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The prime requirement is market, which for NZ inevitably means overseas markets. In order to be internationally competitive, the economies of scale and mechanical handling are essential. Since significant markets have not been sought, the full extent of our industrial mineral potential is not known. In general the technology exists to impart the desired quality, but at a price. Price is the main constraint, which may confine truly competitive operations to coastal situations to avoid high internal freight charges. Some commercial deposits of construction materials are being sterilised by zoning, making the costs to the consumer and country unnecessarily high. Unless management is enlightened and marketing is forceful, it can restrict growth. There is a good case to mount a search for phosphate minerals. The main growth areas are likely to be direct shipping ores like limestone, silica sand, and olivine, but in particular pumice.

Jan 1, 1978

By J. E. Matta

The methane gas emitted from coal samples collected from the conveyor belts dumping into silos was measured by the Bureau of Mines. Approximately 50 pct of the total gas desorbed into a sealed can within 1 week was released during the first 24 hours. No simple correlation between the gassiness of the coal stored and the methane concentration in the silo open space above the coal was found. This was probably because the gassier coals were stored in open-top Silos, which were better ventilated. Although the methane concentration in the open space above the coal pile was less than 1 pct for all 34 silos investigated, a methane measurement in the coal pile showed that high methane concentrations can exist. The methane released in the pile appears to accumulate and not liberate freely into the open space above the coal pile. Probably this gas is released during reclaiming operations, but further research is required to substantiate this claim.

Jan 1, 1978

By James McManus

The original analogue instrumentation at Lornex Mining Corporation to optimize the throughput by controlling the power drawn by the semi-autogenous mills was found to be inadequate because of the frequent changes in ore type. Although the trunnion bearing pressure of the mill was a crucial control criterion, it was not utilized in the original control scheme. After several plant tests of different types of analogue controllers were unsuccessful in finding any control equipment suitable for this application, it was concluded that a digital process control computer was required. Computer control strategy to optimize the grinding rate by controlling the power and the bearing pressure of the semi-autogenous mill was developed and a Fox 2 /30 computer made by Foxboro was selected. After six months of experimentation, it was found that the throughput was increased substantially by computer control.

Jan 1, 1978

By E. Allen Hendt

It is a pleasure to be invited to speak before a gathering of executives representing America's leading mineral companies, I welcome this opportunity, particularly because it comes at an important period in the development of U.S. commodity policy. This morning, I discussed our general commodity policy primarily in the. Context of the north-south dialogue between developed and developing countries. This afternoon, I would like to focus more specifically on potential cartel activity and U.S. mineral import dependence.

Jan 1, 1978

The clay slime generatea in many sand washing operations is usually very difficult to de-water. Treatment of these slimes is often limited by economic considerations and the properties of the solids to a gravity-driven process. The moisture characteristics of kaolinitic slimes from two different sand washing operations were measured.From these curves, equilibrium moisture contents for sedimentation and for drainage were calculated using the methods of soil physics. The validity of these calculations were confirmed by column experiments.The results show that the increased de-watering to be gained by drainage, as compared with sedimentation, is significant. Furthermore, observed rates of outflow indicate that water can be removed considerably morerapidly when drainage is possible.The practical application of these results to the dewatering of clay slimes is discussed.

Jan 1, 1978

Dewatering tailing slurries by mechanical means is often not possible and gravity and solar driven processes must be used. It has been shown previously that better use of gravity is achieved when the tailing is drained as it settles. Not only are more compact sediments obtained but also the dewatering is faster. From the results of laboratory and field tests reported here, equations were established which describe the evaporation and drainage components of the dewatering. These equations were used to calculate the effects of ponding depth, solids content of the tailing and clim- atic conditions on the time required to dewater the tailing. Since the calculations can be made with and without the drainage component, the advantages to be gained with drainage can be determined. The tailing used in the work was a clay slime from a sand washing operation. However, it is anticipated that this approach will be applicable to other similar tailing.

Jan 1, 1978

By Frank W. Bowdish

During the early 1960's, a method was developed for refining sand from the Arkansas River to produce a feldspathic product that was proposed for use in making colorless glass. Because of the need for chemical uniformity, a cooperating glass manufacturer specified certain ranges of percentages for each chemical constituent of the sand. These specifications were met by fulfilling the single requirement that alumina vary by no more than 20.1 percent from the specified value. This translated to a total variation of only about 1 percent in the feldspar content of the mixed quartz-feldspar products. Because the feldspar was lighter than the quartz, the average density of refined sand varied depending on composition. Densities, determined to five significant figures, of several samples were correlated with their chemical analyses, and the correlation could then be used with density determinations to more reliably indicate compositions than by chemical analyses only. The effects of several variables on the composition of refined sands were studied. There was a regular variation in the proportion of feldspar with screen size. A series of samples with their natural size distributions were more nearly uniform in composition than the same sands after screening and recombination. The screening and recombination process was done so that the sands had identical size distributions. Variations in the refining showed little effect on composition. A pile of flow-back sand from a construction sand washer was found to be severely segregated. However, samples taken from many points in the river near the sand plant and from the flow-back discharge pipe over several weeks very nearly met the uniformity specification. If care was taken to avoid segregation either before or during processing, it should be possible to meet the uniformity specifications for a feldspathic glass sand.

