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By E. Topuz, J. Mastoris

The problem of defining the optimum final limits of an open-pit mine has challenged the mining industry for the last three decades. The difficulty results mainly from the great number of variables involved and from the sheer computational effort required in real-life applications. An actual lignite deposit is used in this study to introduce and apply a new methodology that can be used as a basis for surface-mine design optimization. A geologic-reserves model of the deposit is first developed with the use of an integrated geostatistical-modeling package. The model is transformed into an economic one through the use of flexible objective function formulation(s). The final open-pit limits are then optimized using a competent commercial optimizer, and comparative-sensitivity analyses are performed to study the effect of some basic mining and economic parameters on the optimal pit design. The conclusions drawn can develop useful guidelines for decision making by the mine operator.

Jan 1, 1996

By R. Vergunst, E. A. Devuyst, G. Robbins

By the middle of 1989 Inco will have applied its patented cyanide removal technology to seventeen commercial operations. Removal of cyanide from CIL slurry tailings is applied at Equity Silver and Inco's new 1.200 mtpd mill at Inco/Golden Knight. Detoxification of CIP tailings is carried out by Colosseum California (3.600 mtpd), Canamax's Ketza River (360 mtpd) and Westmin's Silbak Premier (2000 tpd) operations. Repulped tailings from Merrill-Crowe flowsheets are treated at Total Erikson's Mount Skukum (300 mtpd) and Skyline's Johnny Mountain (200 mtpd) mills and barren bleed at Inco/Queenston's McBean mill (500 mtpd). Lynngold's MacLellan mill (1800 mtpd) and ERG (40.000 mtpd) treat pond supernatant water. Plating shop cyanide effluents are decyanized at Kuntz Electroplating and two other plating shops in Ontario. Details regarding some of the above operations are given. Operating and capital cost estimates for various treatment options are discussed.

Jan 1, 1989

By John E. Litz, Charles W. Kenney, Wayne Carter

Refractory gold ore pretreatment processes continue to receive much attention. This paper compares the relative economics of treating ores by oxygen pressure oxidation, roasting and bacterial oxidation with or without preconcentration by froth flotation. Capital and operating cost estimates for each method of pretreatment were prepared and these estimated costs and ore sulfide grades then are used to compare the process economics. The study indicates that the most significant item affecting the economics is the amenability of the ore to flotation. The cost benefits of flotation are $10-13 per tonne ore processed (2%-4% s=, 10:1 ratio of concentration). In most cases bacterial oxidation has the lowest overall cost, especially if less than complete oxidation of the sulfides will give acceptable recovery, however bacterial oxidation has yet to be practiced on a large scale. In all situations pressure oxidation shows the highest cost. However, the cost differences between the treatments are small, less than $7 per tonne.

Jan 1, 1990

By Felicia F. Peng

Two modes of collector addition techniques are applied in the column flotation for cleaning ultra fine coal. The collector can be: 1) added directly into the coal slurry through the feed system; and 2) gasified collector and transported in the gas phase through the bubbles. Operating parameters of the column flotation were investigated through three phases of work plans for Pittsburgh No.8 seam coal. In present study, the column flotation using two modes of collector addition techniques were tested and compared. Ninety percent or higher combustible recovery can be achieved by using both methods. However, utilizing the gasified collector addition technique in column flotation has more potential than direct liquid addition technique to obtain the higher recovery at same collector dosage.

Jan 1, 1993

By Betty L. Gibbs

A short course, held during the SME Annual Meeting in Phoenix, AZ in February, focused on software for surface and underground mine modeling. The objectives of the short course were to review techniques for surface and underground mine planning. Mine planning software vendors were invited to demonstrate how their software runs, given a standard data set. Six vendors of mining-specific software participated in the workshop. They were Exploration Computer Services (MINEX 3D), GEMCOM Services, Inc. (PC-MINE), KJRA Systems (VULCAN), Mine Development Associates (SURPAC), Micromine and MINEsoft (TECHBASE). Data set A data set was created to challenge the capabilities of each vendor's software. The criteria used for the data set selection were: • a minimum of 300 drill holes; • the data must include topography, drill hole survey, assay and formation contacts; • the deposit was multimetallic; and • there was the potential to be mined by surface and underground methods. The data set used was an actual, complex copper ore body with a small amount of gold. The ore body was close enough to the surface to be mined by surface techniques. Part of it, though, was also amenable to underground mining. To further complicate the problem, a river ran across the area of the ore body. This presented mine planners with the problem of either moving the river or mining around or below it. The ore body had not been mined, so no data was available for the tons and grade actually produced. Data for the mine planning problem was distributed to each vendor about two months before the short course. They had the opportunity to load the data into their systems, build an ore body model and perform preliminary work. During the first day of the workshop, the vendors received problems concerning the ore body. They went to work on their machines, attempting to show short course participants how their software could help solve the problem.

