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By James R. Arnold

Gold Fields Mining Corporation started processing ore from it's Chimney Creek operation in northern Nevada in November, 1987. Since that time production has averaged about 200,000 ounces per year from the milling and dump leaching circuits combined. The events that led up to commissioning of the plant started in January of 1985 when the Gold Fields exploration team drilled their first hole in an area now known as Discovery Hill. The major orebody was located later in the year in what is currently the major focus of activity, the North Pit. Subsequent drilling since plant startup has found another 14 million tons of ore two miles south of the original orebody. This South Pit orebody is currently being stripped and metallurgical testing is underway. Engineering Engineering on the Chimney Creek plant started in earnest in May, 1986. Davy McKee Corporation from San Ramon, California, did both the engineering and the construction management. Before engineering began the entire senior staff of the Plant Department was hired and assigned to the project. Senior staff included the Plant Superintendent, Plant General Foreman, Maintenance General Foreman and Chief Metallurgist. Gold Fields does not employ an internal central engineering staff to design their plants. We feel that the people who design the plant should be the ones who will be required to run it once it has been commissioned. This philosophy affords a continuous accountability from start of design through commissioning and operations. All four of the senior staff spent the most critical phase of the engineering stage at Davy McKee, so the plant is truly a reflection of all four disciplines. In bringing on the Maintenance General Foreman from the start, there was a focus placed on ease of maintaining the plant. Another philosophy that was adopted from the start was that the plant be easy to work in and maintain for both operators and maintenance personnel. Numerous design criteria were given to Davy McKee to ensure this. For example, we required that every piece of equipment could be reached easily with a crane or fork lift. All conveyors were required to have walkways on both sides for ease of maintenance and a minimum of 30 inches of clearance under them for ease of cleanup. Visibility for operators was considered very important and the control rooms and general plant layout were designed with this in mind. A list of about 100 general rules were given to Davy McKee during the early layout meetings and these were held as the general design criteria throughout engineering and construction. While engineering was progressing in San Ramon, California, dump leach test work was being done at the site. Three 6 foot diameter fiberglass columns were constructed and filled to a 20 foot height with low grade ore. Leaching characteristics were determined and the dump leach design was based on information collected from these columns. Construction The major contractors on the project were The Industrial Company for the bulk of the piping and structural, EMKO on the electrical/ instrumentation and Hunewill for most of the earth work and leach pad construction. All plant operating and maintenance personnel were employed eight weeks before startup for intensive training. Instructors were Gold Fields personnel, including foremen, and Davy McKee engineers. On occasion, selected suppliers representatives were brought in to discuss major pieces of equipment. Project completion was targeted for January, 1988 at a projected cost of 78.9 million dollars. Actual startup was about 1 1/2 months ahead of schedule and slightly under budget. Full design capacity was achieved the first full month of operation. Crushing Run of mine ore is delivered to the crusher and dumped into a 90 ton hopper which is topped with a 30" X 30" opening stationary grizzly. Ore is fed to a 50" X 60" Telsmith jaw crusher with a 5' wide apron feeder. The closed size setting of the

Jan 1, 1989

By Gerald L. Dollinger, Joseph A. Roby, David Krauter, Kenneth Deering

Three high performance TBM's equipped with large diameter (483mm) disc cutters are currently operating in Norway. This paper summarizes the design philosophy, field performance and ongoing technical development of these cutters. Included are discussions of the early problems encountered with their usage and the solutions to these problems that have been developed. Also included are discussions of the penetration rates and cutter usages observed. From this data it is concluded that high performance TBM's with large diameter cutters can produce significant improvements in both overall performance and in cutter costs under hard rock conditions.

Jan 1, 1991

By Stacey Leichliter

The Cripple Creek and Victor (CC&V) Gold Mine (Cresson Project) (Fig. 1) is undergoing an expansion to extend production to the year 2025. This expansion involves building a high-grade ore mill, another valley leach facility (VLF) for heap leach operations and expanding the overburden storage areas. The current operating pits are progressing downward from the oxide ore into a more sulfide and telluride-rich orebody. There is still oxide ore present in the current pits and planned pits not yet mined. There is an increased need for two recovery processes for these two different types of ore. The key component to this expansion is the high-grade ore mill, which has gravity, flotation and carbon-in-pulp (CIP) circuits. The mill will be the main recovery process for the higher grade, more sulfide/telluride-rich ore. This ore type does not recover well on the heap leach pad due to its refractory nature. Geometallurgy is vital for ore characterization for the two recovery methods. Geometallurgy helps develop indices that are used to predict parameters that influence overall recovery and production, such as hardness, crushability, grindability, pH fluctuations, gravity (coarse) gold, flotability and cyanidability. Using geology and mineralogy along with other analytical data, geometallurgical models are constructed and applied to the resource block model for proper planning and extraction of the gold. Geometallurgy aims to analyze the variability in the different responses to the parameters to help reduce risk (costs) and optimize recovery (profit).

