Search Documents

By D. M. Richards

"IntroductionThe Highland Valley Copper partnership was formed in July 1986 as a logical result of a mine with a large ore reserve but a small mill, and a mine with a large, modern mill but dwindling ore reserves. The original partnership of Cominco and Rio Algom was expanded in January 1988 to include Highmont Mining Company. During 1988/89 the Highmont mill was moved 7.5 km to adjoin the Lornex mill, becoming the Highland mill in the process, with a nominal capacity of 130 000 tonnes per day.The mine is located near the town of Logan Lake, 220 km northeast of Vancouver, British Columbia and 55 km southwest of Kamloops. The map in Figure 1 shows the general area. Kamloops is a major service centre and is served by two railways, two major roads and a regional airport. The mine site is situated between 1200 m and 1600 m above sea level on the Thompson Plateau. Principle activities in the area, in addition to mining, are cattle ranching and forestry. Ore reserves at the beginning of 1996 totaled 533 million tonnes at a grade of 0.42% copper and 0.008% molybdenum. Ore is mined from two pits — Valley, 3 km northwest of the mill; and Lornex, 1 km southwest of the mill. With 78% of the reserves, the Valley pit is the focus of activity.In order for Highland Valley Copper to remain competitive with a very low grade ore reserve, it has been necessary throughout the mine’s life for new technologies to be embraced as they become available. These have included such diverse technologies as in-pit crushing and conveying, large mechanical drive trucks, computerized truck dispatch and oneman survey instruments. During the next few years, it is planned to introduce two further technologies that are relatively new to both the world at large and the mining industry in particular. These are namely Global Positioning Systems (GPS) and Geographical Information Systems (GIS), both of which are expected to have a major impact on the way mining is carried out in the years to come."

Jan 1, 1997

By Alireza Sarafi, Alijan Aftabi

"A hydrocyclic system used for mineral separation at the laboratory scale results in the separation of more than 90% of micas. The system functions only by water and might offer advantages where other methods of mica separation are not available. INTRODUCTIONVarious methods for the separation of micas, wollastonite, and garnet, e.g., screening, flotation, magnetic separation, and heavy liquids, are well known (e.g., Spence, 1929; Bates,I960; Gillson et al., 1960; Benjamin, 1971; Connor and Kolhnar, 1991; Collings and Andrews, 1991). However, where these methods are not available, the separation of micas by a hydrocyclic system developed by Sarafi and Aftabi (1991) may prove to be economic. This note is a brief description of the hydrocyclic system. Minerals and MethodFor testing the recovery of mica and other minerals from different rocks (garnet-mica schist, skarn, and pegmatite), standard minerals were tested first, and then rock samples. Pure mineral standards were prepared from coarse-grained samples of pegmatite, mica schist and skarn; the grain size of the minerals separated was more than I cm. The Hydrocyclic System and Mineral SeparationThe hydrocyclic system is shown schematically in Figure 1. In the first step in mineral separation, mineral and rock samples were crushed, milled, and then sieved to minus 250 plus 125 microns. Approximately 10 gm to 25 gm of the sample were inserted in decanter Dt • The motor pwnps, M1 and M2, were then turned on and the water valve rl was opened. At this time, water was flowing turbulently (30 em3/sec. to 50 em3/sec.) and minerals were separated according to their crystallographic nature, density and!or habit. The fInal separation was done by exit valves r2, r3 and r4, while the motor pwnps were still operating. After each experiment, the rt , r2' r3 and r4 valves were closed and the motor pumps were turned off. Following this, minerals in each decanter and the mter were collected, dried and weighed. The whole time of the experiment was optimized to be about 10 minutes, but varied from 3 to 15 minutes for micas and garnets. respectively."

Jan 1, 1994

By C. W. Vaupell

The Huitzuco mines lie in north central Guerrero, Mexico; production has been about 90,000 flasks of quicksilver since 1873. Near-surface ores fill extinct mud geysers and the deep deposits are chambered veins, stock-works in brecciated blocks, and replacements in limestone. The epigenetic minerals livingstonite, stibnite and sulphur occur in limestone, gypsum and dolomite through a developed vertical range of 260 meters. The deepest workings expose an increased amount of stibnite, which probably indicates that the lower limit of mercury mineralization is being approached. A resurgence of heat and water formed geysers over an extended area after the period of mercury mineralization. Mud geysers, which are situated, in the outcrops, contain the secondary mercury minerals, cinnabar and barccnite in the gravel and mud filling the vents. A 150-ton flotation plant is in operation concentrating stope fills that assay 3.0 kg. of mercury per ton. In one open stope, which is more than one hectare in area and 60 m. high, 150,000 tons are available. Introduction The Huitzuco mercury mines are of interest because of the unusual occurrence of ore in extinct geyser vents and the presence of several rare mercury minerals. Some of the deposits have typical characteristics of the telethermal zone and there is a gradation towards typical epithermal mineralization in depth. Halse,1 Villarel1o,2 Mactear3 and Merri114 have described the geology and the early operations in the district, and Bar-cena5 and Mallet6 have described the rare mercury minerals, livingstonite and barcenite, found at Huitzuco. Location The village of Huitzuco lies in the north central part of the State of (Guerrero, Mexico, 27 km. (16.7 miles) east of Iguala, which is the largest and most important town in the area. Iguala is served by the Mexican National Railways and also by the Mexico City-Acapulco highway. The highway is surfaced from Mexico City to Iguala, a distance of 200 km. (124 miles) by road, and there is a fairly good, level, dirt road from Iguala to Huitzuco. The elevation above sea level is about 1000 m. (3280 ft.). The climate is warm and very dry except during the rainy season, from June to

