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By Rainer Kahrger

This paper is a follow-up to the paper presented at the SME meeting in April of 1996. Since then, the El Abra facility has been started up, 9 months ahead of schedule, and has processed about 45 million tons of ore and produced over 700 million pounds of copper. For those unfamiliar with the El Abra materials handling and leaching facilities, a brief overview of the facility is provided. The paper will then deal in detail with such aspects of Conveyor 103, the long regenerative overland conveyor, including: actual running resistance starting and stopping procedures emergency brake test at 10,000 t/h Additionally, we shall take the opportunity to report on a catastrophic culvert collapse in October 1996, which stopped the conveyor abruptly at full speed and under high load condition, causing a belt breakage. We would like to use this opportunity to thank the management of El Abra and Cyprus Amax for providing assistance and allowing us to present this paper. The El Abra team deserves a great compliment for building this one billion dollar facility in record time in a remote area of a high-altitude desert with no existing infrastructure, and for bringing it so quickly up to full operating capacity. The El Abra management had to assemble a completely new operator team. Considering the above circumstances, it took a great effort by all involved to achieve success. The official performance test which was required by the lending banks was successfully concluded in November 1997.

Jan 1, 1998

By David Wright, Jerome Chamfray, Anthony Harding, Brian Boye

Conway’s Law states that unless we intentionally design automation tools around what we need, we will simply replicate our existing processes. While we may achieve some savings this way, there is an opportunity for greater benefits if we re-imagine the way we, as an industry, perform design. This paper examines current technology and shows how even small departures from merely encoding what we currently do could reap significant benefits. From these examples a framework is developed for a new and innovative approach tvo automation that will allow us to design more quickly, to a higher quality, and communicate outcomes more effectively.

Dec 1, 2022

The efficiency of a coal mine ventilation circuit is usually measured by the ratio of the sum of the face quantities divided by the quantity supplied by the fans. Other types of systems use the power delivered to the power supplied to measure efficiency. This paper argues the case that the current measure may be inadequate and that by also looking at the power ratio, ventilation may be better managed. Problems associated with failing ventilation systems would be highlighted earlier so that crisis management could be avoided.

Jan 1, 2009

By Brett Zernich, Michael Krulc, Brett Robinson

This paper provides an account of the efforts undertaken to construct the Northeast Interceptor Sewer (NEIS) project, which is a portion of a much larger program in Los Angeles, California to upgrade the city’s wastewater facilities. The project consisted of a number of elements, including both soft ground and rock slurry wall shafts, drilled shafts, soft ground EPBM mining, rock TBM mining, large diameter pipe placement, and underground structure construction. The need to complete the project under strict schedule constraints, in addition to the challenges of underground construction in congested urban areas, necessitated the work be undertaken with the proper balance of state of the art equipment, and thoughtful planning. The paper will detail the means, methods, and equipment used on the project, as well as discuss several of the unforeseen conditions encountered during construction.

Jan 1, 2005

By J. R. P. Aguirre

Minerales Monclova, S.A. de C.V. (MIMOSA) is owned by Grupo Acerero Del Norte (GAN). This company has 4 underground coal mines and 1 open pit to feed it?s steelmaking facilities located in the city of Monclova in the North of México in the state of Coahuila. The current underground mines are Mine 3, 5, 6 and 7 and the future projects are Mines 8 and 9. In the last years Mines 2 and 4 have been closed because they finished their coal resources. The remaining mines have bigger production and developments requirements in order to accomplish the goals of the company. The mines have been working in deeper and gassier areas. These conditions have required improvements in the ventilation design and methane control systems for all the mines. In some cases the ventilation of some of the MIMOSA?S mines has been increased 80%, and besides this, an intensive methane drainage program has been applied using horizontal in-seam boreholes and gob wells. The short-term ventilation plan includes the construction of 3 new vertical shafts with 5 and 6 meters diameter for Mines 5, 6 and 7 and the purchasing of bigger new main and backup fans for each one of these mines. One of these vertical shafts and the purchasing of the first 2 fans is already in process. This paper will explain the evolution and results of the ventilation and methane drainage systems in MIMOSA and the ventilation planning for the future years.

