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GENERAL DESCRIPTION The Lucky Friday mine is located in Mullan, Sho-¬shone County, Idaho. The mining method is horizontal slice cut-and-fill (with timbering for support or un¬timbered) using hydraulic sand. Cemented sand fill at a 1:17 ratio is used in sill pours and at a 1:7 ratio for the final 152 mm (6 in.) capping in successive stope floor pours. Annual production with 100% cut-and-fill mining is 167 829 t (185,000 st). The average depth of mining is 1296 m (4250 ft) and the average travel time to the stope is 45 min. GENERAL ORE BODY REQUIREMENTS AND LIMITATIONS Size The ore body is 396 to 488 m (1300 to 1600 ft) long on strike, 1421 m (4660 ft) on dip, with an average width of 2.3 m (7.5 ft). Dip varies from vertical to1.2 rad (70°) Ground Conditions, Ore Value, and Production Requirements The ore body contains quite strong argentiferous galena and quartz. The hanging wall and footwall are strongly sheared and fractured. Ore value is $211/t ($192/st).

Jan 1, 1982

By Toshio Fujiwara, Sumikichi Ito, Masao Kitamura

The Tennohji-Benten Giant Trunk Sewer Project has been under construction since 1974 in the eastern part of Osaka, the second largest city in Japan. The entire project is divided into 7 blocks, some of which have already been completed. This 8.8-km sewer tunnel, being driven through a densely populated area, was planned to be constructed by the shield tunneling method. This paper described shield tunneling performances and ground behaviors during the construction of Blocks 2 and 3. An earth pressure shield (dia., 6,750 mm) was employed in Block 3 tunneling. The ground was generally soft and the cover over the tunnel varied from 13 m to only 4.5 m, so that a considerable amount of chemicals was injected to stabilize the ground. A hand-digging type shield (dia., 7,250 mm) was used in Block 2 tunneling under compressed air. For 85 m of the total length of 1.6 km, the soil at the face was extremely soft, and therefore, the ground freezing method was additionally employed.

Jan 1, 1981

By G. R. Luster

In most current practice, the methods that are employed in technical evaluations of cement raw materials are deterministic; i.e., decisions among alternative raw mixes and alternative plant designs are reached with the aid of only "average" compositions and "representative" samples of the available raw materials. Nevertheless, cement plants are sensitive to raw-material variability, and uniformly high-quality raw materials are not so abundant as they once were. Some simple examples will illustrate how geological techniques can be combined with geostatistical and operations-research approaches to customize mining and processing systems to deal with variable raw-material compositions.

Jan 1, 1987

By Meghan Murphy, Yiming Sun, Kush Chohan

DTX is a 1.3-mile-long rail extension being constructed by Transbay Joint Powers Authority to extend Caltrain rail service and future California High Speed Rail service to downtown San Francisco. It includes a 3,352-foot-long mined tunnel with a cross section varying from 50 to 60 feet wide and 43 feet high to accommodate two- and three-rail tracks. DTX will be excavated in mixed-face and Franciscan Formation with ground cover ranging from 40 to 85 feet. This paper discusses how mined tunnel design has evolved since the initial preliminary design phase over 10 years ago. The current design concept for tunnel construction is also discussed.

Jun 13, 2023

By A. Dale Wunderlich

In the past, most people have associated gold scams with the sale of non-existent gold mines, an undivided interest in unmined ore or the sale of gold-plated lead bars. These scams are still available to those who want to speculate. Now, though, the mining industry is plagued with a new type of con artist. Many of the new scams involve large, well established mining companies being victimized. Nearly all legitimate mining companies are in search of good mining prospects. This makes them susceptible to modern day con artists. Many professionals from the mining and petrochemical industries are out of work. Some of them have gotten involved with scams or activities that border on the criminal. Mining companies are losing millions of dollars each year to scams. Some of these scams involve venture-capital fraud. Some involve fraudulent mining proposals. And some involve unqualified individuals who are providing services by the precious metals industry. The author estimates that mining scams may be costing precious metals companies as much in dollar losses annually as employee theft. Employee theft is at an all time high, but so are gold scams. Since January of 1990, the au¬thor has been involved in gold theft investigations in which more than $1 million in gold product has been stolen by employees. In the past, most of the gold mine scam operators have concentrated on the general public, which is generally ignorant of basic mining procedures and practices. A scam artist would tell someone from your neighborhood that they have a wonderful underground mine. It produces 62.2 kg/t (2000 oz per st) of gold ore. Your neighbor might think that sounds like a very good investment. Those involved in the mining industry know better.

