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By S. A. McGhee

Introduction ASARCO's Ray Operations include an open-pit copper mine in the Mineral Creek Mining District of Pinel County. The district is located in east central Arizona, 132 km (82 miles) southeast of Phoenix, AZ, and 126 km (78 miles) north of Tucson, AZ. The mine lies 8 km (5 miles) north of the Gila River in Mineral Creek Valley, between the Tortilla Mountains to the west and the Dripping Springs Range to the east. The rich copper deposits of the Mineral Creek mining district were first noted by a US Army Officer in 1847. The Ray Copper Company was the first major operation in the area. The company was named after the Ray mining claim, which was one of the earliest recorded claims. After decades of sporadic and unsuccessful mining ventures, the Ray Consolidated Mining Company was formed in 1910. The company introduced one of the first successful block caving operations in the world. In 1933, the Kennecott Copper Corporation acquired the Ray Consolidated Mining Company and continued operation of the mine under the same name until 1943, when the property was renamed the Ray Mines Division of Kennecott. Underground mining continued until 1955, when the mine was converted to an open pit operation. In November 1986, ASARCO Inc. purchased the Ray Mines Division and related facilities from Kennecott. The purchase also included the Hayden concentrator and the Ray Smelter, located approximately 32 km (20 miles) from the Ray Mine. This paper summarizes the 54,400 tpd (60,000 stpd) in-pit crusher and overland-conveying system and the 24,200 tpd (30.000 stpd) copper SAG concentrator and tailings disposal system constructed at ASARCO's Ray Complex - Ray Operations. General description of facilities The Ray concentrator includes a sulfide SAG concentrator, a "relocatable" in-pit primary-crushing plant and overland-conveyor system, a concentrator tailings-disposal system and plant ancillary facilities, The major elements of the project include: • A relocatable Fuller-Traylor in-pit 1524-mm (60-in) x 2261-mm (89-in) primary gyratory crusher at the 442 m (1450 ft) mine elevation. The crushing plant has a nominal capacity of 54,400 tpd (60,000 stpd) of sulfide ore. • A 1524-mm (60-in) wide x 1253-m (4110-ft) long overland belt conveyor, which runs from the in-pit crushing facility to a transfer station serving both the Ray Concentrator and the existing Hayden concentrator railroad load-out facility. • A 1524-mm (60-in) wide x 152-m (500-ft) long stackerbelt conveyor, which delivers a nominal 27,200 tpd (30,000 stpd) of ore from the transfer station to a 23,600 t (26,000 st) live-capacity coarse-ore stockpile serving the Ray Concentrator. • A nominal 27,200-tpd (30,000-stpd) concentrator, including semiautogenous grinding, flotation, copper concentrate filtration and associated plant ancillary facilities. • A tailings disposal system. Flotation tailings are pumped from the Ray Concentrator to a 122-m (400-ft) diam. thickener, located 4.8 km (3 miles) southeast of the Ray Concentrator site. The thickener overflow is pumped to two 76.2-m (250-ft.) diam. concrete process-water reservoirs. The thickener underflow, at 45% solids, is pumped to a new tailings disposal site located at Elder Gulch. • An HDPE-lined temporary-containment area to collect material from Ray Concentrator plant upsets and local storm-water run-off from a 100-year, 24-hour rain event. •A reclaim-water system from the Elder Gulch tailing pond area to the Ray Concentrator. • A 610-mm (24-in.) diam. x 31.9-km (19.2 mile) long fresh-water pipeline from the Hayden fresh-water-well field system to the Ray Concentrator. The overall process design criteria for the new Ray Concentrator is based on a nominal throughput of 27,200 tpd (30,000 stpd) of ore at 90% plant availability. However, based on the maximum performance capacity of the installed grinding equipment, it may be possible to achieve a sustained operating level in excess of 36,300 tpd (40,000 stpd) when processing soft ores. The balance of this paper will cover the major process systems including:

Jan 1, 1995

By David G. Thompson

There are basically two commonly used methods of drying washed coal. They are mechanical drying (sometimes called dewatering) and thermal drying. The common methods of mechanical drying are by using vibrating screens, cross flow screens, sieve screens or Vor-Siv, vacuum filters and centrifugal dryers. With thermal drying, the common types include direct fired fluid bed, rotary drum, flash or suspension, vertical tray or cascade continuous carrier or vibrating fluid bed dryers and hollow screw dryers. In the past, it has more or less been a general rule that any time the total product is being washed, both mechanical and thermal drying was required. The reason for this was that a product moisture of 3 to 4% was required and thermal drying was and is the only practical method by which this can be accomplished. With the advent of air pollution controls and the ever increasing concentration on dust elimination, a 3 to 4% moisture product is no longer practical in either the preparation plant or in the processing plants which utilize the coal. Under the new standards, it is desirable to have a product with a 6.5 to 7% surface moisture. With this moisture range, dusting, due to handling, will bc kept at a minimum.