Jan 1, 1941

By C. W. Vaupell

The Huitzuco mines lie in north central Guerrero, Mexico; production has been about 90,000 flasks of quicksilver since 1873. Near-surface ores fill extinct mud geysers and the deep deposits are chambered veins, stock-works in brecciated blocks, and replacements in limestone. The epigenetic minerals livingstonite, stibnite and sulphur occur in limestone, gypsum and dolomite through a developed vertical range of 260 meters. The deepest workings expose an increased amount of stibnite, which probably indicates that the lower limit of mercury mineralization is being approached. A resurgence of heat and water formed geysers over an extended area after the period of mercury mineralization. Mud geysers, which are situated, in the outcrops, contain the secondary mercury minerals, cinnabar and barccnite in the gravel and mud filling the vents. A 150-ton flotation plant is in operation concentrating stope fills that assay 3.0 kg. of mercury per ton. In one open stope, which is more than one hectare in area and 60 m. high, 150,000 tons are available. Introduction The Huitzuco mercury mines are of interest because of the unusual occurrence of ore in extinct geyser vents and the presence of several rare mercury minerals. Some of the deposits have typical characteristics of the telethermal zone and there is a gradation towards typical epithermal mineralization in depth. Halse,1 Villarel1o,2 Mactear3 and Merri114 have described the geology and the early operations in the district, and Bar-cena5 and Mallet6 have described the rare mercury minerals, livingstonite and barcenite, found at Huitzuco. Location The village of Huitzuco lies in the north central part of the State of (Guerrero, Mexico, 27 km. (16.7 miles) east of Iguala, which is the largest and most important town in the area. Iguala is served by the Mexican National Railways and also by the Mexico City-Acapulco highway. The highway is surfaced from Mexico City to Iguala, a distance of 200 km. (124 miles) by road, and there is a fairly good, level, dirt road from Iguala to Huitzuco. The elevation above sea level is about 1000 m. (3280 ft.). The climate is warm and very dry except during the rainy season, from June to

Jan 1, 1941

By R. J. Hamilton

Considerable success has been achieved in recent years in reducing concentrations of respirable dust in UK coalmines; thankfully this has been reflected in significant improvements in pneumoconiosis statistics. However, continuous increases in mechanisation and in rates of working, accompanied by more stringent dust regulations, necessitate the introduction of improved and often more sophisticated methods of dust control. The increased application of exhaust ventilation and air cleaning techniques seems likely to be the most important step forward in dust control in coalmining during the next few years. A typical drivage in a UK mine is not more than 16 ft (5 m) wide and is supported by steel arches. In the past the majority of such roadways were driven by the conventional means of blasting and loading. Since the main purpose of ventilation was to clear blasting fumes and to provide adequate scouring of firedamp, not surprisingly it was usual to have 'forcing' ventilation. Present systems of operation are making increasing use of heading machines and it is not surprising that well over half of all drivages are now ventilated by exhausting methods. (1) The great majority of coal getting in the UK is from longwall faces, usually in seams of less than 6 ft (1.8 m) thickness. Although this method of min¬ing has many advantages in terms of safety and productivity, dust control is made more difficult because of the need for men and machines to work in the same ventilation stream. Much emphasis has been placed on improving the design and methods of opera¬tion of longwall machines to reduce dust production, and improved ventilation has provided greater dilution, and in consequence, reductions in dust concentration. On all machines water is now fed through internal galleries to the cutting elements. Unfortunately, one of the difficulties associated with mining thin seams is that there is some unavoidable cutting in the roof or floor and in many seams there are faults to be traversed and dirt bands which must be removed with the coal. Under these conditions it appears that the use of exhaust ventilation and air cleaning offers the most promising way of achieving satisfactory dust conditions.

Jan 1, 1980

By Paul A. Farrar, Felix Ermains, Harold Margolin

The systems Ti-Crand Ti-Vhave been reinvesti-gated in the region up to 40 wt pct alloying addition using both conventional and rapid quenching techniques. The Ti-Cr eutectoid temperature was determined to be at 667° & 10° C and 14.5 wt pct Cr. The solubility of the Cr in a Ti was found to be less than 1 pctat 700"C. The P transus of the Ti-V system was found to be depressed to 510°C at 40 wt pct V and the solubility of V in a Ti was found to be less than 2 wt pct at 700°C. Investigation by a. d. McQuillan1-3and m. k. McQuillan4 on the systems Ti-Co, Ti-Cr, Ti-Cu, Ti-Fe, Ti-Mn, Ti-Ni, and Ti-V has cast doubt as to the position of the ß/a + ß boundaries in many of these systems. Their investigations were carried out using hydrogen pressure and/or rapid quenching experiments, as opposed to the conventional quartz capsule techniques employed by most other investigator.'" By these methods, the ß/a + ß boundary was found to be lower than that obtained by conventional techniques in all except the Ti-Fe system. In the latter, the ß/a + ß boundary was essentially the same as the boundary obtained by conventional technique.7' On the basis of rapid quenching results in the Ti-Cr system, M. K. McQuillan4 placed the eutectoid temperature below 550°C whereas other investigations using conventional techniques had placed the eutectoid variously as between 650' and 700°C,5 between 675' and 700°C,6 between 650" and 675°C,7 at 670°C,8 and above 625"C.la9l3 In order to check these results, a reinvestigation of four of the systems was undertaken using both conventional and rapid-quenching techniques. The Ti-Fe and Ti-Mn systems will be dealt with in anoth er paper, with only the Ti-Cr and Ti-V systems being discussed here. EXPERIMENTAL TECHNIQUES Alloys employed for the delineation of the systems under investigation were prepared from iodide titanium sheet capsules containing the alloying materials,

