the most important acts that one has to perform once the product is developed, as customers will identify the new product by such a trade mark. In many instances, successful marketing and widespread acceptance of a product are largely due to its appealing name or trade mark, accompanied by proper promotion and advertising. Once the trade mark has been adopted, it should be registered in the Trade Marks Office to provide the protection afforded by federal statute. If the product is to be manufactured, sold or licensed in some other countries, similar considerations should be made with regard to each such country."

Jan 1, 1973

By Reynold Q. Shotts

One often sees in the papers, in these days of ecological consciousness, estimates of the quantity of land that has been "devasted," "ruined," or "destroyed," by surface or strip mining, especially for coal. One feels sure that coal miners must have been the first to discover the art of excavation and that the public didn't know of its existance until five or 10 years ago! Estimates of the acreage vary widely with most of them sounding somewhat unreal. One estimate of 175,000 acres in Alabama appeared in one newspaper article and the implication was that all of this was mining for coal. The question was raised anew last summer when the author began working on a land use estimate utilizing aerial photographs, a preliminary project to the Alabama Earth Resources Technology Satellite (ERTS) contract presently being fulfilled. One land use category was barren or waste land and aside from some sand beaches in the two coastal counties in Alabama, recently strip mined land constituted most of that category. It quickly became apparent that old stripping was very hard to detect so that estimates from aerial photographs are not accurate. With regard to relatively new stripping, a thin veneer of reflective dirt washed over the countryside may result in a considerable overestimate of the excavated area. Actually, there is a way to estimate the area excavated by strip mining using published Bureau of Mines figures. At least three sets of data are needed: (1) Coal production figures, (2) average thickness of coalbeds mined, and (3) an accurate recovery figure.

Jan 1, 1973

By C. M. McCulloch

A geologic study of Mines 32 and 33 in Cambria County, Pa., was conducted as part of a methane control research program. Areas of high methane emission and roof instability are encountered which are related to the structural and stratigraphic features that characterize the geologic setting of these mines. Locally the folds trend N 20° E ±2°, the direction of the butt cleat in the Lower Kittanning coal. The face cleat strikes at N 69° W ±2° and the systematic rock joint in the surface bedrock strikes N 67° W ±2°. This suggests that a directional stress oriented N 70° W produced the folds and influenced the directions of coal cleat and systematic joint sets. Analysis of SLAR indicates three directions of prominent regional lineation: N 39° E, N 31° W, and N 70° W. Little gas was encountered during development mining; large volumes of gas are encountered when roof falls. Most of the gas comes from strata above the mined coal; therefore, to control methane, roof instability must be controlled. Roof falls and high rates of methane emission are most likely where less than 30 feet of many thin layers of limestone, shale, and sandstone occurs between the Lower Kittanning coal and the next coal and in zones along the margins of a sandstone channel.

Jan 1, 1973

By John M. Heckard

It all started with the National Environmental Policy Act of 1969, which establishes that Congress is committed to restore and maintain environ- mental quality. It directs all federal agencies to identify and develop methods and procedures so that environmental parameters and values will be given equal consideration in the decision-making process, along with economic and technical parameters. Section 102 of the Act directs, among other things, that all agencies will submit a detailed statement on: (1) the environmental impact of the proposed action, (2) any adverse environmental effects which cannot be avoided should the proposal be implemented, (3) alternatives to the proposed action, (4) the relationship between local short term uses of man's environment and the maintenance and enhancement of long term productivity, (5) any irreversible and irretrievable committments of resources which would be involved in the proposed action should it be implemented. Passage of this act has been followed by other legislation, both federal and state. The Water Quality Act of 1970 puts teeth into the previously existing Federal Water Pollution Control Act by requiring a "certificate of reasonable assurance that the activity licensed will not violate the applicable water quality standards." The Clean Air Act of 1970 requires that the Environ- mental Protection Agency establish national air quality standards, as well as standards for significant new pollution sources.

Jan 1, 1973

By F. Robert Hollo

Programmable controllers have achieved remarkable acceptance over the relatively few years since their introduction. They provide some unique advantages over conventional relay and solid-state logic, which they often replace. Programmable controllers are discussed in both conceptual and functional terms, followed by an exploration of their applicability to material handling tasks with particular emphasis on conveyor systems.

Jan 1, 1973

By J. S. Brock

Magnetic, electromagnetic and gravimetric surveys have played an important role in the mineral exploration leading to the discovery of three major massive sulphide deposits in the Anvil-Vangorda area of the Yukon Territory. During 1964 and 1965 a saturation prospecting program, relying heavily on the integrated use of airborne and ground geophysical survey techniques, led to the discovery of the Faro deposit, which was subsequently proven to be a 63-millionton lead-zinc orebody. Locating the Faro deposit, the largest found to date in this overburden-covered region, involved an exploration sequence requiring the selection of a favourable geologic environment, aeromagnetic and electromagnetic surveys, property acquisition of anomalous areas and detailed ground geophysical surveys, followed by rotary drill testing, detailed gravimetric surveys and diamond core drilling.

Jan 1, 1973

By R. Tervo, G. Ellie

"Automated information systems are being developed very rapidly in Europe. In France, Belgium and West Germany, more than 70% of the coal production is controlled by these installations. Information on both product ion and the mine environment is produced. For example, at one mine in France the system records the operating times of the compressors and of the refrigeration pumps, counts the number of coal cars passing the unloading point, and controls the principal conveyors and the loading /unloading of the storage bins. In addition, the ventilation air velocity, the methane content and the carbon monoxide content in the return air entry are recorded; an alarm is triggered and the current to the conveyors cut when the gas content exceeds a critical level. The recorded information is used at four levels: (1) for immediate action, (2) for daily reports, (3) for monthly reports and (4) for long-term studies. For example, when any conveyor is stopped for more than 10 minutes, the system controller immediately telephones to learn of the reason. At the end of a shift, the load factor of the conveyors is computed; then monthly an analysis of the causes of low load factors is made. The presentation describes in detail the system that has been installed in more than 20 mines in France."

Jan 1, 1973

By David W. Houston

The increasing energy crisis, coupled with stringent environ- mental regulations, has created new demands for high capacity materials handling systems with unit train transporting and continuing surveillance of quality control. Effective and efficient methods of material conveyance are through high speed, high volume conveyor belts with the monitoring of quality through the utilization of automatic sampling. When we speak of high speed, high volume belt discharges we are referring to speed ranges from 600 to 750 FPM and volumes as high as 5500 TPH. To achieve the optimum operating sampling system for high capacity belt discharges, it is imperative that two major design characteristics be investigated and evaluated; namely technical analysis of operating conditions through application of ASTM design criteria and practical experience in the selection of equipment and the design of related components. The task of obtaining a sample of reasonable weight to represent an entire lot presents a number of problems and emphasizes the necessity for using standard sampling procedures.

Jan 1, 1973