Jan 1, 1975

By Farzad Moradpouri, Kianoush Barani, M. R. Azadi

The aim of this paper is to assess the effect of microwave treatment on copper sulfide ore for ball milling and bed breakage. Liberation analysis of ground products in eight size fractions showed that microwave pretreatment liberated more chalcopyrite particles from the bed breakage product than the ball mill product. In bed breakage, microwave pretreatment caused a 2% increase in chalcopyrite liberation on average. Microwave pretreatment produces more elongated particles in ball milling and more rounded particles in bed breakage, respectively. Microwave pretreatment produces coarser chalcopyrite particles with a wide range of sizes. This effect is more significant in bed breakage compared with ball milling. Micro-flotation test results showed that in ball milling, treated and untreated materials have similar metallurgical performance and there is a little difference (1%) between the average Cu recovery values. However, in bed breakage, the average recovery for the treated materials is about 5% higher than the untreated materials.

Jul 8, 2021

By Dipl. -Ing. Mertens

Gentlemen: I am pleased and regard it as a priviledge to give you a report on rapid roadheading with heading machines in the coal mining industry of Western Germany. Importance of Heading Operations in the West German Coal Mining Industry Every year about 770 km of headings are driven In the seams of the West German coal mines, most of them gate roads, the rest rise headings, to open new faces. In thick seams the heading operations are carried out entirely in the coal, in thin seams the country rock has to be ripped. The total length of 770 km corresponds to a rock volume of roughly 9.5 million m3; this figure underlines the importance of the heading operations in the coal mining industry of our country.

Jan 1, 1970

By D. W. Alberter

I consider it a great pleasure and distinction to be invited to appear before your organization to discuss our experiences with a comparatively new system of what is known as a "Full Dimension" extensible conveyor system. One of these systems has been operating in our Diamond Smokeless Mine, Boltz, Pennsylvania, since 1959 servicing a continuous mining machines For those of you who are not familiar with this method of transportation, I would like to offer an explanation.

Jan 1, 1962

By Daniel A. Wasson

A review of the history of boosters is given with examples of the prominent types that have been made commercially. The performance and design features of protected core boosters are discussed in detail. A new gel booster is discussed with its advantages to the mining industry. Booster size, hole configuration, performance and safety aspects are reviewed. Important features of boostering in above ground and underground blasting are related to an economic analysis. This presentation will cover different types of boosters commonly used in mining. However, for the purpose of this paper a few terms need to be defined to clarify the action of different parts of a priming system. Booster* - "Any unit of explosive or blasting agent to be used in a charged hole for the purpose of perpetuating or intensifying the initial detonation". Primer* - "A unit, package or cartridge' of explosives containing a detonator or detonating cord which is used to transmit detonation to other explosives or blasting agents". Detonator - A device for initiating a detonation from a flame or a small electric current, the former being represented by a fuse cap and the latter an electric blasting cap.

Jan 1, 1981

By F. L. Wilke

In the german hard-coal mining industry the mechanization of longwall faces and the machinery used for the extraction process have reached such an extent, that an extensive increase in productivity and face performance is not likely to be expected. At present, the greatest amount of man-shifts is needed for operations such as tunneling, transportation and haulage (fig. 1.). The most restrictive parameter, especially considering the possible ad- [ ] vance rate of faces, is the comparatively low advance rate achieved in drifting operations. Therefore improvements in productivity and advance rates of drifting operations will have considerable influence onto the extraction rate of the faces. The importance of drifting operations - and especially the so-called "conventional drifting by drilling and blasting" within the scope of long- term planning strategy of the german hard-coal mining industry is reflected by the development factor. This factor is given by the ratio: cubic meters of rock excavated in drifting per 1.000 tons saleable coal produced. In 1973, which is considered to be the beginning of the oil-crisis, this factor was determined to be 17.7 m3/ 1.000 tons sale- able coal.

