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By Jeff Reid, Mohamed Maghari, Nicholas Joens

The Burnaby Mountain Tunnel was an integral part of the Trans Mountain Expansion Project. General Contractor, Kiewit Ledcor TMEP Partnership (KLTP), contracted with McNally Construction to build an underground tunnel between the Burnaby and Westridge Marine terminals under Burnaby Mountain. The pipeline was constructed within a 2.6-kilometre tunnel, eliminating the need to run the pipeline over the mountain and minimizing community impacts. The complexities of this Project led to multiple innovations, including the design of a Tunnel Boring Machine (TBM) capable of excavating through mixed-faced conditions concurrently thus allowing the Project team to complete the tunnel with limited geotechnical information.

Jun 23, 2024

By Edwin J. Connell, O&apos

Investment in mining and related process facilities will be more costly and complex in the 1980s than ever before. Interest rates and inflation are soaring; regulations are expanding; and in order to achieve economies of scale, plant facilities and mines are getting larger. As the pace quickens, the time/cost circuit closes around the resource owner or developer. Larger modern projects cost more money and take more time to build. The longer it takes to bring a project onstream, the more it costs in interest, escalation, and lost production. One solution to the time/cost squeeze is to take advantage of systems developed by major contractors serving the mining industry. These contractors have been serving clients in planning and executing large and small projects for many years. They have developed systems which, if applied at an early point in the project's life, can be a significant benefit in development of mineral resources. The systems involve performance of feasibility studies, economic evaluations, and the project installation itself. First the Feasibility Study Feasibility studies can minimize risk through systematic evaluations while progressing toward the ultimate objective-an operating plant. Normally, studies are initiated with a minimum amount of specific information and a maximum number of as¬sumptions. Through the course of the study program, assumptions are continuously confirmed, refined, or rejected by facts until a sound basis for decision is available. High on the list of cost effective tools for evaluation is the use of a geostatistically derived sampling program that provides a highly accurate ore reserve estimate for economic evaluation. When a predetermined sample of data from the drilling program and bench-scale or pilot-plant tests are received, a detailed feasibility study may be started. This study can involve design of the mine,

Jan 10, 1980

By S. M. Moore

Each year more than 400 coal miners are injured (fatally and nonfatally) by rock falling from between or around roof supports. Many of these injuries can be prevented by the installation of roof screen. However, many coal mines are reluctant to use roof screen because of the added cost. The goal of this study was to determine the potential savings in workers' compensation (W C) premiums that can be achieved due to a reduction in rock fall injuries after roof screening. The WC rate-setting methods utilized by Illinois and Kentucky were investigated in this study. Using data obtained from the Mine Safety and Health Administration, national and state WC bodies and individual insurance companies (e.g., average cost per injury, loss cost rate, number of injuries per year, number of injuries preventable each year with roof screening), baseline mines (representing two mine sizes: 67 and 150 employees) were constructed with realistic ranges for estimates of injuries and WC premium costs. Using each state's actual WC rate-setting formulas, a sensitivity analysis was conducted to determine the total savings in WC costs after a three-year period. Annual savings in WC premiums ranged from $41,000 to $326,000 for the 67-person mine, and $96,000 to $843,000 for the 150-person mine. An economic analysis of the cost of a roof screening program at a 67-person mine was also conducted. The annual cost of a roof screening program here was estimated at $240,000. At this mine, the reduction in WC premiums alone could pay for the entire screening program.

Jan 1, 2010

By Gary J. Fletcher

Mining and processing activities which are proposed on private land, state leases, or unpatented mining claims are governed by numerous local, state, and federal laws which identify the procedures and conditions which must be met before resources can be developed. The respective government agencies responsible for the administration and enforcement of these laws have promulgated supporting regulations and guidelines, and have implemented certain permit and approval processes to ensure compliance. Each exploration project has a unique environ- mental setting and location which further dictates the types of air, water, hazardous waste, and wildlife laws and regulations which must be complied with before development commences. The environmental planning process should be the first step in the evaluation of existing company properties and the potential acquisition of other mineral properties. However. many company don't consider the environmental requirements for a project until the decision is made to develop the property for mining and processing. If a mining company wants to expedite the environmental planning process, it must first develop an in-house process for evaluating the project and determining the environmental approval procedures in the state where the project is located. The first stage of environmental planning involves general information which can set the overall company philosophy for development of projects.