Jan 1, 1978

On the face of it this is an easily answered question. Modern technology and life as we know it today would be impossible without industrial minerals and the responsible utilisation of mineral resources is essential for the economic wellbeing of the nation. The quarrying industry supplies a high percentage of the industrial minerals used in New Zealand and our role therefore, is to ensure a constant supply of high quality roading and concrete aggregates so that society and the community as a whole can develop. We must do this in a manner which causes the least possible disruption to members of the community, which efficiently utilises all the valuable resources, which causes as little pollution as possible and last but by no means least, creates realistic profit for the operator. It is only by achieving a reasonable profit that we are able to continue in business and therefore play our part in the development of the country. Unfortunately, quarries have a poor image and are not generally popular, as on the whole, they are noisy, dirty and dusty and attract large trucks which create traffic problems. Judging by the amount of restrictive legislation with which we have to comply today, not even government or the local authorities want quarries which presents the industry with some serious problems, some of which will be outlined in this paper.

Jan 1, 1978

By H. J. Schroeder

Legislation and Government Programs.-The Occupational Safety and Health Administration (OSHA) accepted written comments until July 23, 1976, and held an informal hearing on August 24, 1976, to receive oral testimony regarding an economic and inflation impact statement prepared by OSHA on the proposed standard for occupational exposure to inorganic arsenic. These written and oral submissions were to be used in conjunction with information supplied at 1975 hearings to promulgate emission standards. An in-depth study for the Environmental Protection Agency (EPA) assembled and interpreted comprehensive information on arsenic and its compounds and the effects of these substances on people, animals, and plants.2 Another study for EPA assessed the role of arsenic and its compounds in the environment and in the economy of the United States and evaluated the need for and the projected effect of controlling its production, use, dissipation, and emission.3

Jan 1, 1978

By G. M. Ritcey

Sulphuric acid leaching has been up to the present, the most popular of the leaching routes. Oxide ores are usually leached with sulphuric acid directly by dump leaching, as practiced at the Bagdad or Bluebird Mines in Arizona, or by vat leaching as done at Inspiration Mining in Arizona. Upgrading of the low-grade oxide ores by dump leaching followed by cementation of the copper from solution by scrap iron has been replaced by the leaching-solvent extraction-electrowinning route which results in a high purity product at the mill site at reduced production costs compared to previous practice. High-grade oxide ores, vat leached with H2SO4, can contain, for example, 25 g Cu/l and 25 g H2S04/,l, or higher concentrations of both, and are presently fed directly to electrorefining plants. Advantages of coupling solvent extraction-electrowinning with the low cost dump leaching instead of using cementation, are as follows (1): a) the production of high purity electrolytic copper rather than cement copper;

Jan 1, 1978

By Ulrich Kappus

The purpose of the project is to divert flood flows of North Potato Creek. The project is located in the southeast corner of Tennessee near Copperhill, approximately 160 kilometers north of Atlanta, Georgia. The project consists of: a 28-meter high dam, a 90-centimeter diameter outlet conduit; an emergency spillway; and a 4.0-meter diameter hard rock trans-basin diversion tunnel. This floodwater management system was part of Cities Service Company mine safety program for the Cherokee orebody which is partially located within the stream channel. The following paper describes the entire project development from feasibility studies to design and construction management.

Jan 1, 1978

Since 1975 two electric hydraulic drills, a Robbins 11ND and an Atlas Copco C0P1038, have been part of the production drilling fleet at Mount Isa Mines Limited's Isa Mine. As might be expected with innovative and technically more complex machines, breakdowns and mainten- ance problems have been greater than those experienced with pneumatic drifters. This has been especially so with the COP1038 but in co-operation with Atlas Copco, many modific- ations have been made to alleviate operating problems. The training and quality of the maintenance workforce is of great importance. The use of coloured pictorial diagrams for hydraulic trouble-shooting will aid in minimising maintenance downtime. Both machines have achieved good operator acceptance. This is the result of many factors, the major ones being the more acceptable environmental conditions, the relatively low amount of physical effort and the high degree of mechanisation. The drilling area is one in which there is great potential for cost savings and product- ivity gains. Because both machines are capable of a high drilling output, Isa Mine is confident of achieving these aims.

Jan 1, 1978

By Donald I. Kurth

This Bureau of Mines report describes the development and application of a computer model of aquifer hydrology associated with in situ leaching of uranium. The model provides uranium resource developers with a simulation of leachant flow characteristics in a preproduction or pilot five-spot leaching operation. Various types of aquifers are modeled using closed form solutions of the partial differential equations describing the change in fluid head (pressure) as the leaching operation is carried out. User-supplied descriptive input consists of aquifer, well, and leachant flow characteristics. Numeric and graphic outputs such as isopressure, iso-velocity, and isotime contours are available. A typical application is shown.