Jan 1, 2013

By Elham Najafi, Sina Ghassa, Ata Akcil, Hadi Abdollahi, Sandeep Panda, Zohreh Boroumand

Bioleaching is an environmental friendly process that has gained much interest for the production of metals from metal-bearing wastes or materials. The process decreases carbon footprint by reducing consumption of fossil fuels. Iron is a key factor in acidophilic iron-oxidizing bacteria’s activity, which is used extensively in the bioleaching of sulfide minerals. In the present study, the effect of different iron sources is investigated on sphalerite (ZnS) bioleaching. For this purpose, the effects of FeSO4  .7H2O, Fe2(SO4  )3 and FeS2 (pyrite) were studied on bacterial activity, and zinc (Zn), lead (Pb), cadmium (Cd) and arsenic (As) dissolutions were monitored from a ZnS concentrate. Under optimum conditions, the dissolutions of Zn, Pb, Cd and As were found to be 39.8, 0.1. 0.03 and 10 percent, respectively, in 25 days.

By D. I. Hoyer

A preliminary model has been developed for autogenous pebble milling using information obtained from studies on ball milling and SAG milling. The model treats the breakage as the weighted sum of first-order breakage of smaller particles by tumbling pebbles, non-first order breakage of larger particles which are too large to be nipped properly by pebbles, autogenouS fracture and chipping of larger lumps to form pebbles, and autogenous fracture and abrasion of pebbles. The model includes the effects of residence time distribution, classification through the exit grate, and a mass transfer relation which describes the accumulation of fine material in the mill. Example simulations are given, based on breakage parameters determined from batch grinding tests in laboratory mills. fracture breakage and abrasion. In the development of these preliminary mass balance equations it will be assumed that breakage by fracture is first-order, but this assumption will be modified later in the paper. It will also be assumed that the residence time distribution of a long autogenous mill can be described by an equivalent series of m fully-mixed mills, with a classification action imposed on the mill contents by the discharge grate. Size distributions are expressed as a v2 geometric series, numbered 1 for the top size down to n for the fines, or "sink" interval. If the holdup in the mill is W then the rate of breakage of material in size interval i is given by SiwiW, where wi is the fraction of material in size interval i, and Si is -the overall specific breakage rate of size i material (fraction per unit time).

Jan 1, 1985

By J. F. T. Agapito

The load carrying capacity of oil shale pillars excavated by conventional blasting, presplit blasting, and mechanical mining is evaluated. The study was based on a comparison of in-situ vertical stresses and fractures obtained from overcoring horizontal holes in the Colony Mine, Piceance Creek Basin, Colorado. Results indicate that conventional blasting causes a zone of damage approximately 3 m (10 ft) thick with low stress distributions. Presplit blasting reduces damage significantly, and increases the load carrying capacity in the 3 m (10 ft) thick zone by 5.93 MPa (860 psi). Mechanical mining causes little or no rock damage, and an increase of 9.83 MPa (1425 psi) in strength in the same 3 m (10 ft) thick zone. An example of pillar design is given showing that the use of presplit blasting and mechanical mining techniques can increase the extraction ratio by at least three and five percent, respectively, as compared to conventional blasting. It is speculated that comparable increases in extraction should also occur due to increases in span dimensions.

Jan 1, 1984

By A. M. Radigan, W. G. Prast

M.S. Azun The authors' paper did not explain the facts and reasons why state companies are established and what their role is in international industrial mineral trading. Also, I do not agree with the conclusion implying that the main goal for state companies is to capitilize natural resources. Almost all state companies are founded by certain laws and their activities are arranged by state regulations. Their only aim is to operate mineral deposits for their people and to protect the rights of the people. Although some ore deposits, such as nonstrategic or small, may be exploited by privately owned companies, the state has the right to control the operation and production. Activities of state companies may or may not be widened because of the character of the deposits and the importance of the mineral market involved. For some countries, although governments may occasionally change hands, the policy of the mineral trading system is not affected by this change. There is no doubt that any government desires to make more earnings to increase GNP, when it is involved in operating and trading mines. It wants to produce and sell the finished products, instead of unprocessed ones, if possible. When it is known that some mineral deposits are relatively rare, such as Turkish boron deposits, the government can nationalize the mines to control production and affect the market. If there is an abundance of a certain mineral in the market, the government can cut production and set a floor price, such as Canadian potash. Also, when production of a specific mineral is unique, such as Turkish chromite, the price of such mineral may be set by correspondant government. One may add that if some governments with their state companies produce a certain mineral in a larger amount, they may decide to establish a cartel to protect their production and price. These are the facts followed by government-owned state companies and partially government-owned companies. The reason being charge of many deposits by the state companies is always the same: "protect" the mineral rights of the people.