Jan 1, 1990

By C. L. Lin

A PC image-based on-line coarse particle size analyzer has been developed to measure particle size distributions under plant situations where overlapped particles are being transported on a moving belt conveyor. Although previous testing had shown satisfactory performance of this image-based system for separated particle size measurements (the non-overlapped case), it was necessary to modify original algorithms in order to solve the overlap problem and make the system suitable for plant operations. On-site testing has been conducted at a large copper concentrator in the southwestern U.S. for further investigation of the overlap problem.

Jan 1, 1995

By J. C. Harrison

Eldorado Gold Corporation of Vancouver, B.C. owns and operates three gold mines. The Sao Bento underground gold mine in Minas Gerais State, Brazil produced 105,907 ounces in 1997. The La Colorada and La Trinidad open pit, heap leach mines in Mexico produced over 83,000 ounces in 1997. With a deteriorating gold market plaguing the industry throughout 1997 Eldorado had to take critical measures at each mine to enhance gold production while lowering cash operating costs. Each mine had its own unique problems to confront. This case study will discuss three distinct courses of action taken at the three mine sites.

Jan 1, 1999

By J. C. Johnson

The problem of estimating pillar capacity in coal mines has motivated development of a variety of empirical equations. Most of these equations have arisen from experience and a very limited set of measurements that have, necessarily, been focused on particular regions or coal fields. Their applicability is often limited to a specific range of pillar sizes. This is of particular concern in the design of large gateroad pillars and small barrier pillars between panels. The result has been a variety of equations and equation coefficients that can calculate load estimates to size pillars. Inclusion of these equations in more sophisticated loading models, such as boundary element methods (e.g. LaModel and MULSIM) has been hampered by absence of a function that describes specific variation of coal strength within the pillar. A singular exception, to our knowledge, is a function corresponding to the Bieniawski pillar strength equation. Because of this, it is the only coal strength criteria inherently available in most boundary element models. This paper presents a general method for deriving local coal strength, as a function of distance from the pillar rib, for an arbitrary pillar strength equation. Integration of this function provides the strength of pillar regions, or cells, needed for boundary element models. The method is demonstrated for the Bieniawski, Maleki and Holland-Gaddy equations. The Maleki and Holland-Gaddy equations contrast strongly with Bieniawski as strengths are extrapolated to large pillars and barriers. This development provides a tool for incorporating any of the proposed empirical equations into a boundary element model, thereby allowing the analyst to choose the most appropriate equation for a particular region, coal seam and/or pillar size.

Feb 23, 2014

By Corey Vaughan

Unplanned shutdowns from abrasive wear part failure in crushers, chutes, and slurry pipe assets can cost millions in lost production and reactive maintenance. 2Censor patented sensor technology enables real time abrasive wear monitoring of mineral processing equipment, turning passive assets into smart, data driven components. Wireless sensors embedded in liners and pipework transmit wear data live to operators, allowing for predictive maintenance, safer scheduling, and optimized asset life. This paper will present global case studies showing reductions in downtime, increased throughput, and improved maintenance accuracy. The system is ready to retrofit, neutral to original equipment manufacturers, and proven across more than twelve countries in abrasive wear liners and slurry pipe applications.

