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By Raul Z. L. Cançado, Virginia S. T. Ciminelli, Roberto Galery, Armando C. de Araujo

Brazil is presently among the seven largest gold producing countries in the world. This paper discusses the evolution of gold mining through the history of Brazil. It also gives a general account of the present practices for mining, processing and extraction of gold. Flowsheets of some selected plants are presented. The environmental aspects involved with gold production are also considered.

Jan 1, 1987

By Maurice C. Fuerstenau, Bruce R. Palmer, R. E. Johnson, B. R. Palmer, G. W. Warren

The environmentally sound processing of metal-bearing chloride solutions plays a key role in the extraction, plating, recycling, finishing and surface preparation of metals. Additionally, many chloride-bearing waste streams must be processed to obtain environmentally acceptable products. This paper reviews the technologies used for processing aqueous metal-chloride solutions and describes the challenges that have been overcome in application of these technologies.

Jan 1, 1993

By R. A. Paul

The requirements for water inflow control for the Chicago Intercepting Sewer System are stringent. This posed special problems in grouting the bored and conventionally mined tunnels, shafts and chambers of the system. In adapting conventional grouting techniques to the specific problems encountered in the system's pilot project, numerous field procedures were developed. Careful preand post-grout testing and evaluation identified the most efficient and economical of these procedures. As an example of some of the conclusions reached during the project it was found that the mineralized groundwater in the Chicago area tended to reduce the efficiency of the grout holes, thus limiting their useful life. Pressure washing to remove natural fillings was a critical factor in achieving a permanent grout seal. The value of relatively thin lubricating grout mixes was definitely established. Although not an ideal situation, satisfactory results could be obtained by manifold grouting several grout holes simultaneously if done within specific limits of hole groutability, location and numbers. Caulking proved to be a primary controlling factor in achieving acceptable results. To achieve such a high degree of water inflow control requires close supervision by experienced personnel. "Temporary grouting as a construction expedient" produces seepage conditions which are extremely difficult to treat.

Jan 1, 1974

By Tony Weeks, J. Loah, Ian Mcgaffin

PT Newmont Minahasa Raya (PT NMR) operates a 700,000 tonne per annum open cut gold mine in the Minahasa region of North Sulawesi. The operation commenced production in the second quaiter of 1996 and is expected to produce an average of 150 000 to 180 000 ounces of gold per year for the mine life. The deposit is predominately refractory in nature and requires a complex treatment route incorporating dry milling and whole ore roasting followed by conventional cyanidation and adsorp­tion of the gold onto activated carbon. Gold is eluted from the carbon to produce <lore bars assaying approximately 94 percent gold. A scrubbing system for the removal of mercury from the roaster off gases was commissioned in late 1997. Due to the location of the operation, close to the coast and in seismic region with high rainfall submarine tailings placement (STP) was the preferred method of tailings disposal. Prior to dis­posal into the ocean the tailings from the CIP plant are detoxified in a three stage detoxification circuit to treat cyanide, arsenic and mercury. This paper reviews some of the design and operational fea­tures of the whole ore treatment process employed at the Minahasa Gold Mine.

Jan 1, 1998

By R. F. Kovar, R. N. Torbin, R. E. Gundersen

I have to express my .surprise and must send a note of warning concerning the use of polyurethane foam as described in a paper by R.N. Torbin and R.F. Kovar, entitled "Innovative Shaft Lining Method," published in your February 1989 edition. In September, 1986, 177 miners lost their lives when they were exposed to fumes downwind from a fire in a tunnel lined with polyurethane foam. Whilst polyurethane exhibits reasonable fire retardent properties in small-scale tests, mass use in a tubular configuration, exacerbated by the furnace effect of cross-radiation, can lead to a rapid, uncontrollable conflagration. I do not wish these comments to detract from the engineering achievements of the authors but rather to sound a loud warning as to the application of the system. Any shaft designed for human access- be it for transport or shaft work - and any intake airway, should not consider the use of polyurethane foam. It only needs a slip with a cutting torch or an electric fault to initiate a disaster. Many countries have banned or restricted the use of polyurethane foam in the workings of a mine and maybe alternative foams (e.g. phenolics) can be used or developed