Jan 1, 1962

By J. Lu, M. Mohammadi, C. Pelletier, B. Wassink

Chemical reduction of selenate by chromous ions is proposed as a novel method to remove selenate from sulfate-bearing solutions Chromous ions were generated by electrochemical reduction of chromic ions using an electrochemical cell. The investigation was conducted in sulfate medium and under various concentrations of chromous ions (0.0062 to 0.05M), pH 1 to 2.2 and temperature 10 to 60°C. Selenate ions were rapidly reduced by chromous ions to hydrogen selenide. The overall reaction at a chromous/selenate molar ratio of 8 or higher can be expressed by the following reaction. At an initial chromous/selenate molar ratio below 8, the products are hydrogen selenide and elemental selenium. At a lower chromous/selenate molar ratio and pH, more elemental selenium and less hydrogen selenide are produced. The reduction kinetics is controlled by both chromous ion and hydrogen ions concentrations. The reaction rate is first order with respect to selenate, hydrogen ion and chromous ion concentrations. It was found that the selenate reduction rate with chromous is independent of the concentration of sulfate present in the solution. The general rate equation was proposed and the rate constant was calculated as k= 0.38 M-2s-1. An activation energy of 58.7 kJ/mol was obtained in the temperature range from 10 to 50°C. Nearly 100% of selenate can be reduced to H2Se from solution containing 17 ppm selenate in less than 30 minutes at pH 2.2 and 60°C. Various strategies have been tested to remove the produced H2Se from solution. INTRODUCTION Selenium in nature is mostly associated with metal sulfide minerals such as copper, iron, zinc, and lead sulfides (Zingaro & Cooper, 1974). The extraction of metals from ores has the potential for selenium contamination of ground and surface water which can pose an environmental and health concern. Therefore, selenium contamination in the receiving environment is a key issue for many industries (specifically copper industry) and the treatment of wastewater contaminated with selenium is a growing challenge. The effective removal of selenium from contaminated water is very important to support sustainability in the copper industry and the other industries with selenium pollution issues.

Jan 1, 2019

[Admissions: H. J. Gruy, Chairman Kenneth W. Robbins W. Frank West Aurel E. Smith R. F. Madera Tom G. Calhoun Kenneth F. Anderson B. M. Goltlieb Advertising: Clark R. Edgecomb, Chairman Bernard F. Klein. Henry N. Lyle R. E. Howard H. M. Krause, Jr. Education: R. L. Whiting, Chairman John M. -Campbell E. T. Guerrero Don D. Little J. C. McCarthy Frank G. Miller Douglas Ragland H. C. Slider R. L. Slobod]

Jan 1, 1961

By M. Albertson

AT Cobalt, Ontario, Canada, a lake was drained to facilitate mining, by the Mining Corpn. of Canada, during the spring and early summer of 1915. Previous to pumping out the water, great quantities of sands and slimes from concentrating plants had been discharged into the lake and during and after the lake's drainage, its basin' Was a receptacle for tailing products. As the writer was at work along the shore line as the lake was being drained, he had a good opportunity to observe the changes that took place as the water was withdrawn. Some adjustments between the incoming sands and the mud in the lake had taken place before pumping was commenced. One of the most interesting results was the appearance of a small dome in a path the writer traversed twice a day for several months; he remembers distinctly the difficulty of crossing this. Cobalt Lake owed its existence to the gouging out of a rock basin by glaciation. The long axis of the basin closely follows the strike of a thrust fault of about 500 ft. (160 in.) vertical displacement. The lake was originally shaped somewhat as shown. The length was about 3000 ft. (914.4 in.), the width at the lower lobe was about. 1000 ft., and the, width at the narrows probably. 400 to 500 ft. The original depth of water varied from 20, to 30 ft. (6.1 to 9.1 m.), near where the island later was formed, to 60 to 70 ft. (23.6 to 27.6 m.) in the widest part of the lower lobe. At the narrows, the depth was 30 to 40 ft.. Above the bed rock was sand, with boulders near the bottom, and mud. During the building of the railroad in 1903, considerable filling was done along the right of way. With the commencement of mining operations, about 1905, waste rock and mill tailings were dumped into the lake. One of the mining companies operated a hydraulic giant to remove the glacial debris from several hundred acres of rock surface; much of the sand and clay from this operation was deposited in the. lake. About

Jan 2, 1921

T. R. HARRISON, Washington, D. C. (written discussion). *-Mr. Kowalke shows that a high resistance millivoltmeter is subject to smaller errors, due to change in resistance of the thermocouple to which it is attached, than is a low-resistance instrument. He uses as examples instruments having resistances of 30 and 2 ohms, respectively. At the Bureau of Standards, resistances above 300 ohms would be considered high and 30 ohms rather low. In the tests on calorized-iron thermocouples, a difference between the first and third calibrations of the couples serves to show changes due to the intermediate heat treatment and only under certain conditions would changes in calibrations due to changes in the wire be detected by ,a recalibration after 1 1/2 in. had been cut from the hot-junction end of the couple and the ends rewelded. The calibration of a couple depends only on the thermoelectric prop-erties of that part of the couple which lies within the region of non-uniform temperature, i.e., the temperature gradient; hence, so long as the temperature gradient falls along wires of similar thermoelectric properties no change in the electromotive force is produced by altering the metals of those parts of the circuit that are at uniform temperature. Usually at the cold-junction end of the circuit, copper leads, brass binding posts, manganin resistance coils, and various other materials form part of the circuit, but so long as all are at a uniform temperature (or if for each junction between unlike metals there is a similar opposing junction at the same temperature) no resultant thermoelectromotive force will be produced thereby. Likewise, if a length of several inches at the hot-junction end of the couple is at uniform temperature, it matters not if this section is unlike other parts of the couple, so long as there is good metallic connection and no source of e.m.f. other than thermoelectric is present. Cutting off part of the hot end of the couple within such a region of uni-form temperature would not alter the e.m.f. of the couple.