Jan 1, 1987

There are many risks associated with the storage of nuclear or other toxic wastes. One of the major risks is the escape of material from the repository. No matter how well a storage facility is engineered, the potential escape of dangerous material must be studied. This kind of study will include some estimation of the "travel path" of the particles. The travel path of a radio-nuclide particle will depend on the geological and hydrological parameters of the surrounding rocks. These parameters must be estimated from a limited number of samples available within the study area. Any estimation will -of necessity -contain a certain amount of uncertainty or "estimation error". This uncertainty will be carried through to the analysis of potential movement of particles, so that the estimated travel path itself will be subject to some error. This paper discusses an approach which may lead to a quantification of the uncertainty on the predicted travel path.

Jan 1, 1989

By Dirk van Zyl

Pad construction costs can impact the overall economics of heap leach projects. Pad construction costs for single-and double-lined pads, using various designs, are listed for a typical small and large project. Double-lined pads are now more often required by regulatory agencies. Unless such designs reduce the risk of site specific contamination significantly, the extra costs cannot be justified from an economical viewpoint. Specific attention is given to the short project life (typically five years) of heap leach projects. A few numerical examples are presented to demonstrate the overall economic impacts of these costs on economic parameters.

Jan 1, 1990

By Michael Michaylov, Elana Vlasseva

This paper presents a method for three-phase foam preparation recipe optimization. The pressurized foam is injected into porous media of gob area for prevention and fighting of SPONCOM fires. The method includes laboratory experiments for main foam properties as well as mathematical optimization procedure. Optimization criteria are formulated reflecting foam application purposes. The influence of solid phase on foam heat stability is shown. Results from optimization procedure for four foam agents by varying fly ash consistency of foam are presented. Theoretical basis for original construction of foam generator, specially constructed for of three-phase foam generation, is set u

Jan 1, 1997

By C. M. Sliepcevich

This paper is a brief status summary of investigations by the authors over the past decade to develop a continuous process for recovering' high purity metal powder from pregnant solutions by gaseous reduction at elevated temperatures and pressures. Although these studies included extraction of other metals such as nickel, silver, and gold, this presentation will be confined to the hydrogen reduction of acidic and ammoniacal solutions of copper. The continuous hydrogen reduction process (CHR) described herein enjoys the environmental advantages of other hydrometallurgical processes but, in addition, provides a substantial benefit in fuel economy over competing processes. As was recognized by Schaufelberger in 1956, for a given amount of fuel a continuous hydrogen reduction process has the potential for producing four to six times as much metal as an electrolysis process (1). Although hydrogen reduction of metal salt solutions has been known for more than a century, extensive development work leading to commercialization was not initiated until the 1950's. Since then, commercial applications relative to other extractive techniques have been minor and have been confined to batch or to continuous, completely-mixed autoclaves. By contrast, the process described herein utilizes a continuous, tubular reactor which is operated in modified plug flow so that only limited and localized backmixing occurs. Thus, gradients in concentration, temperature, and pressure exist over the length of the reactor, the presence of which can be utilized to advantage for achieving high conversions and product quality (2, 3).

Jan 1, 1975

By C. R. Landis

The Wyoming bentonite industry finished 2005 with strong growth. For most of the markets, demand exceeded supply. The industry continues to be heartened by the strength of its longtime markets, oilfield and iron ore pelletizing markets. But overall, all of the major markets enjoyed good to excellent commercial conditions. Growth at the macroscale was fueled by the continued strong domestic economy, by the exchange rate of the U.S. dollar in global markets and by strong worldwide global demand. As result, two new greenfield operations are in the early stage of development in the Wyoming region for the first time in more than two decades.

