Search Documents

By William H. Breeding

The remarks that follow are based substan¬tially on experience covering 45 years, 80% of which have been in placer work, rather than on a review of available literature. Most commercial placers have been deposited by the action of water. The richer and more-difficult-to-mine placers are those in the headwater areas where gradients are steepest. The most lucrative placers are generally in intermediate areas where volumes are greater, fewer boulders are present, and gradients are from 3% to 1 ½ . The higher volume, lower grade placers are in the lower reaches of river systems where gradients are lower. Where gold-bearing rivers have discharged into the sea, wave action can concentrate values on beaches, past and present.

Jan 1, 1984

By D. S. Parasnis

The early beginnings of mining geophysics in Sweden can be traced back to the reign of queen Kristina in the 17th century. The mine compass, consisting of a freely suspended magnetic needle in a casing, was in use certainly by 1640 and probably earlier for locating iron ore deposits. Whether the mine compass was a Swedish invention or not is an unsettled question since the possibility cannot be overlooked that the celebrated Nürnberg compass-makers of the 16th century may have constructed it for the first time(1). Be that as it may, the mine compass was very extensively employed in Sweden for more than two centuries and met with spectacular success in locating magnetic deposits under shallow overburden. Occasionally the diligent prospector would even be rewarded with a pyrrhotitebearing sulphide deposit, as witness many old sulphide-ore pits and some mines still in operation from the 17th and the 18th centuries. The mine compass measured only the orientation of the Earth's magnetic field and not its strength. Although it was improved in construction and sensitivity over the ages, no great strides were made in magnetic prospecting after the initial discovery of the use of the compass until Gauss, omnipresent in 19th century physics and mathematics, showed with the assistance of Weber how the strength of a magnetic field could be determined.

Jan 1, 1975

By W. C. Morgan

This paper discusses some of the problems involved in predicting the productivity of a shovel and truck fleet in a new set of operating conditions. More specifically, it concentrates on the problems of predicting the travel times on the haul and return portions of the truck cycle under new profile conditions and the prediction of the interaction effect between the shovel and trucks at the loading point. The ability to calculate the travel times for a new road profile is not new. Additional corrections of these calculated times for expected actual operation can be made. In considering the interaction between the loader and the hauler, there are two approaches that can be taken. Probably the most accurate method of predicting the shovel-truck interaction is a simulation of the step-by-step operation considering the variation in cycle times of the shovel and trucks. This is usually called a stochastic simulation and requires input describing how these cycle times vary. However, by understanding the causes of this shovel-truck interaction it is possible to make sufficiently accurate predictions with much simpler methods. For the purpose of this discussion let us assume that the problem involves trying to predict the productivity of a single shovel-truck fleet at some future time in an existing operation. Let us also assume for simplification that the new operation to be simulated has the same loading and pit conditions and the same dumping conditions as did the existing operation. Therefore, the only difference would be the difference in the hauling profile for the new operation. The problem then becomes one of predicting the change in the travel times on the haul and return portions of the cycle, and in determining the change in interaction between the shovel and trucks with the new truck cycle times.

Jan 1, 1968

By Wallace Macgregor

The direct investment role of Middle Eastern oil producing countries in future world-wide mineral development probably will be a limited one for the next five years. Their needs and their longer range economic objectives substantially preclude any such risk taking ventures. There is, of course, the possibility of political in- vestment. One hears many rumors and doomsday calculations of what the Arabs might do with the rising accumulation of surplus funds. Up to now, this kind of investment has been more in rhetoric than in money. For the most part, oil producing countries of the Middle East have been, and will be, investing surplus funds with strong emphasis on the preservation of capital. They will seek security first and yield second just like any other prudent investor. In several respects, this is regrettable. A direct infusion of risk capital into mineral development, especially in the Third World countries, is a constructive way of enhancing their earning power which many desperately need just to stave off starvation. It would also be a good way of eliminating material shortages in the industrialized world. Most important of all, it would help to ultimately reduce inflation without imposing the hardship of recession. So why isn't it done?