Jan 1, 1991

By Al Sylvester

The drill-and-shoot excavation of the two underground Pumphouses for the Metropolitan Sanitary District of Greater Chicago&apos;s Mainstream Pumping Station is described. The construction sequence involved the concurrent excavation and support of the two 19.2 m (63 feet) wide by 83.6 m (274 feet) long by 29.3 m (96 feet) high caverns. Excavation was interrupted after taking the 6.1 m (20 feet) high top heading in order to cast-in-place a 0.2 m (8 inch) thick by 19.2 m (63 feet) wide concrete arch. The remaining 23.3 m (76 feet) of rock was then excavated in benches below the concrete arch. PROJECT DESCRIPTION Twenty-four kilometers (15 miles) southwest of the city of Chicago, Peter Kiewit Sons&apos; Co., in a joint venture with John F. Shea Co., and Kenny Construction Co., has successfully completed the construction of the Mainstream Pumping Station for the Metropolitan Sanitary District of Greater Chicago. The five year, 169 millon dollar project is a vital component in Chicago&apos;s Deep Tunnel and Reservoir Plan in that its function is to lift the sanitary/ storm sewage back up to grade from 107 m (350 feet) below ground, and pump it to the treatment facilities 8 km (5 miles) away.

Jan 1, 1985

By I. Iwasaki, T. Fujuita

The removal of phosphorus from steelmaking slags is essential for recycling such slags to blast furnaces for recovery of their manganese, iron, and lime contents. Phosphorus is mainly concentrated in the dicalcium silicate phase of the slags (Fujita and Iwasaki, 1988, 1989; Suito, et al., 1977). Slow-cooling of steelmaking slags in an air atmosphere increased the grain sizes of constituent minerals; however satisfactory magnetic separation results could not be attained because of the close association of a strongly magnetic ferrite phase with dicalcium silicate (Fujita and Iwasaki, 1988). Curie point of the strongly magnetic ferrite phase in the slow- cooled steelmaking slags was investigated and an attempt was made to separate the phosphorus-bearing dicalcium silicate phase in ground slag pulps heated to a temperature exceeding the Curie point. Materials and methods Slag samples, heated to its fusion temperature of 1370°C and slow-cooled in an air atmosphere, were ground dry to -90 µm (about 170mesh) in a ring grinder. The ground sample was pulped to 1% solids in distilled water using 1 kg/t sodium hexametaphosphate as a dispersant and separated in a Sala high gradient magnetic separator, Laboratory Model 10-15- 20B, using a 100-mesh expanded metal matrix and 300 m/h flow rate.

Jan 1, 1990

By Ümit Yasar Onder, Tevfik Prof. Dr. Güyagüler

This paper describes the results of an investigation done to determine thermal properties and heat emission of coal measure rocks in Karadon district of Zonguldak Coal Colliery. In Karadon District, depth of working level is about -600 m where the heat problem arises. In the near future, workings will be at deeper levels and working conditions will be more difficult due to high heat emission. At the beginning of the paper the importance of wall rock heat emission in underground mine have been explained and then the amount of heat emission to the ventilating air has been calculated. It has been found out that the strata is the main source of heat in the mine. Therefore, geothermal gradient of the region has also been determined simply by measuring the virgin rock temperatures in different levels of the mine. All other data directly related with heat emission from different sources has been collected and has been analyzed by using a special computer package. As a conclusion, total heat and moisture content in ventilating air and heat balance has been determined for Karadon Coal Mine. In addition, some recommendations and suggestions have been made for the future works when the mine workings go to the deeper levels.