Jan 1, 2009

By Michael J. Robison, Wojciech F. Klecan, Robert L. Horner

Since 1928, nearly 64 km (40 mi) of tunnel have been excavated within the relatively soft Cooper Group, more commonly known as the “Cooper Marl,” for water supply and transporting wastewater in the Charleston area. The majority of these tunnels are unlined and still in operation, while others collapsed shortly after excavating. Tunnel behavior and support requirements vary considerably in this material due to differences in geotechnical properties. The 4.8 km (3 mi) long, 2.4 m (8 ft) diameter Bushy Park Water Tunnel, completed in 1997 for Charleston’s Commissioners of Public Works(CPW), required no ground support. By comparison, the 1.6 km (1 mi) long, 2.4 m (8 ft)diameter Harbor Wastewater Replacement Tunnel now under construction needs continuous support close to the advancing face, despite being located in the same geological formation. Case histories and general guidelines for designing tunnels in the Cooper Marl are presented.

Jan 1, 2001

By Ray E. Harris

Introduction A resource of more than 122 Gt (134 billion st) of minable trona and mixed trona and halite underlies an area of about 3400 km2 (1300 sq miles) west of Green River, WY (Culbertson, in preparation) (Fig. 1). In 1982, the total domestic consumption of soda ash (refined trona) was 6 Mt (6.7 million st) (Kostick, 1983). About 90% of this came from Wyoming trona. This enormous deposit occurs in the Wilkins Peak Member of the Green River Formation that is of Eocene age. This formation is derived from sediments deposited in a large lake named Gosiute. Lake Gosiute occupied the Green River Basin in southwestern Wyoming some 38 to 54 million years ago. The Wilkins Peak Member represents a restricted, evaporite-rich cycle of deposition when the trona deposits were formed. A total of 42 trona beds are known. Of these, 25 are of sufficient thickness and extent to be considered minable (Culbertson, in preparation). The production of sodium compounds from the trona deposits in the Wilkins Peak Member began in 1896 when wells were drilled within the present boundaries of the town of Green River. The purpose of the drilling was for extraction of sodium carbonate brines. Sodium carbonate (sal soda) was removed from these brines at a plant in Green River. Bedded trona was discovered in 1938 in a core from an oil well drilled south of Westvaco. In 1947, the underground mining of trona began. Production has continued from 1948 to date. Currently, five companies are mining trona and producing soda ash from the Wilkins Peak Member in Wyoming. Additionally, Allied Chemical Co. mines and processes trona for Church and Dwight's sodium bicarbonate (baking soda) operation in Green River. Competition in the soda ash industry depends primarily on the efficiency of mining and refining, allowing for lower-cost production. Newer plants and mine designs should increase efficiency. Solution mining holds promise as an even lower-cost method of mining. Employment in the soda ash industry is declining since the newer mining and refining methods are less labor intensive. Declines in employment, however, may be offset as production increases. Due to the large resource, the availability of minable trona should not be a problem for perhaps hundreds of years. Geology of Wyoming trona deposits Forty-two beds of trona or mixed trona and halite occur in the

Jan 10, 1985

By Robert J. F. Goodfellow, William A. T. Meakin, Kevin Clarke, Eric Cole

INTRODUCTION New York City Water Supply—Background and History Since the 1840s New York City has been developing the largest, and perhaps, the best urban water supply and distribution system in the world in terms of quality and reliability. One of the engineering marvels of the modern world, the New York City water supply and distribution system serves a population of almost nine million, including residents in nearby Westchester, Putnam, Ulster, and Orange Counties of New York State. The average daily supplies presently are running at almost 60 m3/sec(about 1,350 million gallons per day). The watershed for the New York City water supply system, under the jurisdiction of the New York City Department of Environmental Protection (NYCDEP), consists of19 reservoirs and three controlled lakes, and covers an area of approximately5,000 square kilometers (about 2,000 square miles) north of New York City. The watershed total available storage capacity is about two billion cubic meters (560 billion gallons) and is divided into three reservoir systems: the Catskill and Delaware watersheds located West of the Hudson River; and the Croton watershed, located east of the Hudson River, see Figure 1. The first element of the system, the Croton Aqueduct, started operations in 1842.Through several updates and expansions, the present-day Croton system was in place by 1911, providing a potential maximum supply of about 15 m3/s (about 340 mgd). The system includes ten reservoirs and three controlled lakes. In the late 1800s, with the tremendous growth of the City, New York City water engineers began to look for additional sources. Between 1907 and 1929, the City acquired water rights and constructed a new 148 km (92 miles) Catskill aqueduct to convey water from the Ashokan Reservoir to the City. The Catskill system also included the construction of the Kensico and Hillview Reservoirs just north of the City,

