Search Documents

Compagnie Minière Espérance mines a primary gold orebody in an openpit. The ore is processed through crushing, primary gravity concentration, grinding and secondary gravity separation, generating tailings with remaining fine gold. Analysis of the material in the pond has indicated a residual gold grade sufficient to justify a chemical treatment process to recover the gold. However, direct cyanidation would require a prohibitively large installation for the site, which is located in a remote rainforest environment. It was decided to test the feasibility of preconcentration using flotation. As lab tests proved up the technical feasibility of the flotation process, an on-site pilot operation was carried out to assess the continuous circuit performances, define the best configuration and obtain enough data for industrial circuit sizing. Data collected during the pilot campaign was used for calibrating a process simulator built with the USIM? PAC software. The simulator validated the feasibility of upgrading the existing plant, including the reprocessing of tailings to obtain an acceptable fine gold recovery from a small amount of concentrate.

Jan 1, 2010

By Dennis S. Kostick

Soda ash is produced in over 39 countries by the Solvay ammonia-soda process or by mining natural sodium carbonate deposits. The total production of soda ash in 1980 is estimated at slightly over 29 million metric tons. Synthetic production accounted for over 75% of this amount with the balance of production originating from natural sources (either trona or sodium carbonate-rich brines) found primarily in the United States, Mexico, Kenya, and Chad.

Jan 1, 1981

By A. J. Basu

Computer assisted mine planning and design applications are routinely used by many Australian mining companies, However, the design process requires human expertise to recognize and evaluate the potential pitfalls. This paper introduces the application of a commercial optimization software (WHITTLE 4D) for strategic planning of an open pit mine in Western Australia. The authors present their experience in intelligent application of the optimization program while incorporating many technical and nontechnical obstacles. This paper provides some guidelines on how to apply the optimization software without loosing sight of practicalities. Moreover, this paper also shows how to build project evaluation guidelines for non-experts.

Jan 1, 1997

By Wi11iam I. Rau

In the recent past, there have been numerous projections of the capital requirements for additional mine and processing capacities required to meet projected non-Communist World demand for minerals during the next 15 years. A consensus judgment would place this currently at $14 billion per year, with the largest expenditures required for increases in aluminum and copper production. Until the early 1960's, internally-generated funds were used to finance nearly all of the large mining companies' capital requirements. Since that time, however, the enormous rise in capital costs per ton of capacity, accompanied by a relative stagnation in the financial condition of many of the major mining companies, have caused the industry to begin to rely on external sources for financing expansion, most notably, project financing from commercial banks and institutional lenders. Seven years ago, it was estimated that, in the five-year period 1972-1976,75% of the total capital requirements of $10 billion per year would come from internally-generated funds, with the balance to be provided by external sources. l There is little doubt that, in the coming decade, the percentage provided by external sources will increase. There should be little difficulty in attracting the necessary investment within the U.S., particularly in view of the expected continuation of companies in diverse industries seeking mineral investment opportunities. The more serious question lies in the availability of internal and external sources of funds for the expansion of mine and smelting capacity in the developing countries. Recently, R. F. Mikesell projected an average annual investment of $4.7 billion (in 1977 prices) over the 1977-1990 period would be required from foreign sources to expand metal producing capacity in developing countries. Mikesell concluded that external financing of mining projects in the developing world has averaged less than $1 billion per year over the past five years, thereby requiring more than a quadru1ling of this financing over the next decade.

Jan 1, 1978

By James K. Kindig

Solvent extraction as a method of purifying and concentrating metal values from solution has become a standard hydrometallurgical operation for recovery of both uranium and vanadium, and within the past two years it has been put into operation in a commercial plant for recovery of copper from leach solutions. In this first full scale solvent extraction plant for recovery of copper operated by Ranchers Exploration and Development Corporation near Miami, Arizona, a kerosene solution of an organic compound, LIX-64® is used to selectively extract the copper from the dilute acidic copper sulfate leach liquor obtained from heap leach operations. The copper is back extracted from the solvent into a stripping solution which is fed to an electrolysis circuit producing cathode copper for sale.