Jan 1, 1995

By Jaroslav Vicek, Alois Adamus

In the Czech Republic nitrogen was first used for the fight against the mine fire in 1949 (Hajek,1969). In the years 1949¬1996 the consumption of nitrogen in the Ostrava-Karvina Coal Basin /OKB/ reached more than 220 mil. m-3. The main source of nitrogen in the OKB is a central pipeline now. Gas nitrogen is used for the prevention of spontaneous combustion in gobs of longwall faces. The nitrogen infusion technology (Froger,1985), often called "franca technology", has been applied in the Czech coal mines since 1982. The aspects of the nitrogen infusion technol¬ogy can be theoretically solved by the calculation of mixing two gas streams in the filtration space. Longwall faces are parts of the ventilation network of the coal mine. The intake airflow of the longwall face is divided into the airflow passing through the face and a part of air losses passing through the gob. Air leakages through the gob and nitrogen in¬jected into the gob mix there. There is the main problem to solve air leakages in the gob. Usually, the principles of the gob aerody¬namics were used by many authors (Glusberg,1988;Voracek, 1994; Sulkowski,1993; Michailov, 1995; Dziurzynski, 1995; Kolarczyk, 1995; Saghafi, 1995; Sedlaty, 1993) that are applied to our case as well.

Jan 1, 1997

By Jean-Claude Bianchini, Paul Bauernfeind, Erwin Gartung

Introduction The city of Nuremberg, located in Bavaria in the Federal Republic of Germany, started building a subway in 1967. The construction operations began in a southern suburb, where no complications were encountered in the design and execution of the job. As the first subway line approached the downtown area of the city, the civil engineering challenges increased rapidly. Tunnels had to be excavated next to, or below precious historical buildings, and the work of the responsible engineers was closely watched by the public, who were very anxious about any damage to the existing beautiful old houses and churches. The job has been handled successfully to date in cooperation with the owner-designer, the geotechnical consultant and the contractors, who jointly went through a process of systematic learning and gathering of experience, and who developed a modern tunneling technique specifically tailored to the natural properties of the encountered ground conditions and the requirements of the city of Nuremberg. The application of scientific methods has been an important part of this development. Research into the geotechnical properties of the predominantly encountered soft Keuper sandstone, studies of the geomechanical performance of grout reinforced sand sections and finite element analyses of various tunnel problems for the prediction of displacements, for the assessment of stability, or

Jan 1, 1979

By James A. Strosnider

INTRODUCTION The Metro Rail Project is approximately a 20-mile initial portion of Southern California&apos;s planned 150-mile transit network and will provide transit service to the dense population and employment centers within the Los Angeles regional core. The Southern California Rapid Transit District (SCRTD) has defined, as the first segment, a 4.4-mile five station rail line, which extends from the yard and shop area near Union Station to the Wilshire/Alvarado Station. Design packages are completed; utilities are currently being relocated; demolition is underway; early construction contracts have been awarded; and construction has started. This paper will describe the current status of the Metro Rail design and construction, after first briefly reviewing its history, objectives, and main components. PROJECT HISTORY The California State Legislature created the SCRTD in 1964 with a legislative mandate to design, construct, and operate a rapid transit system within the Los Angeles County area. To obtain the monies required to support this program, in June, 1974, Proposition 5 was passed by a solid majority, allowing a portion of state gasoline taxes to be used for rapid transit development. This measure provided a local source of funds for SCRTD to begin its rail rapid transit development program in Los Angeles.

Jan 1, 1987

Controlled-blasting experiments in small development drifts were conducted at CANMET&apos;s Experimental Mine in 1992 and 1993. The objective of these experiments was to develop suitable controlled-blasting techniques for small development headings that are drilled by jackleg with 32-mm-diam holes. The experimentation was also aimed at providing insight into blast-damage mechanisms. Particular attention was given to the physical-mechanical properties of the rock and the rock-mass structural data. The drift faces were approximately 2.4 by 2.4 m (7.9 x 7.9 ft) in size with 36 to 43 holes drilled to a depth of 2.4 m (7.9 ft). Cartridged water gels, emulsions and semigelatin dynamite were used in the cuts and as primers, ANFO was used as the main explosive and decoupled 19-mm (0.75 in.) diam semigelatin dynamite charges were used in the perimeter holes. Smooth-blasting techniques and presplitting were tested in the underground mine. All of the blasts were monitored with a multichannel blast-vibration monitor, to which was attached sets of high frequency geophones and accelerometers. These experiments demonstrated the efficiency of controlled-blasting techniques for the reduction of blast damage and also demonstrated the need to improve the safety and efficiency of using explosives.