Jan 1, 2005

By Scott Ellenbecker

Mining has evolved in recent years, taking steps forward in the way that the industry is considerate of the environment and the communities in which it operates. Technology plays a major role in that evolution. Osisko Mining?s Osisko Mine near Malartic, Quebec is developing a new way of doing business. One manager said, ?We are building the Osisko culture,? but the company is doing many things that could become industry changers. Much of the change is driven by mine ownership and management to offer a better workplace and better community relations. Mining equipment manufacturers are changing, too, by engineering products with more operator comfort, fuel economy, ease of maintenance and more cleanly designed machines. And for those drills working close to communities, smaller bore sizes and sound retention are just two changes for the better.

Jan 1, 2012

The title of “the world’s biggest volume-produced hydraulic breaker,” that was held for more than a decade by the Atlas HB 7,000, changed hands with the launch of Atlas Copco’s HB 10,000 at bauma 2007. A service weight of 10 t (11 st) and up to 50 percent higher productivity represent major steps toward a new market segment: the use of hydraulic breakers as cost-efficient production machines for primary breaking and as a true alternative to drilling and blasting. The HB 10,000 has all the technical features developed by Atlas Copco for its hydraulic breakers and includes: StartSelect — the breaker’s start-up and shut-down behavior can be adapted to the conditions. AutoControl that ensures an optimized balance of impact energy and impact frequency to maximize percussive performance. Auto-Control also reduces blank firing force and controls energy recovery. PowerAdapt — if oil pressure is too high, the breaker shuts down automatically. This prevents downtime and is particularly useful when breakers are used on different carriers. DustProtector II — a combination of multiple strippers prevents abrasive rock dust and foreign bodies from penetrating the lower breaker section. Conti- Lube II — the automatic lubrication unit guarantees optimal lubrication of the breaker at all times.

Jan 1, 2007

By Y. P. Chugh

During late 2010, a scientifically founded water spray system was developed for continuous miners (CM) (Patent Pending) that reduces respirable dust exposure for miner operator by about 30%. It includes engineered sprays around the cutting drum, outer bit-ring sprays, chassis sprays and side cutter boom sprays. About 3.6 ? 4.5m (12-15 ft) behind these sprays is additional sprays that spatially cover the area between the CM chassis and the mine roof and ribs. The spray system uses approximately the same volume of water as currently used on CMs with similar operating pressures. An Illinois mine decided to implement these concepts on a CM during rebuild stage. Dust control performance of the rebuilt CM was evaluated using gravimetric sampling and real-time monitoring using multiple personal dust monitors (PDMs). The average results based on about 105 cuts show about 30% and 20% reduction in dust exposure for the miner operator, and the haulage unit operator. Visibility in the mining areas was also significantly improved. The coal company has already decided to implement the system on all their CMs.

Jan 1, 2012

By Tianzu Yang, Weifeng Liu, Lin Chen, BOYI XIE, DUCHAO ZHANG, HUI XIAO

In this study, the oxygen-rich bath smelting process of copper dross was simulated using Factsage software. It was found that the two-step simulation results agreed better with the industrial data, especially in the speiss. Bismuth (Bi), lead (Pb), antimony (Sb), arsenic (As) and copper (Cu) contents in the speiss by two-step simulation differed from the industrial data by 0.6, 0.8, 2.6, 7.2 and 8.6 weight percent, respectively. The two-step simulation results indicate that the speiss partitioning of Sb, As and Cu increased from 60.1, 32.3 and 27.5 percent to 81.6, 67.8 and 47.2 percent, respectively, with the smelting temperature increasing from 1,050 to 1,250 °C, while the metal partitioning of Sb and Cu increased from 0 and 2.7 percent to 15.2 and 13.3 percent, respectively, with the separation temperature increasing from 400 to 700 °C.

By W. W. Wen

A continuous pilot-scale test of the GranuFlow Process was conducted using a screen- bowl centrifuge for the dewatering and reconstitution of column flotation concentrate at a coal preparation plant in Virginia. In this test, a slipstream of the fine-clean-coal slurry from the column flotation concentrate was treated with a bitumen emulsion before dewatering. The treated products from the screen-bowl centrifuge appeared to be dry and in a free-flowing granular form, while the untreated products were wet, sticky, and difficult to handle. Specifically, test results indicated that the average moisture contents of the dewatered coal were 35.7, 35.5, 32.6, 29.9, and 26.5 wt% with Orimulsion additions of 0,0.7,3.2,4.8, and 6.4 wt%, respectively. The handleability and dust reduction of the dewatered coal product were also vastly improved.