Jan 1, 1982

By Morris Loshinsky, George Ziegler

The New York City Transit System is celebrating its Diamond Jubilee this year. In 1904, 9.3 route miles of New York's first subway was placed in operation in lower Manhattan. Since that date the system has grown to 230 route miles and 458 stations (See Exhibit #1). The age of the system immediately provides a clue to the nature of our construction activity. While we must always plan for the future and expand the system in the direction of the future needs in New York, a substantial amount of time and money must be channeled towards the modernization and maintenance of the existing system which provides vital transportation for 3-1/2 million passengers a day. This paper however will be directed to our New Route's Construction and, specifically, to three rock tunnel and cut and cover sections presently under construction. Currently, New York is engaged in the construction of about 9 New Route miles of structure. Briefly, the 3 Sections we will discuss are as follows: Route 131-A Section 5A is a 4 track structure in Manhattan and includes the new Lexington Avenue Station. This 1240 foot long section is located between Park Avenue and 3rd Avenue and is a combined cut and cover and rock tunnel section under 63rd Street. Route 131-A Section 5B is an intricate 2423 foot long 4 track rock tunnel section extending from 3rd Avenue to the FDR Drive under 63rd Street in Manhattan.

Jan 1, 1979

By R. M. Barker

The historic Getchell property, near Golconda, NV, is being mined from the Getchell Main Under- ground workings, a footwall extension of the Getchell open-pit deposits along the Getchell fault. Drift-and-fill techniques are used to extract the ore through a ramp access. The adjacent Turquoise Ridge deposit is under development by two vertical shafts. These two mines will continue to provide feed to the Getchell's 2.9 ktld (3,200 stpd) mill/autoclave circuit. This will take Getchell Gold from its current production rate of 6.2 t/a (200,000 oz/year) to more than 12.4 t/a (400,000 oz/year) by 1999.

Jan 1, 1997

By G. L. Mowrey

One critical element of the U.S. Bureau of Mines (Bureau) autonomous mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include vibration, passive infrared, radar, and natural gamma radiation (NGR). To establish which CID sensor technologies need to be developed for a given seam, coal and adjacent rock samples (i.e., immediate roof and floor) are being collected from selected major coal seams in the U.S. and are being analyzed in terms of NGR and other geophysical measurements. Results of the NGR measurements indicate that, in general, all shale and shale-like materials (e.g., drawslate, slate, and fireclay) have higher NGR readings than the coal seam. Consequently the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1990

By S. A. Pirzada

A thermal plasma assisted laminar flow reactor has been used to evaluate the kinetics of converting alumina to sodium aluminate in flight. Free energy minimization calculations were used to determine experimental conditions. The experimental variables include: alumina particle size, alumina/sodium nitrate molar ratio, temperature and residence time. A mathematical model for the conversion was developed and validated. Experimental and mathematical results are presented.

Jan 1, 1996

By J. L. Sloughfy

The size distribution and mechanical strength of the iron ore pellet burden are important parameters in determining the efficiency of the blast furnace. From the very outset, the guiding principle of our pellet quality improvement program was that these parameters are also the key to improving productivity and cost control at the pellet plant. Recognizing the need for improved blast furnace burdens and for higher productivity and lower costs at the pellet plant, Carol Lake operators, in conjunction with the IOC Pellet Quality Committee, established the following goals for the improvement of Carol pellets: [ ]

Jan 1, 1981

By Hee-Young Chung, In-Mo Lee, Jeongjun Park, Hangseok Choi, Seok-Won Lee

"When using a Tunnel Boring Machine (TBM) during tunneling work, unexpected ground conditions can be encountered that are not predicted in the design stage. These reduce the stability of tunnels, and can result in considerable economic losses. This paper analyzes the potential risk events that may occur due to risky ground conditions. A resistivity survey is utilized to predict the risky ground conditions ahead of the tunnel face during construction. The potential risk events are evaluated considering both the occurrence probability and the impact. A TBM risk management system that can suggest proper solution methods for potential risk events is also developed. Multi-Criterion Decision Making (MCDM) is utilized to determine the optimal solution method to handle risk events. Lastly, an actual construction site, at which a risk event occurred during tunnel construction, is analyzed utilizing the Earth Pressure Balance (EPB) Shield TBM, to verify the efficacy of the proposed system.INTRODUCTION The Tunnel Boring Machine (TBM) method has been widely adopted in numerous tunneling projects because, as a mechanized tunneling method, it is also environmentally friendly, exhibiting minimal noise and vibration when compared with conventional tunneling method. In addition, it provides considerable economic benefits that allow for a high advance rate for long drives during construction. However, the TBM method has a limitation, as it is unable to deal with unexpected situations during construction, as the system is not capable of moving backwards. This leads to delays or even stoppages, and a corresponding increase in construction costs due to the need to arrange for alternative equipment and solutions. It is essential to retain systematic management in order to prevent or deal with unforeseen consequences such as the collapse of a tunnel face, ground surface upheaval or settlement, and construction delay due to water leakage during construction. Therefore, a systematic risk management system that is applicable during the construction stage of the TBM tunnel should be developed, taking into account the predicted risky ground conditions ahead of the tunnel face in advance."