Jan 1, 1997

By R. J. Lutton

The suitability of large-stone materials continues to present occasional problems in US construction. Distinctive modes of rock deterioration cracking, spalling, delaminating. disaggregating, disintegrating, and dissolving help to distinguish causes of deterioration. Design requirements, costs, and environmental factors remain critical to performance. The rating of material quality from superior hypes such as granite to marginal types such as conglomerate is too simplistic but may be useful in a preliminary way. Regardless, the market is dominated by limestone/dolomite material types because of their widespread availability. Certain tests that have been standardized are widely accepted and used for evaluating stone as riprap and armor. These tests are adapted from those used extensively for concrete aggregate; they explore the resistance of the rock to destructive processes such as abrasion, freeze-thaw, and wet-dry environmental attack. The field evaluation of the rock source is often as important as testing. Important limitations imposed by natural jointing and variations of bedding are documented in this manner. The field examination also supports the testing by estimating how much of the quarry is rep¬resented by each of the samples to be tested. Finally, quarrying and processing methods and transportation are carefully considered in regard to stone quality, average size, size gradation, and cost.

Jan 1, 1990

By Michael E. Salovich

The U. S. Department of Interior, Bureau of Mines (Bureau) has developed a prototype version of a computer application that combines hydrologic analysis with object-oriented graphics. This software is unique in that it presents analytic element analysis within an object-oriented CAD environment. Its user interface employs mouse handling, scrolling windows, dialog boxes, palettes, and pulldown menus. It can import scanned images of maps and overlay these images within the same window. This application was developed using object-oriented programming techniques. Several programming issues concerning graphics had to be resolved during development of this system. These include (1) how to represent hydrologic elements as graphical objects, (2) how to translate screen coordinates to map coordinates, (3) how to implement ?zooming? (changing the magnification level of a window), (4) how to overlay layers of images, and (5) how to import scanned images of maps. An object library was used to implement graphical user interface features such as scrolling windows and pull-down menus. Algorithms for CAD features such as map coordinate translation, zooming, and the layering of images were developed by Bureau researchers. The application has a modular source code structure and can be modified for use in other research applications.

Jan 1, 1992

By John R. Keith

Keith, John R. 1968. Relationships of lead and zinc contents of trees and soils, Upper Mississippi Valley District. Preprint, Fall 1968 Meeting, Soc. Mining Engineers of AIME. Lead and zinc contents of elm, maple, and oak trees and of soils in which the trees grew were determined in samples from the Upper Mississippi Valley mining district, and from an area outside but contiguous to the district. The lead and zinc analyses of plant materials served to differentiate the mineralized and non-mineralized areas. Stems contained about two times as much lead and about 2-5 times as much zinc as did leaves taken from the same stems. Lead and zinc analyses of all soil horizons could be used to differentiate between the two areas. Soils at most sample sites in the mineralized district seemed to be more reliable than plants for geochemical prospecting and are a more practical sampling medium. Soil samples from areas with thick loess cover, however, failed to indicate the presence of mineralized bodies whereas tree samples from the same sites contained anomalous amounts of lead and zinc. It is suggested that in areas of thick loess cover plant samples could be used in prospecting for lead and zinc.

Jan 1, 1968

By Hans-Christian Kurzweil, Klaus Mussger

CERN, the European Laboratory for Particle Physics, are upgrading their existing particle accelerator for the next generation of experiments and have three major packages of underground construction work in progress. Each package involves the construction of shafts, cavern, tunnels and surface buildings. This paper gives an overview of CERN, the LHC Project and a more detailed discussion of design process, design review and construction works of Experimental Point 5. The LHC works at Point 5 include two large shafts, two major parallel caverns with a total span of 50 m, which are separated by a 7 m wide and 28 m high concrete pillar, and a system of secondary tunnels and caverns. The overburden ground consists of around 50 m of water bearing moraine (silty, clayey gravels and sands) overlying 20 mof molasse, which consists of horizontally bedded marls and sandstones. The shaft shave been constructed with ground freezing, primary concrete lining, membrane and secondary slip formed concrete lining. The concrete pillar was then excavated and concreted in advance of excavation of the two caverns. Cavern construction includes primary support of shotcrete lining and rock bolts, followed by waterproof membrane and primary support of shotcrete lining and rock bolts, followed by water proof membrane and insitu concrete secondary lining.