Jan 1, 1992

By F. Michael Wahl

With the exception of reports on commercial deposits of kaolin, fuller's earth, and other specialty type clays, there is little published information on the extent, properties, and potential uses of the clay resources of Florida. Recent studies by the Florida Bureau of Geology in cooperation with the University of Florida and the U.S. Bureau of Mines have proven the existence of two extensive Miocene clay deposits, one in peninsular Pinellas County and the other in southeastern Charlotte County. Drilling and subsequent testing of the clays from these deposits indicate their potential for economic development. Both deposits consist of montmorillonite type clays, have an average thickness of 25 to 35 feet, and are overlain by unconsolidated Pleistocene sediments. Preliminary firing tests indicate that the clays from Pinellas County are a potential raw material for lightweight aggregate production. The clay has good bloating characteristics across an acceptable temperature range with a resultant aggregate density of less than 1.00 specific gravity. The clays from Charlotte County have poorer natural bloating characteristics but might well be used after treatment or with additives. The economic potential and locations of both deposits emphasize the need for locating similar clay resources in the state that might have economic potential so that land use planning and subsequent urbanization will not prohibit their development.

Jan 1, 1972

By Jon Bowler

Daw Mill Colliery, UK Coal, near Coventry in England, mines the Warwickshire Thick Seam at 800 m/2500 ft depth using longwall retreat with gateroads supported by rockbolts. Over the last eight years the mine has worked longer and wider panels with extraction heights of over 5 m. Recently the mine has experienced high deformation conditions principally from the rib sides resulting in operational issues and production delays. Investigation of rib deformation was undertaken using new inspection and measurement techniques, including systematic laser surveying, and improved rib support consumables were developed and introduced. A new rib trussing system using textile webbing has proved very successful.. A rib support management system was also developed and introduced for face retreat. This allowed rib support to be more effectively managed both for production and safety. For the current developments, new 28-mm-diameter roof and rib bolt systems have been introduced and rib bolt length has been increased to 3 m, with the aim of achieving gateroad stability over the life of the panel. Significant reductions in roof and rib deformation have been confirmed by the latest monitoring results. These ground control innovations are allowing Daw Mill?s potential to be realised. Production from 302?s face in 2008 set new UK and European records. However the support enhancement process continues and further innovations are planned.

Jan 1, 2009

By S. D. Bearden

China was the world’s leading producer of barite during 1995 with 35%. The United States followed with14%. India produced 9%. Other producers included Morocco, Turkey, Mexico and Germany. Domestic production of barite during 1995 was estimated to be 600 kt (660,000 st). Nevada produced 85% of the total. Georgia was the second leading barite-producing state. The United States is the world’s largest consumer of barite. During 1995, it used 1.6 Mt (1.8 million st). US reliance on imported barite during 1995 was about 63%of total consumption, according to the US Geological Survey.

Jan 1, 1996

By Eero Pokki

The Päijänne Tunnel is being constructed to conduct raw water from Lake Päijänne to the Helsinki Metropolitan Area. The length of the tunnel will be 120 km and the cross-sectional area is 15.5 sq m. Excavation started in 1973 and will be completed in 1982. 94 km of the tunnel have been constructed from Lake Päijänne towards Helsinki. The construction has advanced according to plan, and due to Finland's hard bedrock there have not been any great surprises. When completed, the tunnel will meet the water requirements of the Helsinki Metropolitan Area for a long time in the future because, with a free fall of 36 m, 9.6 cu m/s of water can be conducted through the tunnel from Lake Päijänne to the Helsinki Area. With pumping it will be possible to obtain a flow of 15 cu m/s, although at first the discharge will only be 5 cu m/s. The tunnel was partly taken into service as early as March 1979 when it was possible to conduct water to the municipalities north of the Helsinki Area. It is already possible now to conduct water to Helsinki, too, but from the Korpimäki pumping station onwards it must be done through the River Vantaa, which is polluted. When the tunnel is completed in 1982, good quality water can be conducted from Lake Päijänne to the Helsinki Metropolitan Area through a continuous rock tunnel. The cost estimate in 1973 was $ 88 million while it is now $ 90 million notwithstanding high inflation. AREAS NEEDED FOR CONSTRUCTION The areas needed for construction were bought through voluntary deals. Areas of 4 - 5 hectares were bought along the tunnel line at about 5 km intervals. The excavation of access tunnels was started from these places, and the crushed rock from the main tunnel was also transported there. However, it was not necessary to buy the area