Feb 22, 2026

By Verya Nasri, James Sullivan, Alex Varas

"INTRODUCTION Many major cities in the United States have a combined storm water and sanitary sewer network. Regular rainfall overwhelms the system capacity and results in millions of cubic meters of untreated sewage being dumped into local waterways. One legally mandated solution includes several kilometers of large diameter shallow or deep rock or soil tunnels, a pump station as well as associated collection sewers, diversion structures and drop shafts. In this paper, the basis for design of different system elements including the drop shafts and pump station is explained in detail. Common construction methods used for different type of shafts including tangential vortex and baffle plunge, and also pump station alternatives comprising cavern or various shaft configurations are discussed. DIFFERENT TYPES OF PUMP STATIONS The dewatering pump station serves as the heart of any deep CSO tunnel system and is critical to the goal of reducing CSOs by providing a controlled release of the stored tunnel volume to the wastewater treatment plant. As the major mechanical component of the project, the station will require the greatest attention by operations and maintenance staff. Designing a durable and easily operated pump station requires addressing some major challenges, including the following: • Longevity – equipment, materials of construction, and station environment • Controlling odors • Safety for operators and maintenance personnel • Easy access to equipment • Protection from hydraulic surges Location. Owners face a fundamental decision relative to the location of the pump station, which will affect how these challenges are addressed. The pump station can be built within the tunnel launch shaft or within its own dedicated shaft. This decision is driven by cost and schedule. Use of the tunnel launch shaft may provide owners cost saving opportunities by not having to construct a separate pump station shaft. However, this will likely extend the pump station construction as much as two years until the tunneling has been completed. Furthermore, delays to the tunneling operation would delay the pump station construction work, potentially leading to delay claims. For this reason, it has been more common to utilize a separate pump station shaft on recent CSO tunnel projects (Nasri et al. 2015)."

Jan 1, 2016

By M. Rodgers

Dow Water & Process Solutions (DW&PS) was approached by ASARCO Inc. to attempt to recover cobalt and copper from their copper solvent extraction (SX) raffinate. Cobalt is added to many copper electrowinning tankhouses to help to prevent lead electrode corrosion. With cobalt?s high price this can be a large expense. ASARCO has ore that contains a small amount of naturally occurring cobalt. Currently they have no way of capturing this high value metal from their leach or raffinate streams. DW&PS has some chelating resin technologies that should be able to help solve this problem.

Jan 1, 2010

By Harry M. Conger

Good afternoon, fellow members of the international mining community. I appreciate the opportunity to participate in this special three-day, international gathering, and to join with you in honoring one of my very good friends, Doug Fuerstenau. It couldn't be more fitting to have this kind of event to mark Doug's 60th birthday. You know, in addition to his faculty position at the University of California in Berkeley, Doug is a member of the Board of Directors of our Homestake Mining Company. So it is a double pleasure for me to help pay tribute to one of the outstanding academicians of the mining industry as well as a man with whom I work closely in running Homestake. I have been asked to talk about "The Future of Precious Metals," but I will concentrate my remarks on gold. Since the theme of this Symposium is "Challenges in Mineral Processing," what I'm going to talk about is a challenge that relates especially to a major problem faced by those of us who process ores to recover gold. I noted that in the Scope of this Symposium, it stated: "the mineral industry is currently facing many challenges to improve the economics, operating efficiencies and environmental concerns of the mineral processing system." I couldn't agree more with that statement. I think that a need exists for us to address this situation as it involves gold. And who better to consider this than the worldwide leaders of mineral processing research here assembled. I start with the premise that we need a new method for cyanide use or a chemical to replace sodium cyanide entirely. In the case of using cyanide differently, I see a continuing difficulty in getting general public acceptance regardless of how

Jan 1, 1989

By H. M. Breza

Utilization of Bucket Wheel Excavators and Overland Conveyor Systems to remove overburden provides increased productivity and flexibility to a surface mining operation. The utilization of such a system at the Texasgulf Inc. Aurora, North Carolina Mine has significantly improved the overall productivity of the mining operation. System flexibility is evidenced by adaptation to operation requirements such as mining area moves, movement of excavated overburden to designated sites, selective handling of overburden, spoil placement contouring, and providing an environmentally sound and safe operation. System productivity is evidenced by actual case studies relating to overall production, excavation rates, and cost effectiveness.