Jan 1, 2003

By J. P. Ramsey

This is a description of the efforts of a research project intended to demonstrate methods of alleviating pollution from coal mine refuse piles and slurry lagoons. These are mainly derelict barren sites. Some are burning and some are vulnerable to wind erosion which causes air pollution. Some occupy valuable land near metropolitan areas. They are an integral part of the landscape of the Appalachian and Midwestern Coal Fields. They are important in the light of growing civic awareness of the great general problem of waste disposal and environmental improvement. In the V-shaped valleys of the Pocahontas Region, they continue to be piled higher and higher. In flatter topography, they tend to form broad, flat ridges. Some contain more metal forms than others and some have a minimum of metal, but weather to a fine talc, which chokes streams with a fine particle suspension. Most are burning or have burned, but burning or weathering, most all are sources of pollution to the atmosphere and to adjacent waterways. This demonstration project is being carried out at an abandoned mine near the town of Du Quoin in southern Illinois. It is jointly sponsored by the Truax-Traer Division of Consolidation Coal Company and by the Federal Water Pollution Control Administration of the Department of the Interior. The site area is a refuse pile and slurry lagoon, each of fifty acres. It is hoped that basic data from this study will be generally applicable to other sites and will provide a basis for rational and efficient engineering design of future reclamation projects. Most refuse piles have extremely long term capabilities to produce highly potent acidogenic oxidation products typifying the more serious aspects of acid mine drainage contamination. Numerous sites remain where the abandoned mine no longer discharges acid waters, but its associated refuse pile continues to generate significant quantities of acid and other oxidation products even after many years.

Jan 1, 1969

By C. Salcedo, J. Vallance, J. Sáez, M. Robles, J. Spangenberg, S. Rosas, L. Fontboté

The Tambomachay ore deposit (13°28'36.78"S, 71°57'35.98"W, about 6 km north of the town of Cuzco, Peru) consists of Cu hosted in arkosic red beds of the Kayra Formation (Lower Eocene). Bornite, chalcopyrite, chalcocite, covelite, digenite, malachite, and chrysocolla occur disseminated in thin layers and in veinlets. The occurrence of the copper ores in a part of the red bed sequence containing green reducing layers, the presence of organic matter in interstices between the hypogene sulfides, and the sulfur composition of the copper sulfides (δ34S values between -16.9 and -12.4‰ vs VCDT) pointing to bacterial sulfate reduction, are strong arguments to propose that mineralization was caused by copper-bearing oxidizing saline basinal fluids that precipitate copper sulfides when they meet reduced sulfur in an organic matter-rich horizon. Faults parallel to the regional Tambomachay Fault could have acted as feeders for oxidizing basinal copper-bearing fluids. Fluid migration was probably driven by tectonically-induced topography gradient. INTRODUCTION A number of red bed Cu occurrences are known in the Cuzco region in the early Eocene – early Oligocene San Jerónimo Group (Gregory, 1916; Carlotto et al., 1996, 2011; Loza et al., 2004). In the past, copper ores were extracted in several small-scale mines in the surroundings of Cuzco, including Tambomachay, Tipón, and Zurite in the Cusco province and Ushpa, Guilda, Giovanna, and Langui in the Sicuani Province. The abandoned Tambomachay Mine (13°28'36.78"S, 71°57'35.98"W), about 6 km to the north of the town of Cuzco (Romero et al., 2015; Salcedo et al., 2017, Fig. 1) was chosen as the main site for the present research aimed to better study the genesis of these copper occurrences. Results deriving from fieldwork, microscopic characterization of ore and host rock, and sulfur isotope determination suggest that the key factor for the genesis of the copper ores is that copper transported by oxidizing basinal fluids is trapped by reduced sulfur of bacteriogenic origin located in a part of the red bed sequence that shows intercalatins of green reduced horizons.