Jan 2, 1984

By S. P. Singh

Drifts are the nerve centre of underground mining. They provide essential communications between primary openings and production areas. In view of their strategic importance in the overall safety, economy and productivity of mines, an empirical approach for blast design during drifting has been proposed in this paper. The approach was developed with the objective of minimum blast damage and provides computerized blasthole patterns for drifting operations. The drift blasting practices and problems in Canadian mines have also been reviewed in this paper.

Jan 1, 1991

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

The National Mining Hall of Fame and Museum will hold its Ninth Annual Induction Banquet Sept. 8, 1996, at the Las Vegas Hilton Hotel. Six mining greats, two of them living, will be enshrined at the event. They will join 126 other mining legends previously honored by the hall of fame. The keynote speaker will be William Perry Pendley, president and chief legal officer of Mountain States Legal Foundation in Denver, CO. Jeffrey Zelms, president and chief executive officer of The Doe Run Co., will be master of ceremonies. Richard Swayne, regional director USA for Boart Longyear Co. of Salt Lake City, UT, will introduce the speakers. Thomas Falkie, president of Berwind Natural Resources Corp. and chairman of the Mining Hall of Fame’s board of governors, will enshrine the inductees.

Jan 1, 1996

By Sah Rameshwar, T. Umadevi, K. S. SRIDHARA

In the magnetite iron ore pelletization process, oxidation of magnetite followed by sintering of the oxidized magnetite (hematite) is desirable. Optimum preheating time & temperature and roasting time & temperature is required to get the desired properties of the pellets with magnetite, hematite, and hematite–magnetite blend. In order to utilize the magnetite resources in a current induration furnace, which is designed for hematite resources, detailed pelletization studies have been carried out to optimize the firing cycle for magnetite concentrate as well as magnetite with hematite concentrate. Under optimum conditions, such as preheating temperature 1000–1150 °C, preheating time 10 min, roasting temperature 1250 °C and roasting time 7.5 min, the cold compression strength (CCS) of magnetite roasted pellets was 325 kg/p, and this was due to recrystallization of secondary hematite particles, and development of the strong slag bond between primary and secondary hematite particles. The strength of hematite concentrate pellets was 260 kg/p. From laboratory studies, it was found that without disturbing the induration furnace firing cycle, which is designed for hematite ore ~5%, magnetite concentrate can be used along with hematite concentrate in pellet blend and the strength of the pellets was 270 kg/p. As the magnetite concentrate increases in the blend beyond 5%, the preheating zone residence time should be increased or a supply of extra oxygen is required. Laboratory as well as plant investigation has shown that the addition of magnetite to the hematite mix blend improved the strength of the pellets compared to hematite pellet alone.

Oct 26, 2020

By Linda Frederick

In July 1997, Krupp Canada obtained the contract to design and supply the conveyor system for Chile's Los Pelambres copper mine expansion project. Progress on the overland conveyor system is currently on schedule. It is a challenging task to convey copper ore from an open-pit mine located on a mountain site 3,000 m (9,840 ft) above sea level down 1,300 m (4,265 ft) to the processing plant at the valley floor below. The Los Pelambres conveyor system moves copper ore at a rate of 8.7 ktlh (9,600 stph) and at a speed of 6 ml sec (1,180 ftlmin) for 12,750 m (41,830 ft). The distance is divided in three conveyors, each 1,800 mm (71 in.) wide. The largest conveyor is 6 km (3.7 miles) long. To protect against avalanches and rockslides, the conveyors run through a 12-km- (7.4-mile-) long tunnel system. The lowest of the three conveyors is equipped with a shuttling head end. With this, the conveyor discharge point can be moved back and forth by 100 m (330 ft), allowing it to build up a longitudinal stockpile at its end. To meet the extreme design parameters, the limits of conveyor design had to be pushed to record-setting marks. For instance, the ST-7800 steel cord conveyor belt is the strongest belt ever installed in a conveyor system. A total drive power of 25 MW (33,535 hp), consisting of 10 2.5-MW (3,352-hp) drives, is included in the design plans. In loaded condition, the electric motors act as generators and feed electric energy back into the power grid. The motors are controlled by variable frequency inverters that provide an infinite adjustment of motor speed. This technology allows starting and stop- ping the conveyors precisely along predetermined acceleration and deceleration ramps. This is done so harmful belt jerking and stress waves can be avoided.