Jan 12, 1919

By G. P. Schoonraad, J. E. Clay

Treatment of zinc silicates by the Waelz Process by J. E. CLAY (M.I.M.M.) (Visitor) and G. P. SCHOONRAAD. Pr. Eng.. B.Sc. Eng. (Rand) (Member) A review is given of the Waelz process. The chemistry of the process and the mechanism of crust formation (accretions) are briefly dealt with. The plant of Kiln Products Limited and its operation are described. The problems encountered and methods for their elimination are presented.

Jan 8, 1976

By M. Albrecht

I have been following the discussions on coal degradation started by the article "Degradation process in coal slurry pipe-lines," by M.G. Ayat and B.C. Scott. I agree with Mr. Dasher's comments in January that the title of the article was perhaps misleading as the information appeared to pertain more to processing the coal than to transportation. Specifically, the authors' conclude that the cyclone had an important impact on the degradation. Dr. Ferri's comments on degradation in other physical processes was very correct, handling of coal in a turbulent manner has an impact on the size distribution of the coal. This is one reason that when I design a coal system (mine to rail car) I try to minimize the total number of transfer and processing steps consistent with achieving the desired product specifications. Another area, mentioned in passing in the article, the impact of natural causes and the mining step, is of particular interest to me. A mine in West Virginia had a variation of 50% in the -6.35 mm (-0.25 in.) raw coal depending upon the direction of mining. Since it was a single unit mine, this significantly impacted the final product. Two articles on mining's impact on size distribution are: • Stefanko, R., Chopra, 1K., and Ramani, R.V., 1974, "Mining influence on size consistency and washability characteristics of coal," SME Fall Meeting, September; and • Albrecht, M., and Olsen, D., 1980, "Mining methods impact on coal preparation plant design," 1st International Mine Planning and Development Symposium, September. Both articles presented information on variation of size distribution and cleaning plant performance on a coal depending on the mining method used. Both articles considered a single coal seam at one mining operation. Stefanko's article considered continuous and conventional mining of coal in Pennsylvania. Albrecht's article considered surface, underground continuous, and underground hydraulic mining of a coal in British Columbia. Both concluded that mining methods do impact coal characteristics. I agree with Mr. Ayat's comments in reply to Dr. Ferri's discussion, "... degradation is a multi-faceted phenomenon involving many natural and man-made factors." As efforts are being made to produce a higher quality (lower sulfur) coal, this topic becomes even more important

Jan 1, 1989

By Michael J. Messel

W. P. MOULD*—Has consideration been given to the problem of retreating the 4,000,000 ton tailings pile to recover the very considerable amount of asbestos fiber that was lost over the years due to insufficient operation and poor recoveries? Also, what was known about the possible content of chromite and the sulphides of nickel and cobalt? M. J. MESSEL (author's reply)—Consideration was given to the problem but nothing concrete has been done up to this time. W. P. MOULD—I am certain the tail- ings contain a very considerable quantity of fiber, not all of which is in the shortest lengths, because in the milling of talc rock from a neighboring location having a common origin with the asbestos bearing serpentine source of the tailings pile, a concentrate carrying 15 pct Ni and Co in complex sulphides and constituting about 4/10 of 1 pct of the talc rock was recovered. In the belief that the tailings also contained an appreciable content of chromite (then in demand, 1937) it was suggested to the management of the asbestos company that a truck load of the current tailings be sent to the flotation plant of the talc company where it would be put over the concentrating tables in an effort to discover the presence and roughly the percentages of chromite, nickel, and cobalt. Preparations for the test were woefully inadequate and the test was completely snarled up by the surprisingly large quantity of asbestos fiber from 1 in. long down to very short fiber, all of which matted up and plugged launders and pumps with disastrous effects and practically the total loss of the sample. If anything was indicaded by the test, it was that a wet process for milling asbestos was worthy of very serious consideration. M. J. MESSEL—A wet milling process for tailings retreatment only, is at present under study at our plant. One asbestos mining company in Canada has constructed a fairly large test plant for this purpose, but as yet no definite results have been obtained other than in a small test unit plant which were in some respects quite encouraging.

