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Attempt has been made to determine the nature of charge on activated carbon surface by studying the electro-kinetic properties of the carbon in the presence of cations, anions and aurocyanide solutions. The zeta-potential measurements were made in the presence of individual ions and also in combinations. The cations and anions chosen were those commonly associated with gold bearing ores in Kalgoorlie area. It was found that the iso-electric point of Norit Carbon was at pH 4.45; below this pH the charge was positive, while above, it was negative. In the absence of gold cyanide solutions and in the presence of individual cations the i.e.p. shifted to the alkaline range (pH 7.2-8.5) while in the presence of anions the i.e.p. was shifted to less than pH 3.5. In the presence of aurocyanide solutions, the iso-electric point was still in the acid region irrespective of whether anions or cations were present. The probable mechanism for such a behaviour has been attempted after measuring the specific conductivities of solutions before and after gold adsorption, by studies using the electron- probe-mirco-analyser, and S.E.M. on the carbon surface.

Jan 1, 1982

By Pablo Velasco

The Belize economy recorded modest growth during 1980; the growth of the gross domestic product (GDP) in real terms was between 1% and 2%. At current prices, the 1980 GDP reached $108 million2. This output was largely attributed to the performance of a few industries, mostly nonminerals. Such performance improved significantly the balance of payments situation by reducing the deficit from $19 million in 1979 to $4 million in 1980. The rate of inflation was an estimated 18% in 1980 and would have been greater if not for a conservative monetary policy and price control on a number of essential items. Expert earnings increased $43 million, or 50%, from the 1979 level. After increasing more than 25% in 1979, imports increased only 6% in 1980 to a level of $141 million owing to the decline in investment and stabilization of petroleum prices. The balance of trade deficit was $9.8 million in 1980, a marked improvement from the 1979 level of $45.1 million. The mineral output for Belize accounted for only a fraction of 1% of the GDP. Such activity was limited to the production of limestone, marl, and sand and gravel, all of which were primarily used in construction of the Northern Highway between Orangewalk and Belize City. Mineral resources are deficient or nonexistent in Belize for the majority of metals and nonmetals, although the Government and others continue to believe that petroleum must exist in Belize. The proximity to Mexican oilfields and the growing finds in the Peters area of Guatemala support this expectation. The Government continues encouraging exploration onshore and offshore and offers terms that

Jan 1, 1982

By Scales PJ

Fatigue is the primary cause of failure of structural and mechanical components subject to dynamic loading. Recognition of this basic fact and the development of appropriate techniques and details are important in the design and repair of off highway trucks (OHTs). The frames and appendages of OHTs and other mobile plant used in the Pilbara are subject to tough operating conditions. Any fatigue-prone details quickly show up and become a maintenance liability of considerable concern. Much of this equipment is approaching the limit of its fatigue life and maintenance managers face decisions on whether to repair or replace. Even new equipment often contains some poor details which suffer distress soon after commissioning. In those cases a repair is required which will reinstate the detail to its original intended design life. Repair details must be practical and cost effective. They must also be tailored to the capability and expertise available in the field or in local manufacturers' establishments. This is particularly important where original equipment was manufactured overseas and long delivery times are involved. Lessons are drawn from components which have failed, using the evidence constructively, to provide an upgraded part or an improved substitute. With the experience now available it is relatively easy to extrapolate to cover new problem areas. This paper describes specialised techniques of mechanical fastening and detailing for low fatigue susceptibility, built up over many years of experience with OHTs and other mining plant and equipment in the Pilbara.

Jan 1, 1982

By Fernando Humberto Muge

One of the problems that arises in the early stages of the mine planning before the determination of the mining exploitation method is to predict what will be the recoverable ore reserves in tonnage, grade and metal quantity, if the select ion is based upon block grades. The estimation of these recuperation or recoverable functions can act as an important planning tool in what concerns the appraisal of the consequences of ore-waste discrimination of individual blocks in a selective mining operation. Estimation methods of all these functions are discussed together with cross validation tests using the available information concerning a preliminary drilling campaign accomplished during the exploration stage of an iron orebody located in the North of Portugal (Moncorvo Orebody).

Jan 1, 1982

By Martin T

High methane content of the medium volatile metallurgical coal mined from the Coal Basin mines causes very difficult mining conditions. Rapid desorption into the mine ventilation system limits coal production, requires huge fresh air quantities and creates mine safety problems. In workings deeper than 2000 ft (600m) gassy coal and heavy cover create outbursting conditions. Cross-measure methane drainage has reduced ventilation requirements on advancing faces, but degasifica- tion of virgin coal is needed to improve mining Conditions.