Jan 1, 1993

By Glenn Mallory, Margarete Kalin, Ben Romanin

A waste management area of a copper zinc mine which is expected to be generating acid exceeding 1000 years is used as a research facility to develop a passive treatment approach to decommissioning the site. One of the processes proposed to be implemented in a lake with a one million cubic metre volume is biological polishing. To determine the expected performance of the process, model is constructed from experimental data collected in the lake. The model results and the field data represent a weak fit, but the discrepancies are useful indicators of key factors affecting the process, such as iron cycling.

Jan 1, 1995

By Peri Mehling, Allister Brown

Environmental regulations concerning the processing of gold ores and the treatment and disposal of spent process solutions range from rigid standards in some locations to site specific options in several other jurisdictions. This paper examines the regulations and policies in two North American jurisdictions. Emphasis will be placed on the mill process and waste stream treatment and disposal, and implications for environmental impacts. Case examples of mine licence requirements will be discussed, with brief descriptions of individual treatment and disposal systems. Policies and environ- mental regulations within each jurisdiction will be examined in terms of potential environmental protection.

Jan 1, 1987

By Bert Allard, Åsa Sjöblom

The River Vormbäcken is the recipient of treated AMD from the Kristineberg mine site, northern Sweden, where mining of a complex sulfidic ore has taken place since 1940. Parts of the river flow through different kinds of wetlands. The changes in metal concentrations and water chemistry that occur upon passing these wetlands have been studied by analysis of water chemistry data from a number of stations along the river collected during 11 years of monthly sampling. It is concluded that the impact and functioning of wetlands cannot be elucidated from chemistry data alone. Future studies including e.g. reconstructed water flow are needed.

Jan 1, 2000

By P. F. Ziemkiewicz, A. S. Knox

Large-scale use of CCBs in mine environments involves filling surface and underground coal mines with ash to address hydraulic problems, AMD, backfilling and subsidence. The environmental risk of land filling CCBs is generally evaluated by the Toxic Characteristics Leaching Procedure (TCLP) or the Synthetic Precipitation Leaching Procedure (SPLP). However, there is doubt regarding the applicability of these tests to long-term CCBs leaching behavior in groundwater associated with coal mines. The Mine Water Leaching Procedure (MWLP) was developed to provide a site specific risk assessment tool. The MWL Pprocedure is presented in this paper and compared with TCLP as a study.

Jan 1, 2003

By Jeff W. Butwell

Mill flotation tailings impounded at the Gooseberry Mine site between 1976 and 1984 were determined to be an economic source of gold and silver recoverable by standard heap leach technology in conjunction with feed agglomeration. Metal recovery at 85 percent Au, 75 percent Ag is attained on properly agglomerated (pelletized) tailings which average 85 percent -75 micron. Because the impounded tailings averaged over 18 percent moisture (32 percent moisture maximum at depth) in place behind the storage dam, the mining method, mixing and agglomeration technique, and materials handling practice were major considerations in making this operation a financial success.

Jan 1, 1990

By E. V. Kuzmin

The rock properties improvement means the exchange of natural properties: increase of stability, strain and compress tension, reduction of gas-liquid filtering property, increase Jung- module, other mechanical and physical parameters of rocks by injection the hardening materials, such as polymeric pitches, micro-or geocements by special technology under high pressure, to fill cracks. Flow of liquid materials between the rock units and hardening under high pressure create full redistribution of rock pressure in rock massif. There are many reasons to use this technology in underground mining, tunnelling, creation barrier technology in raioactive, chemical and other danger material site etc.

Jan 1, 1996

By R. W. Reisinger

An historic underground copper mine in Wyoming is discharging neutral but copper-laden water into a pristine creek. The EPA-deferred site qualifies for reclamation by the Wyoming Abandoned Mine Land (AML) program. The cleanup goal is to restore the discharge so that the creek can eventually support a trout fishery. Hydrological and geochemical investigations underground have suggested two sources of mine water: one clean and the other containing copper. Results of bench-and pilot-scale tests support the viability of using low-cost passive treatment techniques to reduce copper concentrations in the near-freezing mine discharge.

Jan 1, 2000