Jan 1, 1950

IN welcoming the attending members of the Ameri-can Zinc Institute's Ninth Annual Meeting to St. Louis on April 18, the president of the Chamber of Commerce stressed the notable progress that had been made during nine years, marked by many price de-pressions and internal dissensions, while controversies between miners and smeltermen threatened to wreck the organization, prices dropped, and consumption grew languid for want of organized publicity and research. The reports and recommendations of Percy B. Butler, chairman of the Adjustment Committee, and F. C. Wallower, chairman of the Galvanizing Committee, might well be adopted as the institute's objectives. In reply to the speeches of welcome to St. Louis, Arthur Thacher reminded the delegates that the cor-ner stone of progress in the mineral industries was laid by the formation of the American Institute of Mining Engineers in Wilkes-Barre, Pa., in 1871, and the dedication of that organization to the exchange of ideas and methods of the winning of metals and non-metals from their crude state. The activities of the American Zinc Institute constitute, he said, a valuable phase of that work. Mr. Thacher forecast the treat-ment of 1 per cent zinc ore. After the reading of the report of the board of directors, in which Scott Turner and Louis Boschern were named as honorary members of the institute, a survey of world zinc conditions by A. J. M. Sharpe of London was presented. He held pres-ent conditions in China responsible for much of the present depression in zinc. World stocks on, April 1, 1927, were estimated as 52,900 metric tons. Adolph Boldt's paper on "Solidarity in Industry" was followed by a survey of the Tri-State district by Otto Ruhl, who emphasized the importance to the dis-trict of the organization of the Tri-State section of the A.I.M.E., which already has 135 members and asso¬ciates. He also mentioned .that flotation in the Tri¬State field is adding 1500 tons of concentrate to the weekly production. "Mining Economics" was the subject of Julian D. Conover, secretary of the Tri-State Zinc and Lead Ore Producers Association. He gave a detailed report on the costs of mining and milling in the district.

Jan 5, 1927

By R. W. Barbaro, R. V. Ramani, K. V. K. Prasad, P. T. Luckie

Discussion by A. Unal Barbaro et al. (1990) implemented a tedious study aimed at delineating the short-scale spatial variability of sulfur in a coal seam. It is not possible, however, to extend their conclusions to any other coal seam or use their in any other fashion, because the background geology was not presented. Nor were the conclusions accompanied by geological interpretations in the paper. In addition, an unfortunate printing error occurred where the total sulfur (determined by High Temperature Combustion) variogram in Fig.3 was duplicated in Fig. 2 instead of the seam height variogram. A more serious error, however, has been committed in the definition of the variable, seam height. What is defined as seam height by Barbaro et al. (1990) is, in essence, mining height, and is not a regionalized variable that should be studied by geostatistical methods directly. Despite the fact that the variable, seam height, is not defined in the paper explicitly, the following quotation discloses the fallacy: "All roof rock that exceeded 1.8 m (6 ft) from the floor was not taken because the longwall was operated to not mine more than 1.8 in (6 ft) unless the coal seam height exceeded 1.8 m (6 ft)." From this definition, the seam height, and therefore the sampling height, is equal to the actual coal thickness, if the coal thickness is greater than 1.8 m (6 ft). Otherwise, it is equal to the sum of the coal thickness plus the thickness of the roof rock that complements the thickness to 1.8 m (6 ft). In the latter case, the seam height is constant and equal to 1.8 m (6 ft). It is possible to conduct a variogram study on a pool of samples that are realizations of two different variables. But the conclusions derived would not belong to any one of the two variables uniquely and, therefore, do not possess any significance. Geostatistical analysis is irrelevant for the sum of multiple regionalized variables formed by arbitrary selections. In a two-seam setting, for example, the mining height, as defined by the thickness of one seam at one location and the thickness of both seams at another location (due to quality and/or minimum thickness considerations perhaps), should not be used in the calculation of one common variogram. The two seams should be modeled separately. They can then be combined according to the specific purposes of the study. On the other hand, if a constant is added to a regionalized variable (to incorporate dilution perhaps), the variogram of the new variable will not change. Barbaro et al. (1990), surprisingly, does not give any geological interpretation of their results despite the fact that most of them can be explained by the origins of sulfur in a coal seam. The presentation of the results of a geostatistical study with no reference to the geology of the deposit is uninformative. It may also be misleading for the potential users of geostatistics, It is not unusual to find nuggets of pyrite in coal seams. In such cases, pyritic sulfur will probably display a spatial structure for only a very small distance that will appear in the experimental variogram as no spatial correlation. This very well known phenomenon is called the pure nugget effect in geostatistics (Journel and Huijbregts, 1978) and perhaps can explain the lack of correlation found for pyritic sulfur content. The lack of correlation found for the total sulfur content may also be explained in the same way because the total sulfur content is dominated by the pyritic sulfur content in this case study. One should notice, however, that the situation may completely be reversed after cleaning the coal. Not all of the inorganic sulfur should be expected to be in the form of pyrite nuggets in a coal seam. It may also be disseminated in the coal seam and it is expected that it follows a certain spatial structure. However, an existing spatial structure may be masked by including a part of the roof rock, rich in sulfides, into the seam thickness in an arbitrary fashion because areas having a sandstone roof sometimes are known to show a higher sulfur content due to the downward percolation of solutions rich in iron sulfides (Clark, 1979). Plants use sulfur in their growth processes. Much of this sulfur is bound organically during peat accumulation and coal formation (Cecil et al., 1978.) This suggests a spatial structure of some sort for the organic sulfur. However, it is not possible to test this hypothesis because the results obtained by the authors for the organic sulfur content are not given in this paper. For this reason, the conclusion that simple average of the nearby samples would provide the best unbiased estimates is questionable for organic sulfur and is not based on any substantial supporting evidence. It is suspected that no spatial structure was detected and this was due to high sampling and laboratory analysis errors. Before concluding that sulfur variability in the seam at the location of study was random, a more detailed study for the disseminated non-pyritic sulfur should have been conducted, not for the sake of scientific curiosity only, but also due to its utmost importance with regard to coal cleaning and emission control. Pyritic sulfur can be cleaned to a considerable extent, whereas organic sulfur can not, making the emission control strategies highly dependent on the spatial distribution of the organic sulfur (Knudsen, 1981). In the light of these facts, one wonders why Barbaro et al. (1990) did not present the results of their study for the sulfate and organic sulfur content. References Barbaro, R.W.. et al., 1990, "Short-Scale Spatial Variability of Sulfur in a Coal Seam,' Mining Engineering, Vol. 42, No. 11, pp. 1267-1269. Cecil, C.B., et al., 1978, "Geology of Ccontaminants in coal," report prepared for Environmental Protection Agency, North Carolina, 123 pp. Clark, W.J.. 1979, "An interfluve model of the upper Freeport coal Bed in part of western Pennsylvania," unpublished MS thesis, University of South Carolina, 57 pp. Journel, A.G., and [Huijbregls], Ch. J., 1978, Mining Geostatistics, Academic Press, London, 600 pp. Knudsen, H.P., 1981. "Development of a Conditional simulation model of a coal deposit," unpublished PhD dissertation, The University of Arizona, 109 pp.