Jan 1, 2019

By Angela K. Braden

Igneous rock exposures occupy only a minor portion of surface area (<18 mi2) in Arkansas, and are divided into two major groups: nepheline syenite (7 mi2) and syenite complexes (8 mi2), with various dikes and sills representing the remaining surface exposures. The syenite complexes have been the sites of major vanadium and minor titanium production during the past 50 years. Nepheline syenite exposures were important in the early production of locally used building stone; however, aggregate and roofing granules have now become the principal market for the production of nepheline syenite in Arkansas. Nepheline syenite intruded into a sequence of Paleozoic sedimentary rocks in Arkansas and is exposed in two areas: in Saline County near the town of Bauxite, and in Pulaski County at Granite Mountain, just southeast of Little Rock. Although the central Arkansas region had been investigated thoroughly for bauxite by the early 1950s, the nepheline syenite resources of the region have yet to be evaluated systematically by the state. Arkansas nepheline syenite was evaluated for its ceramic uses in 1952. Some recent industry interest has revolved around its potential use as a sand-blast abrasive. The largest exposed areas of nepheline syenite, located at Granite Mountain, currently are being mined by the Minnesota Mining & Manufacturing Company (3M) and McGeorge Contracting (Granite Mountain Quarry). 3M has been in operation since 1947 and mainly produces roofing granules. A fine powder produced by 3M during crushing that is marketed under the name Donnafill? recently has seen use as filler in self-compacting confined construction and as an additive (frit) in common brick. Since the early 1960s, Granite Mountain Quarries has produced a variety of aggregates, ranging from riprap to industrial sand, and recently constructed a computerized hot-mix-asphalt production facility. Approximately 4.5 million tons and 1.2 million tons of syenite were produced from Granite Mountain and 3M, respectively, during 1979. No production values are available after this date; however, combined production from both quarries is estimated to be at least 6 million tons annually.

Jan 1, 1999

By Kaye P. Strong, Desmond M. Levins, Anthony G. Fane

1. INTRODUCTION The safe disposal of tailings is the most important environmental question facing the uranium mining industry today. This is because tailings present a major long term radiological hazard as they contain about 71% of the radioactivity originally in the ore. The magnitude of the problem can be appreciated by considering the quantity of tailings involved. For example, projections of milling programs in Australia indicate that there will be 100 million tonnes of tailings produced by the year 2000 (Levins 1980). The United States currently has in excess of 100 million tonnes and by the year 2000 will have between 900 and 1700 million tonnes (Landa 1980). Present options for tailings rehabilitation include leaving them above ground, returning them to the mine or placing them in specially excavated pits. In any event, the tailings will be covered with earth and revegetation attempted. This will remove the problems of airborne radioactive dust and water erosion of the tailings, at least in the short term, but diffusion of radon-222* from the tailings may still occur. The Atomic Energy Control Board of Canada (1981) has proposed a maximum allowable radon flux from rehabilitated tailings of 0.074-0.37 Bq m -2s-1(2-10 pCi M-2 s-1); the exact level is to be determined "after discussion with other regulatory agencies and the industry". The United States Nuclear Regulatory Commission (USNRC 1980) has been more restrictive in recommending a maximum flux of 0.074 Bq m -2s-1 (2 pCi m-2s-1). As a guideline they also suggested a minimum depth of covering material of 3 m to achieve this surface flux for tailings typically found in the western milling regions of the United States. The design of rehabilitation schemes is aided by a knowledge of radon transport through tailings piles. In this paper we present the results of a theoretical analysis and experimental study of radon diffusion through selected Australian tailings and cover material. The minimum cover criteria of 3 m is reexamined in the light of these findings. [ ]

Jan 1, 1981