Jan 1, 2016

By J. E. Gebhardt, L. Piga, G. Schena

The possibility of beneficiating a low-grade alunite ore from the Tuscany region of Italy was examined. Flocculation and flotation techniques were investigated to separate alunite and kaolinite from the ore, which also contained feldspar and quartz. Flotation was performed at pH 6.5 with oleic acid as collector and sodium silicate as dispersant. A concentrate containing 12% alunite with a recovery of about 65% and a concentrate containing 28% alunite with a recovery of 84% were achieved from the -38-µm feed samples containing 5.0% and 12.9% alunite, respectively. Poor recovery of alunite was achieved by flocculation methods.

Jan 1, 1999

When the Middle Ages were drawing to an end and Rotterdam, then still a small fishing port, began to extend its trade relations to continental ports handling general cargo, a development was initiated which was to give Rotterdam a predominant position in maritime traffic in Europe 300 years later. Despite many setbacks and the silting up of the mouths of the Rhine and Meuse rivers, the port experienced a new rise towards the end of the previous century after the dunes at Hook of Holland had been cut through as planned by Dutch engineer Caland. With its favourable location in the mouth area of the Rhine and a hinterland opened up by waterways it was merely a matter of the city council pursuing a far-sighted policy to make the best of these natural advantages. Thus new port installations were erected on the southern bank of the Meuse in the first quarter of this century, which were expanded in the course of the subsequent decades. The New Waterway became the main artery for industrial enterprises, in particular oil industries, which sprang up along its banks (picture 1). Whereas 30 years ago Rotterdam's Waalhaven, with its new jettees for general cargo and mainly bulk goods, was still one of the most modern terminals, the growing size of ships, which increased by leaps and bounds for tankers, in particular towards the end of the 'fifties, necessitated much larger harbour facilities built further and further towards deep water.

Jan 1, 1972

By A. J. Jeffery

Heat transfer to a fluid flowing through a rough duct has been shown by many researchers to be a function of surface roughness. The effect of roughness asperities on the duct surface is to turbulate the fluid as it flows through the duct, increasing frictional pressure losses and convective heat transfer rates, and also increasing the surface area per unit length available for heat transfer. These factors combine to increase the total costs to the mine in terms of refrigeration and fan power requirements. A measurement system designed to automate the collection of tunnel roughness information and based on an infra-red timed pulse laser has been developed at the Royal School of Mines in London. The system allows accurate, high resolution digital recordings of tunnel surfaces to be made in two or three dimensions. Software for analysing the data has been written, and the description of a complex surface via single numerical term has been explored. A relationship between the numerically measured surface roughness and the pressure loss of the ventilating air is being investigated with a view to establishing an alternative method of describing tunnel roughness. The paper describes the roughness measuring technique developed and the analytical techniques explored so far.

Jan 1, 1993

By W. C. Taylor

The present fuel situation indicates that, at least for the next 20 to 30 years, the burning of coal will be a main source of energy. All coal contains sulfur, which is converted to sulfur dioxide during combustion. The concentration of sulfur dioxide (SO2) in the resulting flue gas, for most coals, would exceed the limits established by the Environmental Protection Agency (EPA). Therefore, the sulfur must either be removed from the coal prior to its burning, or be collected from the stack gas before it reaches the atmosphere. There is currently a large amount of research devoted to methods of removing the sulfur from the coal before burning, or during combustion in fluidized beds with materials which trap the sulfur in the solid residue. The commercialization of these processes, however, is not expected in the near future. Flue gas desulfurization appears to be the best near term prospect of fulfilling current air quality control regulations. The lime/limestone wet-scrubbing methods are the most advanced flue gas desulfurization processes and will account for the majority of sulfur removal systems in electric power generation. There are currently at least 23 full-scale systems existing or under construction and 17 of these will use the lime or limestone wet-scrubbing process. (1)