Jan 1, 2006

By B. E. Penrod

The main constituents of flat glass are the eight commonest elements of the earth's crust. Five of these, silicon, sodium, calcium, magnesium and oxygen are essential. Two more, Aluminum and potassium have beneficial properties. For colorless glasses iron is undesirable, in standard clear glasses a small amount of iron is tolerable, while for most tinted glasses iron is essential. These elements are present in glass as oxides and because they are so common there is no foreseeable resource shortage. The availability of supplies of materials at particular sites at prices which enable a glass manufacturer to be competitive may be another matter. In this paper it is intended to provide a historical perspective to the current situation, to contrast some of the traditional North American and European practices, and to progressively review some of the driving forces for future change and to attempt to assess their effects upon both raw material supplier and consumer.

Jan 1, 1994

By Tim Q. Haldane

The ability to efficiently process lowgrade ores has allowed the Gold Fields Mesquite Mine in Imperial County, CA to expand from a 2.1 Mt/a (2.3 million stpy) rate in 1986 to its present 7.3 Mt/ a (8 million stpy) processing rate. Increased tonnage demands led to the 1989 construction and startup of a dump leach pad to supplement the existing heap leach operation. This resulted in an excellent opportunity to compare the two processes at the same operation. Additional operating costs associated with the crushed ore heaps are justified through enhanced recoveries, even at very low ore grades. Gold Fields' Mesquite Mine is a gold heap leach facility located about 55 km (35 miles) east of Brawley in southeastern California. Five open-pit mines will be developed over the projected life of the property, covering a total area extending to a maximum of 5.5 km (3.4 miles) to the east and west, and 2.4 kin (1.5 miles) to the north and south. Mesquite will process 7.3 Mt (8 million st) of ore and produce more than 6.2 t (200 000 oz) of gold in 1990.

Jan 1, 1990

By J. K. Szymanski, Val Srajer

In this decade mining companies in western Canada have searched for reliable and inexpensive ways to improve mine productivity. Truck dispatching systems, equipment vital sign monitoring and sensing, vehicle guidance systems, have all been considered. In this paper the off -highway vehicle monitoring systems used or planned to be installed at surface coal mines in western Canada are described. The monitoring systems are divided according to their function and application; installation and testing procedures are described, as well as the economic benefits to the mining operation.

Jan 1, 1989

By Andrew S. Lain

Before you begin mining aggregates in Oklahoma, you must first look at the market and ask these questions: (1) Is there a need for additional aggregate production? (2) Can we produce the aggregate efficiently enough to compete? (3) Is the deposit close enough to the market? If you can answer "yes" to each of these three questions, then you are ready to start the process for mining aggregates in Oklahoma. The first consideration to be made is whether the aggregates produced will need to meet state specifications. If you do not want to meet state durability standards, there are numerous formations you can mine and produce aggregates. We will deal only with the formations that will meet state durability standards. These formations are located in the southern half of Oklahoma and in the Tulsa area. Some of the formations that contain limestone, dolomite, and sandstone that will meet state durability tests are West Springs Creek, Kindblade, McKenzie Hill, Butterly-Royer, and Rush Springs Formations. Granite and rhyolite also are found in Oklahoma and can be used as construction aggregates. Once an area has been identified as having durable material, and drilling has verified its properties, a permit must be secured from the Oklahoma Department of Mines, Oklahoma Department of Environmental Quality, and any other applicable agency before construction of a plant occurs. There are many different brands of crushers available, but all work on one of two crushing principles-either compression breakage or impact breakage. Each type has its application in different industrial-mineral types and the desired end product. A typical small crushing plant would start with a jaw crusher for primary reduction, and then employ one standard cone and one shorthead cone for secondary reduction. One grizzly would be in the circuit with one finished-product screen and three to four finished-product stackers. Natural sands and gravels are found in rivers and old river channels. These too need to be tested to see if spec product can be produced. All of our sand operations have very little gravel; thus, we do not process the gravel. The sand is processed through classifying tanks for gradation.