Jan 1, 1975

By R. M. Jacobs

Can your company afford to issue a check today for $100,000, $500,000, $2,000,000, or $22,000,000? This is what it might cost your company if it is on the losing end of a product liability suit. During the past 10 to 15 years, the number of product liability actions has grown from a handful per year level to a hundreds of thousands per year level. Settlements and awards in the tens and hundreds of thousands of dollars are not unusual in these days. The largest award that the authors haw heard about is a case involving a private airplane and the death of four men, which was awarded over $22,000,000. In the materials handling field, a fork lift truck, ordered with an overhead guard, was delivered without a guard because one was not available at the time. An accident with serious personal injury followed. Wouldn't it have been better to have waited until the guard was available before delivering the unit? Answer: a quarter of a million dollars better -- the cost of the settlement. Hoisting devices are also not without their liability precedents. In a 1960 case, an employee was injured when a load abruptly fell from a hoist. It was determined that the operator could not possibly have caused such a fall had the hoist been functioning properly. The case was compounded when the manufacturer of the hoist contended that the load had been improperly connected to the device, since the same hoist was used to remove the weight from the injured man without another malfunction.

Jan 1, 1973

By R. A. Matuszak

In recent years, a new concept in the control of electrically powered excavators has come into existence. The new type of control system has come to be known as "static" control. The use of the name "static" to describe this system is somewhat misleading since this term refers only to one of the many advantages of this very important advance in excavator control systems. In 1959, the first truly "static" control for Ward-Leonard equipped electric excavators was designed, developed and placed in service. The control system, originally intended only as a more modern electronic type of alternate to the tried and proven rotating amplifier control system then in use, has since proven to be much more.

Jan 1, 1964

By Richard G. Almes

Since the failure of a major coal refuse disposal embankment and impoundment in the Buffalo Creek watershed near Man, West Virginia in early 1972, there have been extensive changes in the design and construction requirements for coal refuse disposal facilities located throughout the United States. The primary emphasis has been on improving the safety of these facilities, particularly for impoundments which are capable of storing millions of gallons of process water and storm runoff. The Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor (formerly the Mining Enforcement and Safety Administration, U.S. Department of interior) has been the lead federal agency in promulgating regulations pertaining to coal waste disposal. In 1974 and 1975, studies were undertaken by our firm under contract to the Mining Enforcement and Safety Administration to prepare a comprehensive engineering and design manual to be used by operators and engineers in the planning and design of coal refuse disposal facilities with the intent ion of avoiding any more Buffalo Creek failures. The resultant 800-page document addresses major subjects such as safety, environmental controls, and cost. Specific topics include characterization of coal refuse, classification of disposal facilities, project planning, geotechnical investigations, testing and design requirements, hydraulic and hydrologic design, environmental factors, operations, and monitoring, instrumentation, and maintenance.

Jan 1, 1980

By Ray E. Harris

A resource of 134,400,000,000 tons of minable trona and mixed trona and halite underlies an area of about 1,300 square miles vest of Green River, Wyoming (Culbertson, in preparation)(Figure 1). In 1982, the total domestic consumption of soda ash (refined trona) was 6,667,000 short tons (Kostick, 1983), approximately 90 percent of which came from Wyoming trona. This enormous resource occurs in the Wilkins Peak Member of the Creen River Formation (Eocene). The Green River Formation is derived from sediments deposited in a large lake (Lake Gosiute) that occupied the Green River Basin in south-western Wyoming 38-54 million years ago. The Wilkins Peak Member represents a restricted, evaporite-rich cycle of deposition during which time the trona deposits were formed. A total of 42 trona beds are known, of which 25 are of sufficient thickness and extent to be considered minable (Culbertson, in preparation).

Jan 1, 1984

By J. E. Litz

The hydrometallurgy review did not arrive in time for publication in the May issue. 1992 was not a banner year for hydrometallurgical installations or new hydrometallurgical developments. Installation of copper solvent extraction/electrowinning circuits were under construction or began operation in Nevada (Yerrington ), Arizona (SilverBell), Chile (Copiapo and Escondida), Peru (Toquepala and Cuayone) and Australia (Girilambone). These installations will produce more than 100 kt/a (110,000 stpy) of cathode copper. Several new heap leach gold facilities using conventional technologies were announced or were put into operation. New technologies undergoing widespread testing include biological oxidation of low-grade ores in a heap leach mode and evaluation of new agglomerating agents.