Jan 1, 1992

By C. A. Rawlins

INTRODUCTION Radcont is a program designed by the author of this paper for the industry to use as an instrument for radiation contamination evaluation and ventilation planning system. Radiation in mines are associated with the mining of gold and gold bearing minerals, as uranium and thorium is incorporated in the mining of these minerals. Radiation contamination in South African mines is not a new concept as it was investigated by the Chamber of Mines in the early 1960's and found not to be hazardous at the time. Since some of our mines export scrap metal to customers abroad, it came to light (1991) that some of the scrap metal was radioactive. The authority that oversees the nuclear aspects in South Africa is the Council for Nuclear Safety (CNS). They investigated these matters and found that the mines needed further information regarding radioactive material and the handling of these contaminated materials. As the various mines were licensed (with various conditions incorporated) thereafter, the mines had to do their own investigations as to what extent their properties (Surface and underground) were radioactively contaminated. Some mines were found to be highly contaminated over the years of operation and controlling conditions were installed and measures installed to reduce the contamination levels. One of the conditions when issuing a licence by the Council for Nuclear Safety (CNS), is that a screening survey be carried out to determine the radiation exposure levels and corrective action to be taken if necessary. These surveys must be done by a person trained in the required procedures for such a survey. The person must also measure the risk correctly and assess the results properly. In such a survey, the internal and external exposure levels must be determined to assess the total exposure of persons working in those conditions and take appropriate action if necessary. When doing such a survey, hundreds and more likely, thou- sands of data points are recorded. In order to assess the data recorded, various integrated and difficult calculations need to be made, and takes up enormous amounts of time. (This excludes the interpretation of the results ) The following explanation of the program shows the different parts of such a survey assessment calculations to be done. The paper details the program layout and the different sub- sections within the primary program. It must be stated that the program, as with any other program, is as accurate as the data inserted into the data base. The program and details thereof are given under the following headings: 1. TOTAL EFFECTIVE DOSAGE WITH REGARDS TO: • GME required gravimetric results obtained (mg/m3) • Thick layer or total contamination measured (Bq/m2) • Dry condition surveys with dust loads taken as a Standard l0mg/m3 • Wet conditions survey with dust loads taken as l mg/m3 • Airborne long lived alpha and beta activities as determined by analysis in Bg/m3 • LTD (Thermoluminescent Dosimeter). Results as obtained from the SABS (South African Buro of Standards) are recorded in this section for each month of the year for each individual worker. An average dose is then determined at the end of the year. • Bucket measurements as recorded. • Smear samples (Loose contamination). As determined by Electra or by analysis • Occupational factors for Metallurgical and Engineering occupations in and around the Metallurgical facilities of your mine. • All underground dosage determination and calculations. (Radon and Thoron) 2. INFORMATION REQUIRED WHEN PROGRAM IS INITIALISED: As the program is started, it opens up on the contents page. Here there are various options to choose from, but one is cautioned as a beginner in operating the program, not to perform any tasks before carefully reading these instructions. Firstly, one must go to the 'Information required" pushbutton. Press this button. The information required page is shown where the cursor can be moved to the block where one can enter the specific mines name. To enter a mines name, put the cursor in the block provided and just insert the mines name with the normal keyboard keys and press the enter button on the computer keyboard. To enter the other information required such as Alpha and Beta instrument efficiency, ALI (Annual limit of intake) and probe area, one can either press the 'Data required" button for a dialog box information or enter it manually by just putting the cursor in the block provided and entering as did above. In order to insert all the required information for the pro- gram to calculate the information required, one must proceed further by entering the area names surveyed in the spaces provided. There are 20 spaces to enter 20 different areas surveyed. One must further also provide the amount of days worked in each area (i.8. 250) in the block provided. The de- fault is 250 days. There are also standard information given in the information data page such as breathing rate (1,2 m31h), 8 hours worked per day, 5 days per week and 50 weeks per