Jan 1, 1997

Tracer gases are an effective method for assessment of mine ventilation systems, but their dispersion characteristics can differ substantially as ventilation parameters, such as flow path and velocity, vary. This research utilizes Computational Fluid Dynamics (CFD) to model a simplified full scale model mine, details a sensitivity study examining mesh size for an underground coal mine simulation, and examines gas dispersion parameters to determine the optimal model methods for simulation of tracer gases in underground coal mines. These models can be used to determine how a given tracer gas profile might be generated in a mine or areas of a mine that are not accessible, for example, immediately following a mine disaster. Accurate simulation scenarios can allow for the remote determination of the status of the ventilation network, but the sensitivity of the simulation at mine scale must be carefully examined.

Jan 1, 2012

By Wu Xueling

9K medium was used to isolate iron-oxidizing bacteria from 27 sump water samples collected from Dexing Cop-per Mine, Chengmen Mountain Mine and Yin Mountain Mine, Jiangxi Province, China. Lead acetate and silver nitrate were used to enrich metal-resistant iron-oxidizing bacteria from the above water samples. Isolate 16 was isolated from the sample taken at Dexing Copper Mine. Growth experiments indicated that when incubated under lead acetate (3,500 mg/L), isolate 16 still carried out ferrous ion oxidation, while isolate H1, a less resistant strain taken at Yin Mountain Mine, had a tolerance level of only 400 mg/L. When assayed with other metals, i.e., Ag+ (240 mg/L), Hg2+ (0.9 mg/L), Cu2+ (32,000 mg/L) and Mg2+ (22,500 mg/L), isolate 16 still carried out ferrous ion oxidation while, on the other hand, isolate H1 exhibited much lower tolerance levels, i.e., Ag+ (60 mg/L), Hg2+ (0.1 mg/L), Cu2+ (19,000 mg/L) and Mg2+ (13,500 mg/L). Based on 16S rDNA sequence data, isolate 16 and H1 were both identified as Acidithiobacillus ferrooxidans.

Jan 1, 2007

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

The conventional rare earth element (REE) industry has historically sought to develop ore deposits where geologic processes have produced mineralized zones with commercially attractive REE concentrations. These deposits are extremely uncommon, particularly in the USA. Given the criticality of these materials and the need for sustainable domestic supply, the current research seeks to leverage other autogenous processes that lead to concentrated REE resources. One such process is the generation of acid mine drainage (AMD). AMD is very common in many coal mining districts and results from the exposure and oxidation of pyrite during mining. During the generation and migration of AMD, liberated sulfuric acid mobilizes several metal ions including REEs. Treatment of AMD is required under U.S.C §1251, the Clean Water Act, and often consists of neutralization, oxidation, and metal hydroxide precipitation. To investigate the deportment of REEs during this process, a field sampling campaign was undertaken, whereby the concentration of REEs in AMD and AMD precipitates was measured directly. In the nine sites evaluated in this study, the REE concentrations of the precipitates varied from 29 to 1286 ppm with an average of 517 ppm among the sampled sites. The individual elements were enriched compared with the associated bulk Northern Appalachian (NAPP) coal material by factors ranging from 3 to 15. Furthermore, the distribution of REEs in all precipitate samples favored the heavy REEs (HREEs) when compared with traditional REE ores. This research represents the first part of multi-part research endeavor to characterize, classify, and determine the practicality of refining REEs from AMD and its by-products.