Jan 1, 1970

By H. W. Judges

A 16.5-kt/day underground molybdenum mine is being developed at Questa in Northern New Mexico by Molycorp, Inc., a wholly-owned subsidiary of Union Oil Company of California. Construction of the underground mine began in 1979, and first production is scheduled for early 1983. A gravity block caving method has been selected for mining the ore. Access to the mine will be through a service shaft, development shaft, and a conveyor decline. The shafts are being sunk under contract and the conveyor decline is being driven by Molycorp. The driving of the decline began in February, 1979 with a 10-man mining class. By the first of May, enough men had been trained to begin a continuous operation and by March 1, 1980 the face had reached the 1500 m mark. The heading is being driven with trackless rubber-tired equipment using a three-boom drill jumbo, 2.7 m3 LHD units and 7.3 m3 trucks. Ground support has been by rock bolts and wire mesh, followed by Fibercrete. A 16.5-kt/d underground molybdenum mine is being developed at Questa in northern New Mexico by Molycorp, Inc., a wholly-owned subsidiary of Union Oil Company of California. The new $200-million underground project will revitalize mining and milling activity at Questa, where small scale underground mining first began in 1920. Large scale open-pit mining was initiated in 1965 but now, because of the high stripping ratio, surface mining is being phased out. Construction of the underground mine began in 1979, and first production is scheduled for early 1983. The company expects full capacity - 9 Gg of molybdenum per year - to be reached in 1984.

Jan 1, 1980

By R. Zins

During the past few years, a completely new concept has been applied to the design of drives for operating at very low speeds. In this, the motor is supplied by a variable-frequency thyristor cyclo-converter. Today, frequency converters with practically unlimited power ratings can be constructed. The system frequency of 50 or 60 Hz is reduced to about 10 % of these values. This makes it possible to operate the synchronous motor, which has a correspondingly high number of poles, at the extremely low speed of the driven mill, i.e, without interposed gearing. The first motors of this type were built to drive ball mills in the cement industry, which are very similar to those employed for ore processing. Here, too, the tendency is to build units of ever increasing capacity. In the case of conventional drives with mechanical gearing, this involves correspondingly increasing difficulties. These difficulties have prompted various studies of the possibility of applying the new type of drive to ore mills as well, but a gearless drive has not yet been built for this application. However, gearless drives for ore mills will certainly materialize soon and it was therefore considered a logical step to report at the A.I.M.E. Conference on the experience gained with these drives in the cement industry, and on the present state of development.

Jan 1, 1973

By B. S. Graves

Deep well disposal of selected industrial wastes has been proved feasible and acceptable in the New Orleans area by several industries including Shell Oil Company's Norco Refinery and Chemical Plant where three of the six successful disposal wells in this area are operating. Well design and procedures for restoration of capacity are based, in most cases, on the principles of brine injection developed by oil producers in South Louisiana. Geological formations in the Gulf Coast area are suited to this type of injection because receiving strata are porous, isolated from sources of potable water and their water is compatible with the liquid wastes to be injected. This method of disposal is a simple, complete and economical solution to the problems presented by certain hard to treat wastes.

Jan 1, 1964

By Stanislatv Pawlowski

New, large sulphur deposits were discovered in Poland in 1953, the result of investigations by the National Geological Institute. All deposits occur in a widespread Miocene evaporite unit in the Carpathian foredeep. The gypsum underlying impermeable Sarmatian clays was altered to limestone and native sulphur where penetrated by hydrocarbons and bacteria. All deposits occur in Miocene structural uplifts. The early determination of the genesis of the sulphur deposits and their occurrence in elevated blocks led to an exploration program that successfully located new deposits.

Jan 1, 1978

By R. D. Coursen

Tin has been one of the very few commodities which has been covered by an international commodity agreement. It is the only metal so covered. The reason behind tin's prediliction for an agreement has been the inconsistency of the price pattern for tin during the entire 20th century. It is not surprising in view - of the wide and wild fluctuations in its price that tin has been called the Cinderella metal. An examination, for example, of prices in 1977 alone attests to the erratic behavior of the tin markets. The high was recorded on October 27 at M$1,895 per picul and the low on January 3 at M$l,314 3/8, on the Penang market, a spread in Malaysian dollars of $581 for a picul weighing 133 1/3 pounds. The first steps in international cooperation on tin were taken after the price bonanza of the First World War. Despite a lack of increased consumption, and in spite of the fact there was no shortage of mining production during the war, prices boomed. Shipping shortages and thinning stocks brought about a situation where in the U.S., industrial stocks were only 1/6 of what they had been in 1914. The boom busted early. In 1921 the tinplate industry of the world had cut its output in half and total world consumption of tin fell by 1/3. Tin producers became so concerned that they created what was called the Bandoeng Pool. It accumulated stocks held by countries now known as Indonesia and Malaysia, amounting to 28 percent of the combined production of the two countries and about 15 percent of the total world for 1921. The pool holdings were shortly exhausted and thereafter in the years 1924 to 1928, general boom conditions existed for tin.