Jan 1, 1997

The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. The objects of the Institute are to advance the science and practice of mining and metallurgy, to afford opportunities for the interchange and recording of knowledge of mining and metallurgy and to ensure high standards of professional conduct and competence. Membership benefits include monthly issues of the Journal of the Institute, monthly General Meetings at which papers are read, symposia, excursions to mining and industrial concerns and the use of club facilities at Kelvin House. Technical journals received on an exchange basis are available to members at the Johannesburg Public Library. The current membership of the Institute is over 1,400. Membership applications are accepted from suitably qualified persons and the requirements for entrance to the various grades of membership are summarised below. Members shall be not be less than 30 years of age, shall be university graduates in pure or applied science or shall produce evidence to the satisfaction of the Council that they have successfully completed a co-ordinated course of study in pure or applied science of at least three years' duration at an approved university or institution deemed by the Council to be of equivalent status. Members shall have been employed in senior technical positions in important mining or metallurgical undertakings for at least five years or they shall have practised as mining or metallurgical consultants for at least five years. They shall be practising their profession at the time of application. Entrance fee R4.00; Annual subscription R14.00 (town), R12.00 (country). Letters of designation: M.S.A.INST.M.M. Associate Members shall be not less than 25 years of age and shall be university graduates in pure or applied science, or shall have successfully completed co-ordinated courses of study in pure or applied science of at least three years' duration. They shall have been engaged in work of an approved technical character in the mining or metallurgical industries, of which not less than two years shall have been in positions of responsibility. A candidate shall be practising his profession at the time of his application. Entrance fee R2.00; Annual subscription R12.00 (town), R10.00 (country). Letters of designation: A.M.S.INST.M.M. Affiliates shall be not less than twenty-five years of age, and shall have been engaged in positions of responsibility in, or associated with, the mining or metallurgical industries for periods of not less than three years. If, however, the candidate for admission to the higher grade of Affiliate, is at the time of his application, already a Student member, he need satisfy the Council only that he is, at the time of his application, engaged in a position of responsibility in or associated with the mining or metallurgical industries. In all cases the applicants shall satisfy the Council that they are fit and proper persons to become Affiliates. Entrance fee R2.00; Annual subscription R12.00 (town), R10.00(country). Graduate Members shall be not less than 21 years of age and shall be university graduates in pure or applied science, or have completed co-ordinated courses of study in pure or applied science of at least three years' duration at an approved university or institution. They shall not remain Graduate members after attaining the age of 30 years without the persmission of Council. Entrance fee R1.00; Annual subscription R7.00 (town), R6.00 (country). Students shall be persons not less than 18 years of age who are being educated or trained in a manner approved by the Council, to occupy a technical position in or associated with the mining or metallurgical industries and who, furthermore, shall not have attained the qualification required for a higher grade of membership. They may remain Students until they have obtained the necessary qualifications for transfer to a higher grade of membership, but not after the end of the Institute's financial year in which the attain the age of 28 (twenty-eight) years. They shall then transfer to a higher grade to retain membership of the Institute. The Council may relax the provisions of this clause in such cases as it considers appropriate. Entrance fee nil; Annual subscription R3.00 (town), R3.00 (country). Other. The Council has the power to elect to the grade of Member or Associate Member candidates who may not fulfil all the requirements for entrance to these grades but whose status, professional achievements and practical experience in mining or metallurgy justify such election. Applications. Requests for membership application forms should be addressed to the Secretary: South African Institute of Mining and Metallurgy, p.a. Box 1183, Johannesburg.

The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. The objects of the Institute are to advance the science and practice of mining and metallurgy, to afford opportunities for the interchange and recording of knowledge of mining and metallurgy and to ensure high standards of professional conduct and competence. Membership benefits include monthly issues of the Journal of the Institute, monthly General Meetings at which papers are read, symposia, excursions to mining and industrial concerns and the use of club facilities at Kelvin House. Technical journals received on an exchange basis are available to members at the Johannesburg Public Library. The current membership of the Institute is over 1,400. Membership applications are accepted from suitably qualified persons and the requirements for entrance to the various grades of membership are summarised below. Members shall be not be less than 30 years of age, shall be university graduates in pure or applied science or shall produce evidence to the satisfaction of the Council that they have successfully completed a co-ordinated course of study in pure or applied science of at least three years' duration at an approved university or institution deemed by the Council to be of equivalent status. Members shall have been employed in senior technical positions in important mining or metallurgical undertakings for at least five years or they shall have practised as mining or metallurgical consultants for at least five years. They shall be practising their profession at the time of application. Entrance fee R4.00; Annual subscription R14.00 (town), R12.00 (country). Letters of designation: M.S.A.INST.M.M. Associate Members shall be not less than 25 years of age and shall be university graduates in pure or applied science, or shall have successfully completed co-ordinated courses of study in pure or applied science of at least three years' duration. They shall have been engaged in work of an approved technical character in the mining or metallurgical industries, of which not less than two years shall have been in positions of responsibility. A candidate shall be practising his profession at the time of his application. Entrance fee R2.00; Annual subscription R12.00 (town), R10.00(country). Letters of designation: A.M.S.INST.M.M. Affiliates shall be not less than twenty-five years of age, and shall have been engaged in positions of responsibility in, or associated with, the mining or metallurgical industries for periods of not less than three years. If, however, the candidate for admission to the higher grade of Affiliate, is at the time of his application, already a Student member, he need satisfy the Council only that he is, at the time of his application, engaged in a position of responsibility in or associated with the mining or metallurgical industries. In all cases the applicants shall satisfy the Council that they are fit and proper persons to become Affiliates. Entrance fee R2.00; Annual subscription R12.00 (town), R10.00(country). Graduate Members shall be not less than 21 years of age and shall be university graduates in pure or applied science, or have completed co-ordinated courses of study in pure or applied science of at least three years' duration at an approved university or institution. They shall not remain Graduate members after attaining the age of 30 years without the permission of Council. Entrance fee R1.00; Annual subscription R7.00 (town), R6.00 (country). Students shall be persons not less than 18 years of age who are being educated or trained in a manner approved by the Council, to occupy a technical position in or associated with the mining or metallurgical industries and who, furthermore, shall not have attained the qualification required for a higher grade of membership. They may remain Students until they have obtained the necessary qualifications for transfer to a higher grade of membership, but not after the end of the Institute's financial year in which they attain the age of 28 (twenty-eight) years. They shall then transfer to a higher grade to retain membership of the Institute. The Council may relax the provisions of this clause in such cases as it considers appropriate. Entrance fee nil; Annual subscription R3.00 (town), R3.00 (country). Other. The Council has the power to elect to the grade of Member or Associate Member candidates who may not fulfil all the requirements for entrance to these grades but whose status, professional achievements and practical experience in mining or metallurgy justify such election. Applications. Requests for membership application forms should be addressed to the Secretary: South African Institute of Mining and Metallurgy, P.D. Box 1183, Johannesburg.