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

The conventional rare earth element (REE) industry has historically sought to develop ore deposits where geologic processes have produced mineralized zones with commercially attractive REE concentrations. These deposits are extremely uncommon, particularly in the USA. Given the criticality of these materials and the need for sustainable domestic supply, the current research seeks to leverage other autogenous processes that lead to concentrated REE resources. One such process is the generation of acid mine drainage (AMD). AMD is very common in many coal mining districts and results from the exposure and oxidation of pyrite during mining. During the generation and migration of AMD, liberated sulfuric acid mobilizes several metal ions including REEs. Treatment of AMD is required under U.S.C §1251, the Clean Water Act, and often consists of neutralization, oxidation, and metal hydroxide precipitation. To investigate the deportment of REEs during this process, a field sampling campaign was undertaken, whereby the concentration of REEs in AMD and AMD precipitates was measured directly. In the nine sites evaluated in this study, the REE concentrations of the precipitates varied from 29 to 1286 ppm with an average of 517 ppm among the sampled sites. The individual elements were enriched compared with the associated bulk Northern Appalachian (NAPP) coal material by factors ranging from 3 to 15. Furthermore, the distribution of REEs in all precipitate samples favored the heavy REEs (HREEs) when compared with traditional REE ores. This research represents the first part of multi-part research endeavor to characterize, classify, and determine the practicality of refining REEs from AMD and its by-products.

By Bart Bartholomew, Randall J. Essex

INTRODUCTION In June of 2004, at the North American Tunneling Conference in Atlanta, an all-day workshop was conducted to review the application of Geotechnical Baseline Reports (GBRs) for underground construction. The moderator for the program was Bart Bartholomew, former President of Fruin Colnon Construction Company. The program involved commentary by a panel of engineers, owners, contractors, and legal representatives within the North American tunneling industry, as well as an extended audience discussion. The panelists were: Peter Douglass, President, Peter Douglass, Inc. Randall Essex, Executive Vice President, Hatch Mott MacDonald Joseph Gildner, Deputy Director for Technical Services, Sound Transit Randall Hafer, Esq., Kilpatrick Stockton Robert Fitzgerald Esq., Watt, Tieder, Hoffer, & Fitzgerald Kirk Samuelson, Senior Vice President, Kiewit Construction Group DEVELOPMENT OF PROGRAM FORMAT The focus of the program was to assess the state of the practice in the preparation of GBRs, and to discuss improvements that could and should be made with regard to their preparation, interpretation, and application. The approach used to achieve this focus in the broadest possible way was unique, in that it involved the panelists’ preparation of the workshop format and materials months before the presentation of the workshop. First, each of the six panelists was selected by the moderator based on their reputation and involvement in their respective fields of expertise, taking care to maintain balance and contrast within the collective pool of talent assembled. Following selection and agreement to serve on the panel, each panelist was asked to independently submit to the moderator a list of the six most pressing issues involving GBRs that they each frequently encountered in their individual professional experience. Each was asked to rank their issues in descending order of perceived importance. This process resulting in a pool of thirty-six potential or “candidate” issues for use in the workshop program. Contrary to the moderator’s expectations, there was surprisingly little duplication among the thirty-six issues submitted.

Jan 1, 2005

By R. P. King

The MODSIM mineral processing plant simultor is used to find optimal combinations of target separation specific gravities in a typical modem coal washing plant. A plant that is set up with these optimal targets can deliver up to 10% more yield at the same ash content as the same plant set up with separation targets chosen by conventional methods. MODSIM is the only simulator currently available that can simulate the liberation of pyrite and other mineral matter during open- and closed-circuit grinding operations. The simulator can therefore be used to assess the benefits of grinding operations in the flowsheet.

Feb 24, 1997

By J. W. Wilson, P. C. Graham

SUMMARY The Witwatersrand quartzites in which South African gold mining operations are moat exclusively conducted, are notoriously difficult and costly to drill. Despite this situation, however, with the high cost of developing new mines and extending existing mines, together with the rising cost of labour and mining problems resulting from the ever-increasing depths of workings, the demand for raise-boring in these formations is increasing rapidly. Not only is the demand for raises and shafts increasing, but also the length and size of these excavations. Raise-boring studies carried out in South African gold mines have indicated that increased penetration rates and possibly reduced costs could be obtained if higher thrusts were available at the reaming head. Until fairly recently there has been no raise-boring machine suitable for underground use that possessed the thrust and torque characteristics necessary to achieve high penetration rates in hard abrasive quartzite formations and the cutters available were not really developed for high loading. In response to these requirements a raise-borer, the Robbins 83R was designed and built in Seattle, U.S.A. for the Anglo American Corporation. This machine is operating in South African gold mines and is currently being used at a depth of 12 000 ft below surface in one of the. Group's mines. The initial raises bored have substantiated that increased penetration is attainable at high thrust and it is now apparent that the machine is sufficiently versatile to drill raises of up to 12 ft in diameter in quartzite formation over a length of 2 000 ft.

Jan 1, 1974