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By J. W. Jamieson, J. Escartin, A. Steinführer

Evidence of hydrothermal activity on two Mid-Atlantic Ridge oceanic core complexes (OCCs), at 13º30’N (the Semyenov 1 through 5 fields) and 13º20’N (the Irinovskoe field) (Fig. 1) were studied using CTD casts, dredges, TV-grabs and SP surveys during previous research cruises to these sites (Cherkashev et al., 2013, McLeod et al., 2009). In late 2013, the Semyenov and Irinovskoe fields were revisited, this time with an autonomous underwater vehicle (AUV) and a remotely-operated vehicle (ROV) during the ODEMAR (Oceanic Detachments at the Mid-Atlantic Ridge) cruise on the French research vessel "Pourqoui Pas ?". Here we present the first visual surveys and direct sampling of these vent sites. High-resolution (~2 m) bathymetry of the 13º30’N and 13º20’N OCCs and their associated vent fields was collected during 4 and 5 AUV dives, respectively, using the GEOMAR AUV "ABYSS" (Fig. 1). These surveys were flown between 70 m and 100 m above the seafloor, typically at a constant height to reduce vehicle movement. The AUV was equipped with Eh, turbidity, and temperature sensors in order to detect active hydrothermal venting. Over twenty ROV dives with the ROV "VICTOR 6000" allowed for the visual exploration of the OCCs and collection of 59 hydrothermal rock samples from the vent fields. As a result of these exploration activities, the first robust estimates of the size of the deposits, and the geologic controls on sulfide accumulation at these sites can be determined.

Sep 1, 2014

By T. S. Golosinski

Introduction Typical dragline rigging includes several sets of ropes: hoist ropes, drag ropes, dump ropes and boom suspension ropes. The drag and hoist ropes contribute most to the dragline operating cost. Both work in very difficult conditions and wear out rapidly. As a result, frequent rope changes are required resulting in substantial cost and productive time loss. Although performance of rigging has a profound impact on dragline efficiency, there are no common, industry accepted standards related to its selection, operation and maintenance. Little information on the subject is available and the practice differs widely throughout the industry. The performance of drag and hoist ropes depends on: •rope construction that should closely match requirements of the specific application, rope operating conditions and its maintenance and • correct definition and application of the rope discard criteria so that full advantage of the rope can be taken without endangering safety of its operation. This paper reviews the present practice related to all these factors. Its findings are based on the wide survey of the present industrial practice. Field survey In total, 33 North American dragline applications were surveyed of which 17 were Bucyrus-Erie machines, 10 were Marion and six were Page (now P&H). Most of the draglines were stripping overburden in coal mines, but the survey also included some unique applications such as phosphate mining in Florida and oil sand mining in Alberta. Hoist drive power of the surveyed machines varied from 300 to 7775 kW (400 to 10,400 hp). Drag drives varied from 300 to 5815 kW (400 to 7800 hp). Boom lengths varied from 37 to 110 m (120 to 360 ft). Bucket sizes varied from 5 to 96 m3 (6 to 115 cu yd). The hoist and drag ropes installed on the surveyed machines were supplied by 10 rope manufacturers and differed widely in type and construction. Most common rope strand constructions included standard strands, Seale, Warrington, Warrington-Seale and Filler-Seale. Results of the survey [ ] Working conditions Working conditions of hoist and drag ropes are quite different. The first cope primarily with bending on rope drums, point sheaves and deflection sheaves, and with tension force imposed by the bucket and its load. The drag ropes are exposed to severe abrasion at the pit crest, and to severe bending and crushing at fairleads, all while coping with tension forces imposed by resistance of the bucket to dragging. Bending of drag ropes at house rollers and at rope drums is of minor importance for their performance. Differences in working conditions result in different wear patterns, which make it feasible to install discarded hoist ropes to further serve as drag ropes. The hoist ropes wear primarily due to fatigue breaks of wires, while the drag ropes are subject to severe abrasion of outside wires, rope deformation and internal wire-strand breaking. The last is often indicated by the reduction of rope diameter. The summary of working conditions for the surveyed draglines is shown in Table 1. For simplicity, Table 1 does not include the data on rope bending at the fairleads, nor at the deflection rollers and house rollers. Similarly, Table 1 does not include the data on drag rope bending (other than that on the rope drum), as its influence on rope life is insignificant in view of severe abrasion and internal wear taking place elsewhere. The following abbreviations are used in Table 1: [D - diameter of rope drum. DP - diameter of boom point sheaves. d - rope diameter x - mean value of the measured parameter. s - standard deviation of x B/d - average bending ratio of ropes B/d =(D+ DP)/2d n - operational safety factor of the rope (rope stength) x (number of ropes) n(bucket load + bucket weight)] In terms of D/d ratio, the working conditions of hoist and drag ropes are similar to that in other related industrial applications. However, the safety factors of the dragline ropes are lower, which requires them to carry relatively large tension forces. The last explains the fact that the life of dragline ropes is low when compared to other industrial rope