Jan 1, 1999

By J. Wes Blakely

In the mid-1950s the importation of foreign oil began to encroach on traditional coal markets such as railroad steam engine fuel, home heating, electrical generating plants, and others. Many of the smaller coal companies with substantial coal reserves subsequently found that they could no longer continue to mine economically and merged in various ways with larger established coal mining concerns. As the seats of top management and authority were removed from the mines to large metro centers such as New York, Pittsburgh, and Chicago, the more personal relationship between mine workers and management that had existed prior to these mergers began to be eroded and replaced by " remote control " mine management. The disappearance of this face-to-face contact of upper management with mine employees tended to create barriers blocking simple effective communications between coal mine management and labor. In examining the human relations aspects of the coal mining industry, many elements, some concerned with work and others not, have depicted the industry as almost devoid of good applied human relations and communications practices, and, in truth, little has been done to alleviate this situation. In past years many coal producing companies, with the exception of one of the largest, failed to adequately define the term "communications" as it applied to their companies, whether internally or externally. Internally many still place heavy reliance on written communications such as company-wide newspapers to do the job of communicating with their employees which they feel ought to be done. One company puts an inordinate belief in its company "newspaper" as the primary instrument to stimulate its work force into increasing productivity. Primarily aimed at the workers, who greatly outnumber the salaried administrative people, this publication mainly documents the fortunes of individual mine workers who are felt to have achieved something with their lives, e.g., a mine worker who had managed to put four children through universities, the philosophy behind this being to inspire other workers to achieve worth- while goals.

Jan 1, 1981

By A. D. Davis

Limestone-based material is effective for reducing arsenic concentrations below the current limit of 10 parts per billion for drinking water, typically resulting in final concentrations of about 4 to 6 ppb. However, in laboratory and field testing, further reductions to the 1 ppb range are difficult to achieve with limestone unless other material such as iron is added. The removal mechanism with untreated limestone appears to be the formation of a low-solubility precipitate of hydrated calcium arsenate, in the form of arsenate-apatite. Likely reactions and thermodynamic data indicate a theoretical removal limit of about 2 to 4 ppb for arsenic using raw limestone. Limestone also can reduce concentrations of cadmium and lead below 1 ppb in water, resulting in >99% removal efficiency. Thermodynamic constraints appear to be favorable for reactions involving the formation of otavite during cadmium removal and the formation of hydrocerussite during lead removal.

Feb 27, 2013

By L. J. Jansen

Techniques utilized to incorporate geological data in computer modeling and ore reserve estimation have undergone considerable evolution during the past fifteen years. Computer analysis and evaluation of two precious metal deposits are presented as examples of innovative computer techniques developed at Asarco. The first is a gold deposit occurring in a steeply dipping Pre-Cambrian greenstone sequence. The second is a manto-like manganiferous silver deposit occurring in a relatively flat sequence of Late-Paleozoic sediments. In both deposits, four sub-horizontal zones of geological influence are evaluated.

Jan 1, 1985

By Y. Breau, F. Robichaud

The Expert System implemented at the East-Malartic mill controls a copper flotation circuit while taking into account the profitability of the operation. Treating a copper gold ore, the flow sheet integrates a flotation step followed by cyanide leach circuit. The Expert System calculates the actual net smelter revenue of the flotation circuit, accounts for the operating cost of the cyanidation circuit and defines optimal metallurgical operating targets to optimize the overall economics. To be realistic, probability factors and circuit diagnostic analysis are integrated in the operating target selection. The Expert System has proved to be successful, robust and flexible. It resulted in a copper concentrate grade increase of 1% while maintaining recovery. The use of the expert system also gives plant personnel good training procedures and promotes interaction with mill operator.