Jan 1, 1982

By George A. Morgan

The successful expansion of crude oil production begun in late 1977, led to promising development of the nonfuel minerals sector. Although actual production of nonfuel minerals was limited both in variety and in percentage of output on a world scale, the potential for expansion with a rapidly developing infrastructure was significant. The energy base was expanding with construction of two new hydroelectric powerplants in addition to the existing plant near Edea. The Song Loulou plant will have a 240-megawatt capacity, and a hydroelectric plant under construction in the northern part of the country by mainland China will have 72 megawatts of installed capacity. Inflation of between 15% and 20% resulted in a real gross domestic product (GDP) of $2.8 billion2 in fiscal year 1980 (July 31 to June 1), up 6% from that of the previous fiscal year. Petroleum became the leading export item in terms of value, surpassing coffee and cocoa exports. Mineral exports as a whole increased eightfold in value, mainly because of oil sales. Oil exports also caused a reduction in the trade deficit by nearly one-third, and the Government expected its 1980-81 budget to be balanced at $1.17 billion. The Port of Douala accounted for about 8 million tons of cargo, or 93% of total maritime traffic for Cameroon. Expansion plans for the port call for an initial increase to 5 million tons, and a cargo handling capacity of 7.5 million tons in 1985 and 10 million tons by 1990. The Port of Victoria will gain importance with the startup of an oil refinery. The country's third seaport at Kribi was used solely for timber shipments, and capacity at the Port was to triple by 1981. The Government operated its own shipping line with six oceangoing freighters. France was the dominant trading partner, accounting for 25%

Jan 1, 1982

By Whitmore R. L

The action of water on a number of Queensland shales which are associated with particular coal measures and oil shales has been studied. The results suggest that the disintegration of some of the shales could cause significant problems in mining and preparation operations. The extent of shale breakdown varies widely from deposit to deposit and from seam to seam but a suitable assessment procedure utilises the test described in AS 1661-1979, and an improved method of presenting the results is described in the paper.

Jan 1, 1982

This Bureau of Mines publication presents an overview of mine electrical power systems research currently being conducted by the Bureau. The papers, given at a Technology Transfer Seminar, emphasize the increasing importance of research related to the safety considerations of underground coal mine electrical systems. Selected topics are included that summarize results of research in the areas of electrical shock prevention, explosion-proof enclosures and load centers, discriminating circuit breakers, and trailing cables. Other topics discussed at the seminar are published as separate sections of the Bureau of Mines Hand- book "Application Notes--Mine Electrical Power Systems."

Jan 1, 1982

By James W. Hendrix

A survey of endomycorrhizal fungi occurring on orphan coalmine lands in Western and Eastern Kentucky revealed a great diversity of species present. Thus a large number of fungi are available for isolation and evalution for enhancing revegetation of mined land. Endomycorrhizal fungi isolated from orphan mines stimulated growth of sweetgum seedlings on mine soil at low fertilisation but inhibited growth at high fertilization; this growth inhibition at high fertilization did not occur with plants growing on peat-perlite. Banding of endomycorrbizal inoculum was not advantageous, compared with incorporation of inoculum throughout the growth medium, for production of mycorrhizal sweetgum seedlings. Newly reclaimed mine spoils were nearly nonmycorrhizal, compared with land reclaimed four or eight years earlier. A procedure for isolation of single-spore cultures of endomycorrhizal fungi was developed; this procedure is necessary for studies of ecotypic variability. A practical procedure using container-grown Pisolithus tinctorius-infected shortleaf pine seedlings for production of large numbers of bareroot pine seedlings infected with P. tinctorius for mined land reclamation was demonstrated.

Jan 1, 1982

By R. H. Sprute

This report describes a feasibility study to consolidate coal waste sludge in a 100-acre pond by applying direct current between floating and buried electrodes. The study was conducted by the Bureau of Mines under a cooperative agreement with Washington Irrigation and Development Co., located near Centralia, Wash. Part 1 covers results of laboratory tests at the Bureau's Spokane Research Center and a small-scale field test at the cooperator's coal preparation plant in western Washington. The process is efficient and cost-effective when power is applied at low current density. A proposed system, fully described in part 2, has electrodes covering 21 acres of pond surface radially arranged around a central power platform. Densification of pond contents would require 2 to 3 years of treatment. Total cost of equipment, labor, and material is approximately $500,000.

Jan 1, 1982

From the ventilation aspect, there is a basic difference between advancing and ezreating longwall layouts. Particular rroblems with retreating, using differing mining methods and layouts include high gas emissions, spontaneous combustion and -radients. There is an acceptable method of crntrolling the environment at the return end a retreating longwall face without the use a multiple heading system. Incorporated in the design is the facility to practice xtensive methane drainage, thus ensuring a ntrol of the rate of methane emission into the main roadways. Case studies highlight varying mining editions under which the proposed system of Ctised.