Jan 1, 1995

By Robin P. Gardner

The mechanistic approach to comminution consisting of incorporating particulate breakage functions into a suitable population balance equation has been developed by a number of researchers over the past decade or so. (1) To date this approach has been developed and demonstrated primarily for batch-operated, laboratory or small-scale ball mills. However, since industrial mills are mostly quite large and operated in the continuous mode; suitable population balance models and methods for obtaining the necessary breakage and other model parameters must be developed. This paper describes and investigates a radioisotope tracer technique for this purpose, Population balance models previously developed(2,3) are adapted for this study.

Jan 1, 1974

By Eugene F. Casey

An immersed tube tunnel is one which is composed of elements that are prefabricated in a dry dock or on shipways, usually away from the actual tunnel site, floated into position and then lowered into a preexcavated and graded trench below a body of water. The elements or segments are then connected to each other under water, and the entire immersed tube tunnel covered with a protective blanket. Because water is essential, this method of construction offers advantages in a relatively limited field. By the very nature of the method, lowering elements to the bottom of an underwater trench, immersed tube tunnels are primarily used for crossing bodies of water, such as rivers, bays, straits, canals, etc. Although this method of construction was first used for a subaqueous railway crossing under the Detroit River in 1906-1910 and again in 1912-1915, for a four track subway tunnel under the Harlem River in New York, the reason immersed tube tunnels construction has not been used more extensively is simply a matter of economics. Bridges, compressed air tunnels and similar structures could be constructed at a lower cost.

Jan 1, 1970

By A. T. Iannacchione

From 1990 to 1996, 16 states reported 92 injuries from falls of roof, rib or face in the more than 90 underground stone mines in the United States (Fig.1). Missouri, Pennsylvania and Kentucky accounted for 48% of the total number of injuries (Fig. 2). Of this total, 11 miners were killed. Of the 11 fatalities, 10, or 91%, were associated with unrecognized loose or failed rock within the roof beam. Additionally, unrecognized roof beam failures resulted in a majority of the falls of ground injuries occurring in underground US stone mines from1990 to 1996. This number is not large in magnitude. But a workforce of fewer than 2,000 miners makes for a high fatal-accident rate. The severity of the typical fall-of-ground injury is, in general, very high. About three-fifths of all roof, face and rib fall injuries were designated by the US Mine Safety and Health Administration (MSHA) as some kind of lost time accident. MSHA assigns each accident a severity value from one to six. A one represents a fatality, a two, a permanent disability and three, a lost time accident (Fig. 3).

Jan 1, 2000

By V. Svalbonas

Everybody has an opinion what the quality of a grinding mill head casting should be, yet extremely few take the time, or get the opportunity, to compare their opinions against fitness-for-purpose data. The real question is not how flawless the casting should/could be, but rather how long will ?this? casting survive in operation. To validate an opinion on this topic one needs either extensive historical data, or comprehensive experimental data, or preferably, a combination of both. The same data can also be used to establish the conservativeness, or lack thereof, of analytical prediction methods.