Jan 1, 1993

By G. L. Alston

The mine disaster last November in northern West Virginia has compelled the coal mining industry to take a closer look at the methods of transporting and applying rockdust. The USBM has indicated they would like to see a minimum of 80% incombustble in the back entries and want rockdust to be maintained to within 40 feet of the face at all times. With today's high rate of advance of mining machines it will be necessary to apply dust in the immediate returns continuously and the working places mutt have dust applied during the operating shift. The inspectors have become more demanding in requiring clean-up of coal and coal dust in the working place before rockdust is applied and are insisting on better clean-up and better rockdust applications along belt conveyors. Maintaining a constant application of rockdust in the back entries can be done with a Trickle-Duster. The machine is designed with hopper capacities of either 400 or 1,000 pounds of dust. The discharge rate of dust being fed through 1-1/2 inch diameter hose can be adjusted from 1/2 to 5 pounds per minute. The hose is extended into the return through the last open breakthrough and the return air carries the rockdust along w th the coal dust, depositing them uniformly on rib, roof and bottom.

Jan 1, 1969

"In this review, the sintering process is first described and analyzed to identify the key factors affecting the structure and quality of iron ore sinter. Under fixed sintering conditions, the granulation efficiency, nucleus stability and primary sinter melt volume and properties of the iron ore are considered to have significant influence on the sinter structure and quality. Discussion is then focused on the effects of the chemical, physical and mineralogical characteristics of the iron ore on these key factors, and the consequences for sinter quality.IntroductionSintering is the most economic and widely used agglomeration process to prepare iron ore fines for blastfurnace use. In modern blast furnaces, particularly in East Asia, iron ore sinter typically constitutes more than 70% of blast-furnace ferrous feed. High sinter quality and efficient sinter production are thus required both to withstand extreme operating conditions and maintain the productivity of modern blast furnaces. At the same time, due to the increasing depletion of high-grade iron ore resources from large deposits, iron ore producers are moving toward developing an increasing number of deposits of much smaller sizes to maintain current production levels. It is therefore imperative for iron ore producers to develop long-term strategies to maintain the quality and consistency of the iron ore fines they are producing while exploiting these smaller, complex deposits. The iron grade, gangue minerals present, overall mineralogy as well as physical characteristics of iron ore fines being mined from these different deposits vary considerably. Overall, ores now have highly complex mineralogy, are becoming more porous and friable, and contain increasing amounts of gangue minerals, which will have important implications for the sintering process and sinter quality.Blending is one of the most effective options being explored by iron ore producers to deal with multiple small complex deposits. This allows the iron ore producers to reduce the number of products and take full advantage of the unique characteristics of each individual deposit to achieve long-term product consistency while increasing production. Blending is also a common practice in sinter plants as it is almost impossible to produce from one single ore a high-performance sinter mixture with the required processing characteristics. A typical sinter mixture used in Japanese steel mills (Nakano and Okazaki, 2007; Matsumura et al., 2013) often contains five or more ores to achieve balanced sinter quality and productivity with relatively low cost of raw materials."

Jan 1, 2015

By J. G. Asbury

Broadly conceived, the demand for electricity depends upon three sets of variables: (i) the growths of the many individual demands for energy services; (ii) the competitiveness of electrically driven technologies in meeting these demands; and (iii) the energy-conversion efficiencies of installed electrical technologies. The first set of variables establishes the size of the potential market; the second, the market penetration of electrical equipment; and the third, the quantity of electricity required to operate the equipment. All forecasts of electricity consumption ultimately depend upon inferred or assumed relationships to describe the future behavior of these variables. This partitioning of the demand-forecasting problem is conceptually useful and will guide the discussion presented in this paper. However, it is also something of an oversimplification. Examined in more detail, the electricity fore-casting problem is exceedingly complex. The variables mentioned above are, in turn, found to depend upon more fundamental sets of demographic technological, resource, and policy variables. The demand projections developed by the major forecasting services are usually developed in terms of these underlying variables, which themselves must be independently forecast.