Jan 1, 2002

By Maurus Seet Hong Hua

Introduction Coal has always been China's predominant energy resource. The country ranks among the three richest countries in coal reserves in the world, next to the US and the Soviet Union. According to China's Ministry of Coal Industry (MCI), coal accounted for about 72% of the total national energy consumption. Despite efforts to increase the output of oil and hydropower, coal is predicted to remain dominant on the energy scene by increasing its share to 77% by the turn of the century. To match the rapid growth in the agricultural and industrial sectors, MCI has targeted the coal industry to double coal output from 600 Mt/a (660 million stpy) in 1981 to 1.2 Gt/a (1.3 billion stpy) by the year 2000. How is this goal to be achieved? According to MCI, it will be accomplished by: • building new underground and surface mines with a total output of 400 Mt/a (440 million stpy); • increasing the output of existing state-controlled mines from the present 344 Mt/a (368 million stpy) to 400 Mt/a (440 million stpy); and • developing and increasing the output of small, local mines run by province, county, and production brigade from the present 276 Mt/a (304 million stpy) to 400 Mt/a (440 million stpy). Building new underground and surface mines New underground coal mines will be developed in areas where the coal industry has already made headway and infrastructures currently exist. This is to optimize hardpressed capital spending on investment. Ten existing coal production bases were selected in nine different provinces that met these requirements. The underground mines scheduled to be constructed in stages at he existing coal production bases will have a total output of 200 Mt/a (220 million stpy) by the end of the century. Regarding surface mines, four mines in the Inner Mongolia Autonomous Region and one in Shanxi province have been earmarked for construction during the same period. By the year 2000, these surface mines are expected to produce 200 Mt/a (220 million stpy). Foreign equipment, machinery, and surface mine stripping technology were all involved in different degrees in the development of the five new surface mines. Some have signed joint venture agreements. Occidental Petroleum Corp. is in a joint venture with China in developing Ping-shou's 15 Mt/a (16.5 million stpy) Antaibao No. 1 open-pit. The Shentou power station, situated nearby, is anticipated to consume 3.2 Mt/a (3.5 million stpy) of the coal it produces. Some is designated for export. Increasing output There are 554 state-controlled mines that have been in operation since before 1980. They produce 344 Mt/a (379 million stpy). To increase capacity, MCI has laid out some guidelines. • Coal prospecting near existing mines must be given top priority and intensified so that workable reserves can be increased. This would lengthen the mines' useful life. • Many mines and slopes that were constructed during the 1950s are very small and densely populated. These small mines and slopes are generally very short along the strike. As a result, coal faces and levels require frequent

Jan 3, 1986

By N. D. Jagger

In order to maximize the benefits obtained from flocculating agents when used as settling aids in high rate and conventional thickeners, it is often necessary to dilute the thickener feed prior to flocculant addition. In some cases, no flocculation at all is possible unless dilution water is used. The most common method of diluting thickener feed has been to recirculate some of the thickener overflow by means of a centrifugal pumping system. This represents a significant capital and operating cost. Supaflo Technologies of Australia has developed and patented an internal recirculation method known as Auto Dilution (or "Autodil") which is based on the principle that an hydraulic head differential exists between the inside and outside of the feedwell because of the higher S. G. of the pulp inside the feedwell, By installing non-return ports in the feedwell wall at the appropriate level, supernatant solution flows into the feedwell at a calculated rate and dilutes the feed without any need for external recirculation of overflow.

Jan 1, 1993

By Ronald E. Yarbrough, Theodore L. Triplett, Larry R. Powell

The Bureau of Mines, in cooperation with the Illinois Mine Subsidence Insurance Fund, is monitoring the response of two foundations to ground movements induced by subsidence from a high-extraction retreat room-and-pillar operation in southern Illinois. The objective of this monitoring program is to study the inter- action between the ground surface and a structure during a subsidence event. Data from such a study should enhance the understanding of the mechanisms that produce structural damage and aid in the design of structures that resist such damage. This paper describes the monitoring instrumentation and techniques as they relate to the mining and site conditions. The capability of a tiltmeter to detect and follow the tilt of the foundations caused by the mining subsidence sequence is demonstrated. Using data from this tiltmeter, the development of curvature in the foundations as they conformed to the displaced ground surface is shown. This curvature is rep- resented by differences in tilt at various points on the foundations, indicating a change in tilt over a horizontal distance. Also, even though subsidence damage has not been fully analyzed, preliminary observations of the cracks that formed in the foundations are reported. These cracks resulted in the separation of one footing into distinct pieces; therefore, their effect on the tilt readings is cited.

Jan 1, 1986