Jan 1, 1999

By M. D. Lawton

Anglo-Rouyn Mines Limited, managed by Rio Algom Mines Limited is a subsidiary of the British-based Rio Tinto-Zinc Corporation Limited. This mining operation is situated in Northern Saskatchewan, 250 miles north of Saskatoon and represents the first base-metal mine of any importance served by this relatively new mining province. The outcrop of Copper-bearing Chalcopyrite was first discovered by prospectors in 1915, but was not mined until 1965 due to the absence of any form of road into the area prior to this latter date. The mine, mill and concentrator were designed to handle 900 tons per day of comparatively hard, abrasive ore containing chalcopyrite with traces of gold and silver. The flow sheet, Figure 1, is, we believe, elementary, designed with low cost in mind and utilises much old equipment from closed¬-down mines. Due to some difficulty in attaining the designed grinding capacity, changes were made in the crusher circuit. This, unfortunately, lowered the crushing rate too much. A series of changes have taken place to re-establish the original crusher capacity of better than 100 tons per hour. In the quest for a better recovery certain modifications have been tested in the concentrator circuit. These steps are discussed in minor detail.

Jan 1, 1970

By Changwoo Lee

Under drastically deteriorated situations, diesel equipment was introduced to some of local coal mines, aiming at higher productivity and better safety. To accommodate various diesel equipment in conventionally developed mines, mining system itself had to be modified; much larger trackless haulage ways were excavated. Possible health hazards of diesel not taken into account at the beginning become a serious concern and effective control measures are being searched for. The purpose of this paper is to study the diffusion characteristics of diesel exhaust in local coal mines. One of the parameters affecting dispersion of diesel contaminants is the coefficient of turbulent diffusion. Since CO2 is known to be closely correlated with other contaminants such as CO, NO, NQ, SO2 and RCD, it was chosen as a tracer gas in a series of dispersion experiments. A large diesel passage as well as a conventional track haulage way were the sites for the experiments. Rectangular dispersion pulses were generated for 30 ~60 seconds and CO2 concentrations were recorded at several locations 50~190 m downwind. The diffusion coefficients calculated graphically vary between 0.10~0.48 m2/s at both haulage ways. The results are analyzed to find any correlation with the air velocity and the distance from the disperser. Skobunov's empirical formula is applied to the experimental data for comparison and the relationship between Reynolds number and Ex/Dp/sci0.4 Sc1…

Jan 1, 1995

By Roland Arnold, Richard Gradnik, Martin Zeindl

This paper presents the details of the Kramer tunnel project in the Federal State of Bavaria, Germany. This road tunnel, which has been under construction since December 2019, is the key component of the western bypass of the town of GarmischPartenkirchen. Once completed, it will relieve the town’s central district from enormous volumes of traffic. The contractor is the joint venture named ARGE Kramertunnel consisting of BeMo Tunnelling and Subterra. The whole project will be completed and handed over to the project owner, Staatliches Bauamt Weilheim, in 2023. The opening of the entire bypass section including the tunnel to traffic is planned for 2024. The tunnel, with a total length of 3,609 m (2.24 miles) and an estimated cost of EUR 178 million (incl. VAT), is designed as a single-tube, double-lane structure with one traffic lane for each direction of travel. The safety issue that exists for single-tube tunnels is solved by a parallel escape tunnel passable for vehicles. All tunnels and ducts are excavated according to the principles of the New Austrian Tunnelling Method (NATM). In order to reduce the geological risk for the owner, the escape tunnel was supposed to be completed before the design process for the main tunnel ever began. The exploratory tunnel was awarded to a competitor with an separate contract.