The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. The objects of the Institute are to advance the science and practice of mining and metallurgy, to afford opportunities for the interchange and recording of knowledge of mining and metallurgy and to ensure high standards of professional conduct and competence. Membership benefits include monthly issues of the Journal of the Institute, monthly General Meetings at which papers are read, symposia, excursions to mining and industrial concerns and the use of club facilities at Kelvin House. Technical journals received on an exchange basis are available to members at the Johannesburg Public Library. The current membership of the Institute is over 1,400. Membership applications are accepted from suitably qualified persons and the requirements for entrance to the various grades of membership are summarised below. Members shall be not be less than 30 years of age, shall be university graduates in pure or applied science or shall produce evidence to the satisfaction of the Council that they have successfully completed a co-ordinated course of study in pure or applied science of at least three years' duration at an approved university or institution deemed by the Council to be of equivalent status. Members shall have been employed in senior technical positions in important mining or metallurgical undertakings for at least five years or they shall have practised as mining or metallurgical consultants for at least five years. They shall be practising their profession at the time of application. Entrance fee R4.00; Annual subscription R14.00 (town), R12.00 (country). Letters of designation: M.S.A.lNST.M.M. Associate Members shall be not less than 25 years of age and shall be university graduates in pure or applied science, or shall have successfully completed co-ordinated courses of study in pure or applied science of at least three years' duration. They shall have been engaged in work of an approved technical character in the mining or metallurgical industries, of which not less than two years shall have been in positions of responsibility. A candidate shall be practising his profession at the time of his application. Entrance fee R2.00; Annual subscription R12.00 (town), R10.00(country). Letters of designation: A.M.S.INST.M.M. Affiliates shall be not less than twenty-five years of age, and shall have been engaged in positions of responsibility in, or associated with, the mining or metallurgical industries for periods of not less than three years. If, however, the candidate for admission to the higher grade of Affiliate, is at the time of his application, already a Student member, he need satisfy the Council only that he is, at the time of his application, engaged in a position of responsibility in or associated with the mining or metallurgical industries. In all cases the applicants shall satisfy the Council that they are fit and proper persons to become Affiliates. Entrance fee R2.00; Annual subscription R12.00 (town), R10.00(country). Graduate Members shall be not less than 21 years of age and shall be university graduates in pure or applied science, or have completed co-ordinated courses of study in pure or applied science of at least three years' duration at an approved university or institution. They shall not remain Graduate members after attaining the age of 30 years without the persmission of Council. Entrance fee R1.00; Annual subscription R7.00 (town), R6.00 (country). Students shall be persons not less than 18 years of age who are being educated or trained in a manner approved by the Council, to occupy a technical position in or associated with the mining or metallurgical industries and who, furthermore, shall not have attained the qualification required for a higher grade of membership. They may remain Students until they have obtained the necessary qualifications for transfer to a higher grade of membership, but not after the end of the Institute's financial year in which the attain the age of 28 (twenty-eight) years. They shall then transfer to a higher grade to retain membership of the Institute. The Council may relax the provisions of this clause in such cases as it considers appropriate. Entrance fee nil; Annual subscription R3.00 (town), R3.00 (country). Other. The Council has the power to elect to the grade of Member or Associate Member candidates who may not fulfil all the requirements for entrance to these grades but whose status, professional achievements and practical experience in mining or metallurgy justify such election. Applications. Requests for membership application forms should be addressed to the Secretary: South African Institute of Mining and Metallurgy, P.O. Box 1183, Johannesburg.

By Dakota D. Faulkner

Cable bolts have been very effective in mine ground control. Non-tensioned and tensioned cable bolts are now used for both primary and supplemental bolting (Suder, 2001; Mirabile, 2010). In the United States, cable bolts are typically installed in either 1 or 1-3/8 in. (25 or 35 mm) diameter drill holes and, if point anchored only, are utilized with 4 - 5 equivalent feet (1.2 - 1.5 m) of resin. Cable bolts can be tensioned by various methods such as using an expansion shell mounted on the cable or post-tensioned with a hydraulic cable tensioning unit. In recent years there has been a desire to completely encapsulate the cable bolt for corrosion protection. Fully encapsulating a cable bolt with traditional resins can be very difficult. Keystone Mining Services, LLC (KMS) and Jennmar Corporation have developed a new cable bolt that can be fully encapsulated during installation or post-installation with polyurethane (PUR). The Fully-Grouted Cable Bolt (FGCB)* is equipped with a special head that allows the injection of PUR up through the cable bolt head and cable strands, completely encapsulating the cable and filling the drill hole. Although the FGCB was initially developed to fully encapsulate the cable for corrosion protection, it was also found that by modifying the cable bolt head and injection pressure, PUR could be injected into cracks and fissures of the strata to stabilize the roof. This paper details the development of this system and three underground applications under different ground conditions.

Jan 1, 2012