Jan 1, 1978

By V. Rajaram

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) imposed a no-blasting specification (blasting is restricted to the construction shaft and shaft bottom or boot) on the Deep Tunnel project in 1988. This was prompted by numerous complaints from the residents in the vicinity of the project, and controversies experienced on previous projects from blasting the rock overlying the tunnel. This paper will describe the methods utilized by two major contractors who are driving 20 km (12.5 of tunnel along with drilling over 36 shafts under this restrictive specification. The impacts on design, construction, schedule, cost, and the environment are detailed.

Jan 1, 1991

By Jeff LeBlanc, George Gutierrez, Carl Pitzer

The Bay Park Conveyance Project was one of the largest microtunneling and rehab projects in the United States at the time of completion. The completed project conveys treated water from the South Shore Water Reclamation Facility located in Nassau County, New York, which currently discharges an average of 50 million gallons per day (MGD) of treated water into Reynolds Channel, to the Cedar Creek Water Pollution Control Plant (WPCP) ocean outfall pipe. The pipe carrying treated wastewater was installed approximately 20–60 feet below the surface. The treated wastewater is conveyed via microtunnel construction of a 2-mile long force main from the South Shore Water Reclamation Facility to an existing aqueduct under the Sunrise Highway, the rehabilitation of an 7.3-mile stretch of the aqueduct via sliplining, and construction via microtunnel of a 1.6-mile-long force main to connect the rehabilitated aqueduct to the existing Cedar Creek Water Pollution Control Plant (WPCP) outfall, which discharges and diffuses treated water three miles offshore in the Atlantic Ocean. This paper will review the Design-Build requirements, the chosen innovative solutions during planning for the micro tunneling portion of the project and review the microtunnel construction on the project.

Jun 23, 2024

By E. Tarshizi

This research project demonstrates the application of a mine system simulation and animation model in enhancing the efficiency of a truck-shovel operation and reducing the haulage environmental impact in an open-cut coal mine. In any mine, a key objective is to have enough equipment for production and not have excess to where it is counterproductive. Due to the advent of responsible mining, environmental regulations, and eco-friendly practices, these factors must also be considered in the analysis. The over-trucked situation at a mine will be discussed, i.e. when the number of trucks exceeds the optimum number of trucks a mine should have for the most productive/profitable mining operation. When the system has an excess number of trucks, truck utilization is reduced which impacts mine operation, capital costs and the environment, through unnecessary truck purchase, energy use, air pollution etc. A hypothetical surface coal mine layout was used for the simulation model.

Feb 23, 2014

By Z. Y. Hu

This paper reviews the past and presents the present state of industrial minerals in China. The resources, reserve and production of major non-metallic minerals are given. The mining and milling operations are reviewed. The future development and plans of Chinese non-metallic minerals industry are summarized.

Jan 1, 1990

By K. Zabrusky

Epithermal vein systems are often modeled as simple, discrete high grade structures within low grade host rock. However, geologic setting and structural preparation influence how such vein systems form. In structurally complex areas, veins may follow several structural trends and occur on a variety of scales. Geologic and grade modeling within such complex structural regimes can be difficult as individual veins cannot be delineated from host rock based on grade alone. Structurally complex areas require a different approach than traditional discrete vein modeling. Presented herein is a study of a structurally complex area that hosts vein mineralization to be mined underground. All veins could not be modeled discretely, so an alternate approach was needed. Major structures were modeled using surface and underground mapping and were then used to create a structural trend for the area. This trend was used to guide 3D grade shell construction. The grade shells replaced 3D vein solids for grade estimation in order to mitigate the influence of high grade samples. Structurally guided grade shell construction offers a more effective modeling method than discrete vein modeling in deposits that are structurally complex.

Feb 23, 2014

By M. A. Boucher

The purpose of my presentation is threefold: a) to make you aware of what is available in Canada in terms of refractory minerals. b) indicate the mineral deposits that have potential for development. c) show the advantages of Canada as a supplier of electrical energy necessary for the production of electrofused minerals. Canada is a producer of natural refractory minerals, electrofused minerals, and synthetic refractory minerals. Several deposits also have good potential for development. The natural refractory minerals produced in Canada are shown in Table 1. The major minerals by decreasing order of importance in terms of tonnage and values are: dolomite, graphite and magnesite.

Jan 1, 1992

By B. T. Darnton

Gravity concentration at the Pegasus Gold Montana Tunnels Mine was initiated in late June, 1991 with the commissioning of a coarse gold scalping circuit that processes a small portion of the ball mill circulating load. The primary objective for the circuit was to reduce the risk of gold particles advancing to flotation that are too coarse to float. The secondary objective was to enhance overall gold recovery and payable gold ounces in a cost effective manner. The gravity circuit has proven itself to be a major success. The above mentioned goals have been achieved, and they have been maintained at record throughput rates that are 30% higher than when the circuit was commissioned. A number of modifications and improvements were made over the last three years which allowed the gravity circuit to keep pace with the higher tonnage, these are discussed in detail in the body of this paper. The overall approach to gravity concentration at Montana Tunnels has always been to optimize production rather than maximize the gold ounces produced. This philosophy has now yielded a circuit expansion and relocation project which will allow for an estimated 50% increase in gravity gold production, while reducing the overall unit costs of production significantly. This paper will review historical gravity circuit performance, improvements, and the current relocation and expansion project.