Jun 13, 2021

By James R. Jones

The Surface Mining Control & Reclamation Act is a complex piece of legislation signed into law on August 3, 1977. It is the culmination of more than six years of debate by the Congress over the need for a national regulation of surface mining as opposed to the prior concept of regulation by each concerned state. It departs from the more normal type of law in that it includes very specific requirements, limitations and performance standards. In its procedural aspects, it is somewhat similar to the Clean Air Act and the Water Pollution Control Act in that it places primary responsibility at the state level, provided the state meets minimum national requirements. At the time of writing this paper, in late December 1978, the Interim Regulatory Program has been in effect for seven months. The proposed regulations for the Permanent Program, the draft Environmental Impact Statement, and the draft Regulatory (Economic) Analysis ware available for eight weeks before the close of the comment period on November 27. We are now awaiting issuance of the final versions of these documents. The states in which coal is mined, for the most part, have made sere revision to their state laws and are in the process of revising their regulations, or have just completed the revision, to comply with the Initial Regulatory Procedures. They are now faced with another new major effort to analyze and plan for compliance with the Permanent Regulatory Program, which is expected to be promulgated by the Office of Surface Mining of the Department of Interior by the time this paper is presented.

Jan 1, 1979

Iran possesses very large copper resources, estimated to contain around 4-5% of the world's known copper inventory. There are several small private sector copper mining operating in the country, but Iran's copper industry is dominated by the state-owned National Iranian Copper Industries Company, which operates the world-class Sar-Cheshmeh open-pit Mine. This mine was developed in 1970s before the 1979 Islamic Revelation by the Atlantic Richfield Company (ARCO), the former Anaconda Copper Mining Company. Current Iran?s copper cathode production is about 250,000 mtpa and recently it is targeted to reach to 700.000 t by 2014. The required finance for this target is estimated US $2.25 -b, i.e. US $5000 for each tonne capacity. The copper content of the mineable reserves of the country is estimated about 19 Mt. It is not unlikely this amount increases in close future. Currently, almost 30 projects consist of mine, concentrator, smelter, refinery, acid plant, leaching, bio-leaching are underway. These projects are a golden opportunity for the local and foreign companies, but the recent sanctions are very challenging that all studied in this paper.

Jan 1, 2012

By J. O. Costello

Marble is a preferred surfacing material in up-scale buildings. Its use increased in the 1870's with rising national wealth and declined in the 1950's when synthetic materials for these applications were developed. Natural marble is now limited to high-end domestic and commercial structures. Cultured marble is a paste of white marble dust and polyester resin cured in molds yielding fixtures of specific finished dimensions. Dyes incorporated at different stages in the mixing cycle mimic shades and veining of natural marble. This paper discusses the filler requirements for cultured marble production and reviews new techniques to cut and finish natural marble.

Jan 1, 1999

By LeEtta M. Shaffner, John R. Marks

The Homestake Gold Mine in Lead, South Dakota, commenced operations in 1876. As is the case with old, deep, continuously developing mines, a ventilation improvement is periodically required to maintain acceptable underground environmental conditions. Recent historical improvements at Homestake include a 5.2m diameter air shaft driven in the 1960's and a 2.1 MWR (580 ton) chilled water plant installed in 1978. By 1983, it became apparent that yet another ventilation upgrade would be needed to keep pace with accelerated development in the deepest mining sections. A study was therefore undertaken to project ventilation requirements for the next ten years and to select the method(s) most suitable to meet those requirements. The study called for a two-phase approach in which air flow and air conditioning were carefully balanced. Phase I, the installation of a new 2240 kW surface fan and several underground circuit changes, was completed in 1986. This paper describes Phase 11: the planning, design, installation and initial performance of the air-conditioning portion of the upgrade.

Jan 1, 1989

By John Bley

White Pine Copper Company operates a mine in the Upper Peninsula of Michigan using a modified room-and-pillar system for extracting ore.1 Mine production averages 15, 500 tons per day. The terrain is predominantly level and the depth of cover varies from 500 to 800 feet over the present workings with depth increasing as mining progresses down the dip. The deposit is situated on a low angle plunging, anticlinal structure composed of sedimentary beds. Local terminology for the stratigraphic units which contain the ore horizons, named in ascending order, is as follows: lower sandstone, parting shale, upper sandstone and upper shale. The ore zones of copper enrichment are, contained in the parting and upper shales. The parting shale will vary; from 6. 5 to 9.0 feet thick; the upper sandstone from 2 to 10 feet; and the upper shale from 1. 5 to 6. 5 feet. Two variation of the room-and-pillar system are used to extract the ore depending on grade and local ground conditions. One system is called the parting shale method and recovers the parting shale only. This system requires a mining height of 8 1/2 feet to accommodate large-scale, high-capacity equipment and this working height is obtained by removing approximately 1 to 2 feet of the barren lower sandstone with the ore. Under the second system, locally termed full column, the mining height is about 14-1/2 feet and this system removes the parting shale, the upper sandstone and the lower mineralized zone, approximately 1-1/2 feet, of the upper shale at which point it is possible to maintain a competent back (Fig. 1).1

Jan 1, 1964