Jan 1, 2009

By Ben Roderds

The Waneta Expansion Project (WAX) is located near the existing Waneta Dam site at the confluence of the Pend d?Oreille and Columbia rivers, approximately 10 km (6.2 miles) south of Trail, BC, Canada. The WAX owners consist of a partnership between Fortis Inc., Columbia Basin Trust and the Columbia Power Corp. This design-build project was awarded to SNC-Lavalin in late 2010 and is expected to be operational in mid-2015. The WAX consists of a new 335-MW powerhouse, including two new Francis turbine units, each generating approximately 167 MW. The powerhouse is located downstream of the existing Waneta Dam, and will make use of excess water that would otherwise be spilled during the runoff season. Water will be funneled to the turbines through an intake structure and two 10.5- m (34.5-ft) diameter, concrete-lined Penstock Tunnels. A 10-km (6.2-mile) transmission line will connect the powerhouse to existing electrical grids. Redpath/FKCI Waneta Tunnelers (RFK) was subcontracted by the heavy civil contractor, the Aecon/SNC Lavalin (ASL) joint venture, to excavate the two penstock tunnels and install the cast-in-place concrete liner. RFK is a joint venture partnership between J.S. Redpath Ltd., an underground mine contractor located in North Bay, Ontario, and Frontier-Kemper Constructors ULC, a heavy civil tunneling contractor based in Nova Scotia, Canada. Since penstock tunnel excavation was planned using drill-and-blast methods with a significant grade of more than 17 percent, the combined experience of these two contractors was a perfect match.

Mar 1, 2014

By F. M. Doyle

Metal removal kinetics and metal ion selectivity in ion flotation were studied from a thermodynamic perspective. Surface tension data could be used with the Gibbs adsorption equation to quantitatively predict the metal ion removal kinetics in alkylsulfate-Cu systems. However, surface tensions predicted cation selectivity coefficients in the sodium dodecyl-sulfate (SDS)-Cu-Ca and SDS-Cu-Pb systems rather poorly, although the predicted order of the selectivity (Cu2+<Ca2+<Pb2+) was correct. Another thermodynamic selectivity model, which used the Grahame adsorption equation and a geometrical analysis, predicted cation selectivity coefficients that agreed very well with experimentally measured values.

Jan 1, 2000

By Jeffrey A. Pontius

The Cresson gold deposit is in the southcentral portion of the Cripple Creek mining district in central Colorado (Fig. 1). The deposit is hosted by a series of 32 Ma (Kelley, 1995) felsic to mafic, alkaline volcanic rocks that were deposited in a diatremal environment. Mineralization in the Cresson deposit is structurally con-trolled. It occurs as disseminated and vein type. Gold deposition is closely associated with potassium-pyrite metasomatism and quartz-telluride vein development(Pontius, 1992). The Cresson deposit is owned by the Cripple Creek and Victor Gold Mining Co. (CC&V), a joint venture between Pikes Peak Mining (67%) and Golden CycleGold (33%).

Jan 1, 1996

By Roland F. Beers

At East Union, Knox County, Maine, near the shore of Crawford Pond, an outcrop of basic rock has been known for more than a century. The occurrence has been regarded as an unusual type of peridotite-pyroxenite, containing disseminated and massive pyrrhotite with nickel, copper and cobalt in recoverable amounts. From the outcrop, the sulfide body had been mapped more or less continuously for a distance of two miles through geophysical methods of several kinds. This paper describes the methods in sufficient detail to evaluate their significance. A core drilling program has con- firmed the location of the conductor and offers a positive means of correlating the geophysical measurements with the physical properties of the ore body. The history of the exploration offers a unique opportunity to evaluate the method of multiple geophysical methods.

Jan 1, 1962

By P. Zhang

The use of phosphate depressants in the cationic flotation of silica from francolite in the Florida phosphate industry is rarely practiced. The occasional use of gelatinized starch derivatives and pH adjustments to assure a slightly alkaline flotation feed slurry pH have been used in some processing plants to improve selectivity. This paper presents a preliminary laboratory comparison of several potential phosphate depressants for use with the flotation of siliceous phosphates. It was found that starch is ideal for floating fine (-35 mesh) silica from phosphate, while sodium tripolyphosphate may be the best for coarser (+35 mesh) feeds.

Jan 1, 2009

By V. B. Achanti, A. W. Khair

Laboratory studies were carried out at West Virginia University to investigate the rock fragmentation mechanism by continuous miners using an automated rotary cutting simulator. The primary factors influencing the fragmentation process were found to be: bit spacing, bit geometry, depth of cut and cutting drum rotational speed. This paper presents the influence of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation process. Tree bits were used simultaneously on Indiana limestone while the bit tip angle was varied from 60° to 900. Bit spacing was varied from 2.54 cm (1 in.) to 5.08 cm (2 in.) while the cutting process was assessed for varying cutting depths. Restorable dust generated during the course of the experiments was analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism by continuous miners in terms of energy consumption and dust generation.