Jan 1, 1979

By H. F. Haller, H. C. Pattison

The research program described in this paper is sponsored by the Advanced Research Projects Agency of the Department of Defense and monitored by the Bureau of Mines, United States Department of the Interior. PROGRAM DEVELOPMENT While Holmes & Narver is better known in other fields, the company has been active in many phases of underground excavation for over twenty years. In the 1950's, H&N participated in design and construction of nearly twenty miles of waste disposal tunnels in Southern California. As Architect-Engineer for the Atomic Energy Commission, we had design and management responsibility for many miles of tunnels and for thousands of feet of exploration and big hole drilling, from coast to coast in the States, and for gas well completions and exploration drilling for the Navy and the National Science Foundation from Pt. Barrow to Byrd Station in Antarctica. In my ten years with the company, we contributed to the development of big hole drilling techniques at a number of sites and analyzed the capability of boring machines for many of the tunnel projects. In a 1965 engineering study of a hundred miles of vehicular tunnels in rock under New York City, we investigated

Jan 1, 1997

By Michelle Mangione, John Kuyt, Zili Li, Michael Mooney

"Twin bored tunnels are commonly used for a variety of road and tunnel projects throughout the world.A major component of these twin tunnel projects is the construction of connecting cross passages that provide emergency access between tunnels and space for tunnel service equipment. Cross passages can present significant geotechnical risk and technical challenges to a project – support systems must be considered for redistributing loads around the mainline tunnel openings and supporting new loading resulting from excavation activities. Additionally, cross passages pose risks to construction schedule and cost because of their sequencing at the end of construction, so mitigation of schedule overruns can be critical. By observing field instrumentation data records from completed projects, a better understanding of the force development in each temporary structure can be achieved with indication of which structures are the most critical to support ground loads.This article discusses the data obtained during the Brisbane Airport Link construction project, a road tunnel located in Brisbane, Australia. Strain gauge instrumentation data from the precast segmental lining and propped opening steel sets is presented with relation to the construction sequence and local geology. Interpretations and conclusions based on the observed trends are proposed, with several key mechanisms affecting the loading and unloading identified.Brisbane Airport Link project overview. The Brisbane Airport Link project in Brisbane, Australia, connects central Brisbane to the airport located northeast of the downtown with more than 7 km (4 miles) of twin-bore road tunnels, two lanes each, with several caverns, interchanges and access ramps constructed along the alignment to connect to other key routes in the city. The project was executed under a public-private partnership (P3) scheme, funded and operated by the consortium BrisConnections. The main contractors were a joint venture of John Holland and Theiss, while the design was carried out by Arup and Parsons Brinckerhoff.Construction of the tunnels was conducted using a combination of 17 roadheaders and two 12.5-m (41-ft) double-shield Herrenknecht tunnel boring machines (TBM) (Harding & Francis, 2013). The TBMs were used in earth pressure balance- (EPB) type closed mode for the initial portion of their drive, starting at the northeast end of the alignment. Tunneling started in soft ground, weathered rock, and mixed face conditions initially, progressing to competent sedimentary rocks as the drive continued. Support was accomplished using a 12.1-m (39.8-ft) diameter steel fiber reinforced concrete (SFRC) segmental lining installed behind the TBMs in nine segments + one key arrangement. The innovative design of these segments is detailed in the paper by Harding and Francis (Harding & Francis, 2013). Ancillary roads and underground interchange caverns were constructed by sequential excavation techniques using roadheaders, accounting for nearly half of the total underground excavations."

Mar 1, 2017

By Silvano Perla

Peabody Western Coal Co. operates two mines in northern Arizona. The Black Mesa and Kayenta coal mines are unique for several reasons. They both have only two customers: Southern California Edison’s Mohave generating station near Laughlin, NV and the Navajo generating station near Page, AZ. Both mines are close together. Between the two, they ship nearly 11 Mt/a (12 million stpy) of coal. Material is shipped to the power stations in two ways. This first is a 440- km-long (273-mile-long) underground slurry pipeline, the longest in the world. The second is an 11 -km-long (17-mile- long) long conveyor to four storage silos. Product is then shipped by train from the storage silos to the plant sites. Another factor makes these mines unusual. They are both situated in the middle of the 68,795km2 (17 million- acre) Navajo Reservation, home to the Navajo Nation and Hopi Tribe members. Nearly 90% of the Black Mesa and Kayentamines’ 850 employees are tribe members. Peabody Western Coal is the United States’ largest private employer of Native Americans.