Jan 1, 1974

By Timothy J. Orr, Jami M. Girard

A NIOSH study on occupational deaths between 1980 and 1989 indicated that in the United States, mining had the highest average annual fatality rate (3 1.9 per 100,000 workers) of any other major industry. Since "lack of training" was often cited as the primary cause of accidents, NIOSH has been investigating new methods for effective training. One such method is the use of low- cost, desktop computers to simulate a virtual mining environment. Computer-based training offers several advantages over conventional training because the computer programs provide a three- dimensional environment that allows the trainee to practice using evacuation routes, encounter mining hazards, and view mining operations without being exposed to any real danger. One major focus of the project is mine escapeway multiuser training using desktop virtual reality programs. Researchers have imported mine maps into the software for the purpose of practicing actual evacuation routes and procedures. Various scenarios for evacuation can be practiced in a three-dimensional computer simulation of the mine in a disaster situation, complete with smoke, fire, and other dangers. Depending on the trainee's job description (i.e., foreman, shift boss, beltman, etc.), certain tasks need to be performed in addition to navigating primary and/or secondary escape routes. Each scenario allows for individual or team-based training and provides a means to educate mine workers in hazard recognition and hazard avoidance. Using this program, mine workers can practice evacuating various mine layouts without the danger and expense associated with escapeway training in an actual underground mine. Each scenario can be changed to test the trainee's reaction in a variety of circumstances and run many times so the trainee can practice concepts. This training experience will help reinforce the knowledge acquired during more conventional classroom instruction, and the inherent flexibility of the program allows training materials to be tailored to meet the specific requirements of individual mines.

Jan 1, 2002

By T. J. Close

On September 10, 1991, Secretary of the Department of Interior Manuel Lujan deleted the Silver Peak Range North Wilderness Study Area from the list of U.S. Bureau of Land Management lands in Nevada to be considered for wilderness designation. This decision was based in part on the U.S. Bureau of Mines mineral investigation of the wilderness study area which found that it has indications of precious metals resources. The following is a summary of the results of that mineral investigation. The study area lies between the Silver Peak and Dyer mining districts of west-central Nevada. The Silver Peak mining district, to the east, has a long mining history dating back to 1907 when precious-metals-bearing veins were discovered. The major producer in the Silver Peak district was Sunshine Mining Company's Sixteen-to-One silver mine. During the Bureau's study the Sixteen-to-One mine was operating; it has since been idled due to low silver prices. Precious metals-bearing veins were discovered in the Dyer district, to the west of the study area, in the 1860's. Mineral activity in Dyer district consisted mainly of prospecting. The Silver Peak study area itself has no mining history and contains only a few mining claims, but the Bureau examined 13 mineralized sites, most previously unknown and unclaimed. These sites are along two zones that cross the study area from the Silver Peak to the Dyer mining district. The two zones transect a volcanic center of fractured and altered rocks that contain epithermal veins of quartz, calcite, and jasperoid with gold, silver, and base metals. At the surface these veins are poorly defined and poorly mineralized. The more than forty veins examined in the study area are as thick as 17 feet and as long as 1,000 feet. Samples from surface exposures of these veins contained as much as 0.02 ounce per ton gold, 2.1 ounces per ton silver, 1.0 percent copper, 2.6 percent lead, and 0.4 percent zinc. Analyses of the Bureau data disclosed no vein large enough or of high enough grade to be classified a mineral resource. However, most do have indications of silver-and gold-bearing resources at depth. Subsurface exploration had to be done on the vein at the Sixteen-to-One mine to outline reserves (a vein averaging about 22 feet thick and containing 6-to 7-ounces per ton silver); the same is true of veins in the Silver Peak Range North Wilderness Study Area.

Jan 1, 1993

By Ramiro da Conceição do Nascimento, Horst Guenter Feldhagen, Rafael Piumatti de Oliveira

Mixed hydroxide precipitate (MHP) is a nickel intermediate product that has economical benefits to downstream leaching of lateritic marginal ores. Usually, this product is subsequently processed and refined to produce nickel by hydrometallurgy, but an alternative route can be made integrating hydrometallurgy and pyrometallurgy. Assessing the overall consumption of ferroalloys to obtain stainless steel, as an increasing practice performed in China, the synergy of nickel extraction from laterites by leaching and precipitation asMHP with the production ofMHP agglomerates applied as rawmaterial to furnaces of ferronickel production is a very attractive practice. This work aims to further the technological development of an agglomerated product feasible to hydro-pyro integration. The agglomeration experiments were performed by traditional pelletizing (firing the pellets) and cold bonded pelletizing (aging the pellets by appropriate stocking). Appropriate compositionswere prepared withMHP, additives and binders for each of these routes. A specific study of binder composition was made to find an adequate melting point. The produced pellets were tested to prove their properties by crushing strength tests. The standardization applied to iron ore was followed. The best result of crushing strength was 98.52 daN/pellet. The agglomerates with approved crushing strength for use in electric furnaces were smelted to produce alloys containing nickel; the agglomerates were characterized by scanning electron microscopy. The alloy obtained was metallic ferronickel with sulphide precipitates. Therefore, MHP pellets can be precursors of nickel alloys, which have to be refined to obtain the desirable composition.

Jul 6, 2020