Jan 1, 1995

By G. W. Phelps

This discussion deals with the geology o£ the Tennessee-Kentucky ball clay deposits; their mineralogy and chemistry; methods of finding, mining and refining; and makes observations on reserves of and future prospects for these clays. Ball clays appear in ceramic formulas for manufacture of vitreous china sanitary-ware, electrical porcelains, floor and wall tile, dinnerware and artwares(l). This type of clay is used for refractory (2) and abrasive products(3), and as a suspending agent for ceramic glazes(4), engobes(5) and porcelain enamel slips(6). Although some ball clay is imported, probably 85-90 percent of ball clay used in the USA(7) is obtained from deposits in Weakley, Henry and Carroll Counties in Tennessee(8), and in adjacent Graves County, Kentucky(9). The term "ball", as applied to clay, probably derives from former mining practice in England whereby conveniently-sized blocks of clay were cut from moist clay beds by spading(10), The expression "ball" has no other technological significance. ASTM(11) defines ball clay as "a secondary clay, commonly characterized by the presence of organic matter, high plasticity, high dry strength, long vitrification range, and a light color when fired." This, and similar(12) definitions, applies to English ball clays but is not satisfactory for many American ball clays. Geology of the Tennessee-Kentucky Ball Clay Deposits Figure 1 shows that most commercial clay areas of the eastern United States lie near the edge of the Coastal Plain; a skew-shaped configuration of its landward boundary outlines the Mississippi Embayment(13), Near the apex of this basin a broad plain, with a rolling, Bullied topography(14), dips gently westward from the Tennessee River to bluffs at the edge of the Mississippi River flood plain.

Jan 1, 1972

By P. Somasundaran, S. Venkatachalam, N. K. Khosla, K. Khosla

Froth flotation of alumina particles was studied by employing and hydrogen gas bubbles. The effect of current density was studied over a range of 0.1 to1.6 kA/m2. Compared to hydrogen, the use of oxygen bubbles at any given gas evolution rate resulted in a higher flotation recovery. The existence of an optimum current density, for each given particle size was indicated. Flotation at higher current densities resulted in better flotation kinetics, while flotation at lower current densities resulted in better Spas utilization.

Jan 1, 1996

By E. A. Domínguez

La Espingarda kaolin deposit was formed by ?in situ? alteration of volcaniclastic rhyolitic rocks belonging to Jurassic Marifil Formation. Three volcanic lithofacies were identified: porphyric biotitic ignimbrites (PBI), a coarse lithic ignimbrite (ILG), a fluidal intrusive rhyolite (RFI), all kaolinized in different degrees. The alteration covers an ellipsoidal area of ~20,000 m2, with its alteration decreasing downwards and disappearing at 8-12 m from the surface. The length to thickness ratio of alteration is 60:1. An erratic silicification was found as small zones (<3 m2) of quartz stockwork. The mineralogy is kaolinite + quartz + feldspars + Fe-oxyhydroxides ± halloysite ± illite and interstratified I/S, although the relative proportions change in each rock type. Due to coarse grain size and high quartz content, natural kaolin is unsuitable for slip cast ceramics, unless beneficiated. Washed ILG kaolin has the best rheological properties and behavior in casting and drying for its mineralogy, particle size distribution, thin texture and surface activity, as well as a certain fusibility and firing kinetics. PBI and RFI kaolins, due to finer texture, smaller grain size, lower surface activity, and higher halloysite amount, have worse slip viscosity and thixotropy that are due also to soluble salts. For the same reason, they have good casting and drying properties, but their purity brings about higher softening temperatures and water absorption. Several parameters are used to discriminate between hypogene or supergene kaolinite genesis. The hydrothermal genesis is mainly sustained by fluid inclusion temperature (150-180ºC) in quartz veinlets, while weathering is supported by deposit morphology, simple mineralogy, kaolinite stable isotopes (d18O ? 18, 13; dD ? ?59; ?85) and paleoclimatic record. It is concluded that a weathering process formed the main alteration with some participation of steam-heated meteoric waters. Neither the contents of Au, Ag, As, Sb, Hg, nor drill data support the existence of any epithermal gold mineralization at the kaolinite bottom.

Jan 1, 2010