Feb 24, 1997

By J. R. Frederick

Introduction In response to industry needs and requests, Joy Mining Machinery is aggressively evolving a "game changing" system of underground development mining machinery. This entry-development system (EDS) project is concentrated on providing clean, protected and ergonomic operator areas and a quantum leap in productivity. To meet these goals, a virtually continuous and automated mining system is needed. Operators must be able to efficiently and ergonomically perform required functions from a protected environment. Health-related issues, such as respirable dust and noise, must also be addressed. A new concept system of integrated face equipment, from the continuous miner to and including advancing the section belt and services, is needed. Phase I of the project was aimed at developing the bolting technology required. Through acquisition of Cram Australia and joint development efforts with Canyon Fuel Co., Joy now has this capability. The test platform, known as the Joy Multibolter, has successfully completed its trials at Canyon Fuel&apos;s SUFCo Mine (Fig. 1). These tests validated the bolting technology and operator protection and ergonomic issues. Phase II includes the development and testing of an integrated mining machine (IMM) capable of advancing a heading 1.5 m (5 ft) while simultaneously cutting a fullface width (single pass) and installing a complete bolt pattern. The IMM, unveiled at MINExpo 2000, incorporates the bolting technology of the Multibolter with automated full-face cutting. This machine was designed to meet Joy&apos;s stringent health, operator protection and 300m/d (1,000-ft/d) productivity goals. Phases III through V will include development of processes and integrated haulage, ventilation, power, material handling and section services advancing equipment. Processes and equipment developed will be designed for seamless integration into a complete entry development system. The focus of this paper is the new continuous miner (IMM) development, proposed testing and expectations for the EDS. The IMM is scheduled for commissioning and trials beginning in April 2001 at the SUFCo Mine. SUFCo Mine Canyon Fuel Co. is jointly owned by Arch Western Resources and the Itochu Corp. of Japan. It owns and operates three coal mines in Utah: the SUFCo Mine in Sevier County, the Skyline Mine in Carbon and Emery Counties and the Dougout Canyon Mine in Carbon County. Incorporating state-of-the-art-mining technology and advanced mine management practices, the SUFCo Mine is one of the most efficient underground coal mines in the world. The SUFCo Mine is located approximately 50-km (30 miles) northeast of Salina, UT, in the Wasatch Plateau portion of the Uinta coal basin. The mine property consists of 9,900 hm2 (24,470 acres) with approximately 118 Mt (130 million st) of recoverable reserves. Public utilities and industrial concerns purchase approximately 95% of the coal mined at SUFCo through short- or long-term contracts. Coal reserves are extracted by longwall mining, and the panels are developed using continuous miners. The longwall face at SUFCo Mine is 283-m (930-ft) wide, and the seam height ranges from 2.4 to 4 m (8 to 13 ft). The two development sections are in full operation using Joy 12CM12 continuous miners. Two super longwall panels, under development in the northeast portion of the lease block, are 4,270-m (14,000-ft) long with a 283-m (930-ft) wide longwall face. Each panel contains approximately 5.4 Mt (6 million st) of recoverable coal. SUFCo has been a world leader in productivity for a

Jan 1, 2003

By A. J. Thompson

The Metropolitan Transportation Authority (MTA) East Side Access project (ESA) will, when it is complete, provide a new link to the east side of Manhattan from Long Island, NY that, linked with the Second Ave. Subway currently under construction, will assist in relieving overcrowding at Penn Station as well as the Lexington Ave. subway. ESA will bring Long Island Railroad (LIRR) directly from Long Island into a new station located 37 m (120 ft) beneath the existing Grand Central Terminal (GCT) located in the heart of Manhattan. It will connect the LIRR?s mainline tracks in Queens, via the existing 63rd Street Tunnel under the East River, to a new terminal constructed within, and beneath, the historic Grand Central Terminal.

Jan 1, 2012

By Fred C. Bond

Any improvement in the accuracy of commercial comminution calculations under the Third Theory must be accomplished either by increased precision in energy input measurements, or by a better evaluation of the total new crack length produced, as indicated by the feed and product size distributions. Since at the present time feed and product sizes are approximated solely by the microns 80% passes, the most promising opportunity for increased accuracy lies in consideration of their plotted size distribution characteristics. This paper shows how more accuracy can be obtained over an increased range of feed and product sizes from size distribution studies.