Jan 1, 1995

By John Marsden

JIM ARNOLD: Our next speaker is John Marsden. John runs the concentrator complex at La Candelaria Project in Chile. John's a Royal School of Mines graduate and he wrote the book on gold metallurgy, The Chemistry of Gold Extraction, which, by the way, he dedicated to me-at least that's what my copy says. [laughter] John, go ahead. (Message shown on Projection screen) ‘Raulerson’s Rules Plant operators and maintenance personnel should be asked to participate early in the design process. This ensures that the plant will never be completed on time or within budget.’ JOHN MARSDEN: Good afternoon, everybody. My presentation this afternoon is going to be very short. It won't be as funny as Joe Keane's, but I guarantee you it will be a lot quicker. [laughter] That transparency isn't mine, actually. [laughter] You're trying to throw me off.

Jan 1, 1998

By F. M. Doyle, Jun Li, Milton E. Wadsworth, Ximeng Zhu, E. Peters

The electrochemical behavior of pyrite in borate/sulfate solutions was investigated using cyclic voltammetry. Three anodic peaks at approximately -0.8 V, -0.1 V and +0.5 V (SCE) were detected along with their corresponding reduction peaks. The first two peaks correspond to the oxidation of surface products. The third peak corresponds to the direct oxidation of pyrite with reaction products FeO oxides. sulfate ion and partially oxidized sulfur intermediates present as a surface film of polysulfides and So. The Few oxides and sulfur intermediates were reduced to ferrous hydroxide and HS during the negative-going scan. The HS interacted preferentially with Fe(OH), on the surface to form FeS. Excess fenous hydroxide continued to reduce to metallic iron. During the return positive-going scan, metallic iron was oxidized to ferrous hydroxide and FeS was oxidized to pyrite. These reactions are characterized by a unique double peak observed in the region -0.8 to -0.65 V. The growth kinetics of the surface sulfur film formed during anodic oxidation were studied using chronoarnperomeay. Potentiostatic measurements were well correlated by a paralinear rate equation, suggesting the formation of an intermediate passive film, associated with the simultaneous dissolution of the outer layer of the film. The reaction rates were affected by applied potential, solution pH and temperature, but were independent of electrode rotation speed. A reaction kinetics model which fitted well with experimental results, was developed.

Jan 1, 1993

By Song Xiaotian

Studies have been carried out to optimize the VCR's mining sys- tem on the basis of synthetic analysis at Fankou Pb-Zn mine in Southern China. The synthetic e- valuation method is proposed for selection of mining alternatives and stope dimension optimization techniques. Theoretic calculation and computer optimization of the fragmentation of rock blasted by multispherical explosive charges are discussed. The mathematical and optimal fragmentation models are built. The optimum model is built for the main mining operations such as drilling, blasting and haulage. Lt can be used to evaluate VCR?s mining projects, select mining parameters and provide design fundations. From the point of view of system research on the geomechanical process, stoping technological process and benefit, the complex method of optimization is proposed for VCR's mining. Using computer simulation, based on this model, the optimal parameters are established and analysed. An effective approach is provided for research on the mining method optimization and getting better economical benefits from the application and improvement of VCR's method.

Jan 1, 1986

By Charles W. Daugherty, Eugene B. Waggoner

In the construction of recent subsurface projects, particularly mined openings and transit systems, it has been apparent that final costs were often greater than first expected. Because many overruns result from alleged differing site conditions, there was reason to suspect that pre-bid geotechnical investigations were inadequate for predicting subsurface geology. In 1982, nine federal agencies involved in constructing underground facilities funded the National Academy of Sciences' U.S. National Committee on Tunneling Technology (USNC/TT) in an effort to evaluate and clarify the relationship between geological knowledge and construction costs. That committee formed the special Subcommittee on Geological Site Investigations, which spent more than two years studying underground projects by examining contract documents and geologic reports, making site visits, and interviewing owners, designers and contractors. The study ultimately encompassed 84 mined tunnels and chambers and three deep shafts in the United States and eastern Canada. Data collected on geologic exploration, design and construction were analyzed and conclusions reached concerning whether and how site investigations need to be improved. The results of the study are published in two volumes by the National Academy of Sciences. Due to the recent completion date of the main report, it was not possible to prepare a summary for inclusion in the RETC Proceedings. However, the complete two-volume report, "Geotechnical Site Investigations for Underground Projects," can be obtained by writing or calling: U.S. National Committee on Tunneling Technology National Academy of Sciences 2101 Constitution Avenue, N.W. Washington, D.C. 20418 (202) 334-3136