Jan 1, 1985

By James R. Strong

Before getting into the subject of packaging and materials management, please permit me to introduce you to MICRO SWITCH. MICRO SWITCH, A Division of Honeywell Inc. is located in Freeport, Illinois. We manufacture and market thousands of types of precision snap-action electrical switches. Most of them are used as components by other manufacturers in industrial and commercial products. MICRO SWITCH also offers a broad line of industrial control devices including heavy- duty limit switches, relays, manual controls and proximity switches. Other product lines are solid state keyboards for the computer industry and high-performance d.c. motors used in computer related equipment. So you can see that we are a component manufacturer. With the exception of the keyboards, every one of our products would "fit comfortably into a breadbox." Some are so tiny that one could easily fit several thousand into a man's hat. In my position as supervisor-packaging. package design, and materials handling engineering, I am actively involved in package design projects, parts handling design projects, and numerous activities involving departmental layouts, storage facilities, and material handling equipment. Two package design technicians, a materials handling engineer, and a materials handling technician make up the technical staff.

Jan 1, 1973

By James E. Lonergan

To determine the best materials handling system for surface mined materials, one must develop a mine plan for each candidate system based on the most efficient use of that system. This is essential for a fair, unbiased economic compari¬son of the candidate systems. This paper will present two case studies where an integrated mine planning /systems engineering approach has been utilized at different levels of detail in the analysis of an in-pit crushing/conveying system vs. total truck haulage at 2 open-pit copper mines.

Jan 1, 1985

By J. B. Knaebel

I have been asked to discuss the "Development of the Twin Buttes Mine for Production." This property, which is a large low-grade open pit copper mine about 25 miles south of Tucson, Arizona, was recently brought into production by The Anaconda Company under a long-term lease agreement with the Banner Mining Company. Since the scope of this paper is limited to the subject broadly indicated by its title I will confine discussion of historical, environmental and other general matters to a brief summary sufficient, I hope, to establish a background of those conditions which influenced our approach to the technical and economic problems that faced us at Twin Buttes. The paper deals primarily with our studies and activities related to the solution of these problems and with the resulting engineering and business decisions that were taken - decisions which culminated last September in the initial commercial operation of another major open pit copper producer unique and interesting in several respects.

Jan 1, 1970

By Donald V. Fites

The evolution of open-pit mining has been rapid during the last two decades. The development of larger, more productive and efficient equipment has been one of the key factors in this open-pit advancement. Selection of the proper equipment and its correct usage is paramount to successful operation while maximizing return on investment. The quantity of material being moved prior to mining the saleable product is increasing at a significant rate. For example, at a southwestern copper mine more than two hundred million tons of over- burden have been removed prior to exposing an ore which contains less than 1% copper. A recent survey of twenty-three Western Hemisphere copper mines reveals the average strippingratio was 2.2:l with a range of 0.9-8.5:l. In the face of increased mineral demand, the resulting technological developments and rising overburden to ore ratios, many open-pit mines now use totally different concepts for the removal of ore and overburden. An increasing number of these concepts now being installed include wheel tractor scrapers as a major part of the material handling system for unconsolidated overburden removal. To say scrapers move only unconsolidated overburden is incorrect. On the contrary, ripped phosphate rock, copper ore, iron ore, and moderately consolidated overburden are also being moved by scrapers in various areas of the world. As reported in the Minerals Year- book, however, about one-half of the material moved in metal and non-metal mines is never drilled and blasted or broken by other means. We will, therefore, in this paper, concentrate on the role of wheel tractor scrapers in unconsolidated overburden; the area of greatest usage.