Jan 1, 1978

By William C. Dixon

Since the mid 60's, several haul cycle simulation programs have been developed. However, most of these programs are believed to employ the continuous, rather than the discrete, event-oriented simulation approach to determine the haul cycle times. This paper describes the recently developed haul cycle simulation approach where time is advanced in varying amounts only as the system changes occur. This approach results in greater computational accuracy and increased computational efficiency. The program is written in FORTRAN and requires equipment performance curve and haul road profiles as input. Unique program capabilities include the handling of switchbacks and intersections. The program uses a master data file concept in which various haul road profiles found during the mine life can be simulated all in one job submission. The results of the model validation using the actual time study data provided by an open pit mine operator near Tucson, Arizona, are also described in this paper.

Jan 1, 1978

By Vernon O. Markworth

This report contains the results of tests performed on three large diesel engines to determine their ability to meet selected criteria of the Mining Enforcement and Safety Administration Regulations for equipment used in gassy, non-coal mines. Study efforts were first directed toward determining the types of equipment expected to be used in underground oil shale mines. Three typical engines in the 800-1200 horsepower range were then selected for testing. Intake flame arresters, exhaust scrubbers, and water jacketed exhaust system were designed and built for each engine. During testing, each engine was evaluated for its gaseous emissions output, adequacy of the exhaust gas cooling system, ability to withstand internal explosions, and adequacy of the flame arresters. Surface temperatures of the engine and exhaust cooling system were determined under full load operation.

Jan 1, 1978

By M. L. Joy

The heat pipe is a self-contained, passive structure that uses a liquid-vapour fluid cycle to provide high thermal conductance . Through the proper selection of working fluids and container materials, heat pipes have been operated at temperatures ranging from less than -300°F to more than 3,000 °F. The passive nature, high efficiency and configuration flexibility of the heat pipe are presented. The application of McDonnell Douglas Astronautics Company Cryo-Anchor® heat pipes for foundation and support stabilization in permafrost regions is discussed. Using the proven Cryo-Anchor technology base. a proposed application of heat pipes in a cold -region mine ventilation system heat recovery heat exchanger is presented. Information obtained from the development of an air-cooled heat pipe steam condenser provides the technical basis for large -scale heat pipe applications.

Jan 1, 1978

By R. P. Beyer

Low-temperature heat capacities and standard enthalpy of formation of copper difluoride (CuF2) were determined by the Bureau of Mines. The low-temperature heat capacities were determined from 11 to 302 K by adiabatic calorimetry. The enthalpy of formation was determined by HC1 solution calorimetry. The standard values of entropy (S°) and enthalpy of formation (?Hf°) at 298.15 K are l8.65±0.03 cal/deg mole and -129.02±0.29 kcal/mole, respectively.

Jan 1, 1978

To mine uraniferous sand-stone in an economically feasible and environmentally compatible manner without placing men underground. Approach Uraniferous sand is remotely extracted through a single borehole by cutting Into the are around the borehole with a high pressure water Jet, and pumping the resulting slurry to the surface. How It Works A 16-inch-diameter borehole Is drilled from the surface down into the burled mineral deposit, and the mining tool Is installed. High pressure water Is released as a jet from a nozzle In the mining tool to erode the are, forming a slurry that flows to the bottom of the cavity. The slurry Is drawn Into Inlets located near the bottom of the drill string. See drawing. After being pumped to the surface, the slurry is weighed, metered, and checked for radioactivity. It is then deposited Into one of a pair of sumps. Water collecting in the sumps drains Into an adjoining pond for reuse. Thickened are In the sumps is removed and placed In piles.

Jan 1, 1978

By C. J. Cajka

Commodity agreements, trade liberalization, producer cartels, the New International Economic Order, price stabilization and access to supply are buzz words of the day. The international concern and dialogue on these concepts, often by a new breed of politically motivated experts, have generated intense interest in seeking an international solution to natural resource problems. While this momentum was maintained during the past year, the growing incidence of protectionist actions by several major nations has been eroding confidence in the global approach. The seriousness of current difficulties has created an urgent need for decisive action. At the same time, the limitations of the global approach have become more evident.

Jan 1, 1978

Within the Ross River Basin, the following types of water were collected and analysed; 19 streams, 24 wells and bores together with 19 samples from the Ross River Dam. The waters were found to contain up to 269 ppm of silica and, although they meet the requirements for industry in all other respects, this extremely high figure means that two basic guidelines should be followed. All steam generation units, except those less than 150 psi should employ hot lime zeolite softening, demineralization or evaporation to remove silica. Cooling systems should only operate on a once through basis.

Jan 1, 1978