Jan 1, 1985

By J. Kulczycka

Poland in time of transition had been dealing with the remnants of the previous regime ? particularly in the field of environmental protection. The burden left was tremendous and there was a need for fast and effective tools for improving the environment. The idea of environmental protection had been supported by the introduction of a new environmental policy that underlined the importance of sustainable development in industry in the beginning of 1990s. This policy introduced high environmental fees and fines ? a concept not very popular in Europe in that time ? and good only for a country in transition to boost the protection of the environment. While this policy had its role to play, its role is now completed. It is time to move forward, especially when these environmental charges affect the international competitiveness of industries so much, and at the same time have virtually no influence on environmental protection investments any more.

Jan 1, 2005

By Michael G. Nelson, Sekhar Bhattacharyya

Between 1974 and 1977, a detailed study of coal pillar strength was conducted by the University of Utah at the Beehive mine in southeastern Utah. This study was funded by the U.S. Bureau of Mines, and included laboratory testing of coal samples, extensive field instrumentation and measurements, and finite element analyses based on the laboratory results. Recently, a similar analysis of the laboratory results and mine design geometry was completed using the LAMODEL program developed by NIOSH. The results of this analysis were close to the data collected in the field. This study allows comparison with the earlier finite-element analysis, and illustrates the utility of the LAMODEL software suite.

Jan 1, 2005

By R. W. Smith, Z. Sadowski

INTRODUCTION Problems encountered in barite flotation from various waste materials such as spent drilling muds are likely to be closely connected with the effect of contaminant metal ions and other chemicals on the flotation. Investigations on the recovery of barite from tailings ponds and mining wastes (Sullivan and Lamot, 1981) have shown that such barite materials can contain large quantities of carbonate and silicate minerals (including clay minerals). Also iron oxide slimes can be present. From these substances, cations such as Ca2+, Mg2+, Fe2+, and A13+ can potentially dissolve and be present in the aqueous phase accompanying the various minerals. These ions and their hydrolysis products can have a substantial effect on any subsequent flotation scheme. The present study investigates the effect of the noted ions on both the stability and electrokinetic behavior of barite suspensions. Some adsorption (abstraction) experiments were also performed. Experimental materials and methods The barite used was a high-purity, naturally occur¬ring mineral sample (Kings Creek, SC). The material was ground in a porcelain mill and a fine fraction (mean particle size 11.49 µm) separated out by air elutriation. The mean size was determined by an aqueous sedimentation method using a CAHN electro-balance. In the method, an 0.6-g sample of the barite was dispersed in 450 cm3 of pH 7 water containing 0.01 g of sodium tripolyphosphate. The mean particle size was denoted X0. The stability of the barite suspensions was determined by a comparison of the mean size of the investigated barite suspension aggregations with the mean size of barite powder determined in the presence of sodium tripolyphosphate. The mean sizes (X) of the barite aggregations were determined using the same amount of water and barite sample as in the measurements of dispersed barite particle size but without the presence of polyphosphate. The ratio X/Xo is thus a measure of the stability of a suspension (the greater the ratio, the less stable the suspension). The adsorption (abstraction) experiments were carried out in polyethylene bottles containing 1 g of barite powder in 200 mL of solution. The solids were added to a solution containing a known concentration of metal chloride salts (AlCl3, FeCl2, MgCl2, and CaCl2) . The pH was controlled by both HCl and NaOH addition. The suspensions were agitated in a shaker for three hours. The final ion concentrations in solution were determined by atomic absorption analysis. The electrokinetic measurements were made using a Komline-Sanderson Zeta Reader in a conventional manner. All experiments were carried out in the presence of 1.0x10-3 k.mol/m3 NaClO4. Experimental results Figure 1 shows the zeta potential of barite particles as a function of pH in the presence of iron(II). The

Jan 1, 1988

By W. G. Cornwall

The mining field, inclusive of the treatment plant is located in the foothills, five miles inland from the northern coast of Viti Levu, the largest and most important island of the Fiji Group. Gold and silver occur as tellurides, associated with the sulphides, and as minor occurrences of electrum.

Jan 1, 1975