Jan 1, 1969

By James M. Stauffer

There are many types of filters designed to separate a solid from a liquid, including plate and frame presses, pressure leaf filters, gravity filters and vacuum filters. This discussion will be limited to continuous vacuum filtration and, specifically, to continuous rotary vacuum disc filters, drum filters and horizontal belt filters. The use of vacuum filtration can be advantageous in that: 1. The feed slurry can be delivered to the filter either by gravity or by a simple, inexpensive low pressure pump that only has to overcome the resistance of the feed piping system. 2. The filter equipment does not have to withstand high pressures. Consequently, a wide range of materials of construction, including plastic and fiberglas reinforced polyester (FRP), can be used in the fabrication. 3. After the form time, the filter cake is exposed to the atmosphere and the cake is accessible for further operations such as mechanical or physical dewatering, washing, and sampling on a continuous basis. 4. The discharge of the dewatered solids is continuous for directly feeding to the next operation; for example, a dryer. 5. Various methods of discharge can be fitted to the filter to effect optimum discharge of the dewatered cake solids. The principal of operation of a vacuum filter, regardless of type, is basically the same. The filter incorporates a filter medium supported on a drainage system and arranged so that the mixture to be separated (feed slurry) can be introduced to one side of the filter medium on which the solids are trapped and through which the liquid (filtrate) flows due to the applied vacuum.

Jan 1, 1979

By Z. R. Llanos

The petroleum refining industry makes extensive use of catalysts for the conversion of crude oils into more usable products such as gasoline, fuel oil and gas, aromatics, and others. Catalysts used for hydraprocessing contain cobalt-molybdenum or nickel -molybdenum, although there are catalysts that also contain tungsten. During hydroprocessing, nickel and vanadium are deposited on the catalysts, eventually rendering them inactive. The refiners are then confronted with the problem of disposing the spent catalysts. In the past, landfilling was a common method of disposal and it is still practiced in some countries. Other refiners prefer to stockpile the spent catalysts at the refineries until the price of metals warrants their sale to metal reclaimers. This practice, however, poses environmental problems to the refineries for storage and disposal of spent catalysts. Other types of catalysts are amenable to regeneration. The purpose of this paper is to focus attention on the recovery of nickel, cobalt, molybdenum, vanadium, and alumina from spent hydroprocessing catalysts by Gulf Chemical and Metallurgical Corporation and to review the use of sodium hydroxide and sodium carbonate for pressure leaching of spent catalysts.

Jan 1, 1986

By Aixiang Wu, Minjie Zhang, Zhuen Ruan, Yiming Wang

 The paper combines theoretical and experimental analysis to improve the accuracy of predicting paste yield stress by slump flow. It derives an analytical model of slump flow for yield stress, providing a theoretical basis for quantifying the rheological properties of paste with slump flow. The study uses three different tailings-prepared pastes and constructs an empirical yield stress model, showing high accuracy and good generality.

Aug 1, 2023

By Neil E. Izatt, M. Andre de Ruijter, Ronald L. Bruening, Wesley Young

IBC Advanced Technologies, Inc. has developed ligands, ?amed SuperLig®, which have specific applications in the gold mdustry. These ligands use molecular recognition technology (MRT). One ligand has been developed to selectively recover gold and silver from tailings solutions and from pregnant Merrill-Crowe solutions. Another ligand removes free cyanide, _ th10cyanate, other cyanide species, as well as copper and other base metal cyanide complexes from leached gold-ore solutions. The development of these "species selective'' SuperLig® prod­ucts allows for the more efficient operation of gold recovery processes and opens up the possibility of the economic devel­opment of high-copper gold ores. The resulting gold eluate is a high grade and a high purity stream which will simplify the need for further refming. Engineered systems based on MRT consist of a few unit operations utilizing standard equipment and mate­rials of construction. The process is simple to operate, thereby lending itself to automated modular design, which is both eco­nomic to manufacture and to operate. Test results for the gold and cyanide-copper systems are presented in order to demonstrate the high selectivity and effi­ciency of MRT technology in recovering these species from solution. . IBC Advanced Technologies, Inc. (IBC) and Fluor Daniel, Inc. formed a strategic alliance in late 1994. The goal of the alliance is to combine IBC's scientific expertise in the MRT field with Fluor Daniel's engineering capabilities in the metal­lurgical industry. IBC has its headquarters in American Fork, Utah, USA, where research, development and manufacturing are conducted. Fluor Daniel is an international engineering and construction firm with head offices in Irvine, California, USA. Engineering efforts for the alliance are centered in the Fluor Daniel Mining and Metals Operating Company office in Vancouver, B.C., Canada.

Jan 1, 1996