Jan 1, 1982

By Thomas L. Starks

Surface soil/spoil Samples (0-10 cm) from experimental test sites in western North Dakota were aseptically collected during August 1975 and each month (May through September) during 1076 and 1977. Selected samples were Cultured in a defined inorganic medium and after six weeks the algae were identified. Chlorophyll u content of the soil/spoil was used as a measure of the algal abundance. Soil physical-chemical properties, species variety and abundance were statistically analyzed. All test sites revealed distinct soil algal communities and demonstrated a successional trend as evidenced by significant increase, in species variety and bionmass over time. Some soil factors, calcium, copper, and phosphorus affected species variety and abundance at more than one situ. Others were important at specific sites; silicon and aluminum at the South Beulah test site; manganese sodium and zinc at the North Beulah test site No. 1 and boron, cadmium and magnesium at the North Beulah test site No. 2. Topsoiled areas had higher species varieties and abundances when compared with control areas, as did plots treated with amendments such as leonardite and fertilizer Generally.

Jan 1, 1982

By N. Malakondaiah

Several growth chamber and laboratory experiments were conducted to study the germination behavior of plant species on mine spoils and plant growth responses to nutrients on spoils and topsoils. Experiments were conducted to study the germination potential of some native and introduced species under various conditions. The seeds of green needlegrass, side oats grama, thickspike wheatgrass, crested wheatgrass, birdsfoot trefoil and emerald crownvetch were less tolerant, whereas those of alkali sacaton. durar hard fescue, slender wheatgrass, yellow sweetclover and alfalfa were most tolerant to the sodic mine spoil conditions. Addition of leonardite improved the germination potential of some of the poor genninators. Slender wheatgrass and yellow sweetclover were used as test plants to study the fertility status and productivity potential of stockpiled topsoils and spoils collected from Center. Glenharold and South Beulah of North Dakota. The topsoils were neither saline nor sodic but low in N and P. The spoils were neutral to alkaline with SAIL of 12-32, EC of 1.8-5.5 mmhos/cm, Olsen&apos;s P< µ4g/g, and total N <0.07%. Application of N and P together to the topsoils increased the yield of wheatgrass and sweetclover by 88% and 70% of their respective maximum yields, whereas near maximum yields were obtained for both the species by the same treatments to the spoils. The average yields on topsoils were higher than the yields on spoils. The concentrations of major nutrients were higher in plants grown on topsoil, whereas the opposite was true with the concentrations of Mn, Zn, and Cu. Growth chamber experiments were also conducted to study the growth responses of alfalfa, oats and slender wheat grass by the application of Mn and Zn to a sodic coal mine spoil which was previously used for pot culture experiments. Significant growth responses to Mn and Zn were observed in alfalfa but not in oats or slender wheatgrass. Fertilizing the spoil with Mn along with NPK increased the yield of alfalfa to 85% and with Mn + Zn to 99%. Growth responses and plant composition results of this study confirm that the application of major nutrients to spoils can accentuate Zn and Mn deficiencies in some plants.

Jan 1, 1982

By Steven W. Schmauch

A mineral survey by the U.S. Bureau of Mines and U.S. Geological Survey indicate the Blanco Mountain RARE II area has low potential. Lode deposits consist of small, mineralized quartz or quartz-gossan veins. The veins are sparse and widely separated and lead, silver and gold content is restricted in amount and concentration. No gold or other potentially economic minerals were found in a placer deposit. There is no evidence of industrial mineral, geothermal, or energy resource potential in the study area. INTRODUCTION A mineral resource survey of the Blanco Mountain RARE II area (No. 5059), Inyo and Mono Counties, California was conducted in July 1981. This report summarizes the results and interpretations of the Bureau of Mines investigation.

Jan 1, 1982

By L. R. Gremillion, G. H. McClellan

Chemical and mineralogical data on 25 apatitic phosphate ores of diverse origins from commerical deposits around the world were widely variable. From 14 to 18 chemical constituents of each sample were determined, and each sample contained four to ten mineral phases. Altogether there were 34 different mineral phases, many of which occurred in only one sample. Samples contained varieties of francolites, fluorapatites, and mixed hydroxyfluorapatites. The apatite compositions calculated from chemical data showed that certain types of substitutions were characteristic of different apatite varieties, but every variety had some degree of substitution of (CO3)2- for (PO4)3-, and the P205 contents of the apatites ranged from 35.1 %for a North Carolina apatite to 41.9% for a Missouri apatite. In a concentrate with a grade of 32% P2O5, the North Carolina sample should contain about 8.7% gangue and the Missouri sample about 23.7% gangue. To optimize the digestion process of a phosphate ore, it is necessary to consider the dissolution behaviors of different mineral phases during acidulation and their possible effects on chemical properties of a fertilizer intermediate. In the production of wet-process acids or superphosphates, acidulation of certain minerals may cause foaming and formation of sludge, filtration, corrosion, and handling problems.

Jan 1, 1982

By Ove Rehnberg

Catalytic purifiers are widely used as exhaust treatment devices on diesel equipment in confined spaces. The paper summarizes some studies carried out at the University of Lulea on diesel exhaust purifiers. The main purpose has been to elucidate important chemical activities of catalysts useful for the improvement of their effect. The effects of platinum catalysts on exhaust constituents such as carbon monoxide, nitrogen oxides, unburned gaseous hydrocarbons, and polynuclear aromatic hydrocarbons are discussed. Also pointed out are the great differences in catalyst activity and advantages/disadvantages associated with the catalysts.

Jan 1, 1982

By John D. Smith, Robert J. Mitchell

"There is a world-wide trend toward underground bulk mining methods employing hydraulically placed backfill. This trend is recent and therefore there is little in the literature to assist an operator in the design of backfill properties, the design of drainage facilities, the calculation of the operating forces on a bulkhead, and the control procedures considered necessary before, during and after pouring. This paper presents recommended procedures that are based on over to years of experience in the various aspects of backfilling large openings. Free-draining timber or concrete block bulkheads are shown to be a viable alternative to massive reinforced concrete bulkheads for the containment of backfill pours. Hydrostatic pressures cannot develop in backfills provided adquate drainage facilities are installed.IntroductionThe increasingly adverse relationship between mining costs and mineral values has led mining companies to develop more productive, lower-cost, bulk mining methods. This has led to the increasing use of large, more or less continuous, hydraulically placed backfill pours to enable the recovery of a higher proportion of pillar ore. The success of any bulk mining method depends on the degree of stability maintained during the stoping operations with reference to the mining rate, the performance of the backfill with respect to the per cent extraction of pillar ore, and the control of the mine structure with respect to safety and productivity. One such method has been previously described(I) where a steeply dipping orebody is being mined with a sub-level method that employs large, hydraulically placed tailings pours for delayed pillar recovery. The paper describes the rock mechanics analysis undertaken to establish the stope and pillar geometry and the approach taken to establish backfill strength requirements to prevent dilution during pillar recovery. Production with this method started in 1970 and because few, if any, large bulk pours had previously been used in- this way (judging by the lack of information in the literature), design data and criteria were needed for several aspects of the work. Methods to establish backfill quantities and pertinent ""in-place"" fill properties are described in 2, 3 and 4 in the list of references. Results of field measurements taken to establish fill pressures for bulkhead design purposes are described in 5 and 6. Laboratory large-scale model tests undertaken to confirm a fill strength design equation, which takes into account fill arching, have recently been completed. A paper describing these tests and the results will be forthcoming in the near future."

Jan 1, 1982

By MacLean L

In 1975 the Commonwealth Government established import parity pricing for all liquid hydrocarbons discovered after the 16th September, 1975. These discoveries were termed "new oil" to differentiate them from existing discoveries and production. Overnight the price of the product being sought trebled, resulting in greatly enhanced economics by increasing the potential returns on existing prospects and by making smaller plays economically viable. After 18 years of drilling, the offshore Gippsland Basin has attained a moderate level of exploration for a basin of its size. Fifty seven prospects have been drilled within the basin but only a few of these were drilled along the southern and northern margins, while the deep water areas along the eastern margin have remained virtually undrilled following the Hapuku-1 oil discovery. The major hydrocarbon accumulations within the basin are trapped beneath the Latrobe Unconformity surface and exploration has largely concentrated on this single play in areas immediately adjacent to the major producing fields.

Jan 1, 1982

By J. W. Howland

A demonstration of dozer blades, designed for recontouring area-mined spoil and shown effective at Kansas and East Texas surface mine sites, was conducted at a Northeast Arizona surface coal mine to determine their effectiveness in different climate and soil conditions. The specialized tools were: 48-ft angle blade (on side-by-side tractor), 24-ft grading bar, modified 24-ft "U" blade (on side-by-side tractor), and a 13-ft deep "U" blade. Interest in the increased dirt-handling capacity of a previously built 22-ft blade, resulted in the design of a new Centerflow Blade of good versatility, able to maintain increased flow in otherwise difficult-to-move spoil. The demonstration involved 263 acres and showed a reduction of 50% in reclamation costs and 20% in fuel requirements for this mine site over conventional equipment. This savings resulted from improved technology, trained operators, and rigorous application of supervisory and monitoring techniques. Procedures and results of the demonstration are presented and analyzed here, along with guidelines for application of findings.

Jan 1, 1982

By L. K. Marshall

The importance of high quality underground mine ventilation is readily apparent. The principles of primary and auxiliary mine ventilation, however, are sometimes less readily apparent. The first article in this two-part series discusses some general aspects of primary and auxiliary ventilation. Next month&apos;s article will detail considerations involved with auxiliary mine ventilation.

Jan 1, 1982