Jan 1, 1962

By Lawrence Williamson, Randall J. Essex, David P. Field

As part of a $2.2 Billion bridge project that will link Indiana and Kentucky, an interchange project northeast of Louisville will require the mining of a 6-lane tunnel system about 2,000 ft long in order to cross beneath the historic Drumanard Estate. This paper will discuss preliminary engineering that has been undertaken to compare two-bore and three-bore layouts, the planning of an exploratory tunnel facility, and the potential for including a test chamber to investigate the ability of high capacity roadheaders to mine the 22,000 psi limestones.

Jan 1, 2005

By M. Schafer

The 6-m- (20-ft-) diameter cast-in-place tunnel lining for Phase 3 of the Mill Creek Tunnel (MCT3) has been completed. This article summarizes aspects of liner design and ad-dresses the construction approach in placing the liner in areas of tunnel that experienced crown overbreak. Tunnel lining production rates, installation procedures and form buoyancies experienced during concrete placement will also be presented. The Mill Creek Phase 3 tunnel (MCT-3) is expected to be completed this year. It is one of the largest tunneling projects undertaken by the Northeast Ohio Regional Sewer District (NEORSD) to date. The tunnel horizon is situated within the Devonian Chagrin Shale rock formation at an average depth of 85 m (280 ft). The tunnel was excavated using a two-pass method. A full face, fully shielded, Robbins 7.2-m- (23.8-ft-) diameter tunnel boring machine (TBM) was used to excavate approximately 4,500 m (15,000 ft) of tunnel and facilitate installation of initial supports (first pass). The final lining (second pass) consists of 305-mm- (12-in.-) thick cast-in-place reinforced concrete and integral low flow channel. Seven shafts were constructed on the project. The excavation of the tunnel commenced at Shaft 14 and proceeded down grade to Shaft 9, the terminus shaft. Because of the presence of overbreak in the tunnel crown, measures were required to support the form and counteract the effects of buoyancy during concrete placement.

Jan 1, 2008

By M. A. Giralico

Solvent Extraction (SX) technology has undergone significant refinements including outright process changes to achieve greater copper production rates with lower organic entrainment levels. LIGHTNIN has completed a detailed study aimed at improving on the conventional Holmes & Narver and Davy Power Gas type impeller designs1 by optimizing the mixing through the use of high efficiency pumper turbines instead of making system changes as others are doing. Since each individual installation requires a different design head and flow, LIGHTNIN has developed the R320 "family" of high efficiency, curved blade pumper turbines. These impellers are designed to maximize head and flow while reducing entrainment through lower power consumption, less shear generation and turbulence, elimination of air incorporation, production of the optimum droplet distribution, and lower tip speeds. These improvements also maintain the required mass transfer and copper recovery of the traditional impeller designs. The R320 impeller benefits have been quantified using Laser Doppler Velocimetry (LDV) and proven in multiple domestic and foreign installations at flow rates exceeding 15,000 GPM. Design comparisons of this improved impeller type versus traditional technology impellers in head, flow, power and entrainment are presented for review. In addition, the inherent benefits of axial flow, high efficiency impellers like the A3 1 0 and A6000 in auxiliary mix chambers will be discussed. The high flow, low shear characteristics of these patented impellers provide the necessary dispersion stability for mass transfer while speeding phase disengagement in the settlers due to low power and low shear input.

Jan 1, 1995

By D. Bristow, D. Baker, K. Awuah-Offei, A. ur Rehman

While a body of work exists on intelligent systems for guiding occupants out of buildings during an emergency, the problem of guiding miners out of a mine during an underground emergency has not been explored. Underground evacuation fundamentally differs from building evacuation because of differences in the regulatory regime and uncertainty regarding the number of occupants. The potential for implementing an intelligent miner guidance system is buttressed by the fact that miner tracking systems, along with communication and sensor networks, already exist in underground mines. This work presents a method based on a local positioning system, in the form of a network of “nodes” at major “intersections,” which can then be used to guide miners to safety. We have developed a path-planning algorithm, based on Dijkstra’s algorithm and the local positioning system that can provide miners with the optimal escape path in an emergency. The algorithm is validated with scenarios at the Missouri University of Science & Technology Experimental Mine demonstrating the potential to include smart technology in mine emergency management and response planning. INTRODUCTION Underground mines are hazardous environments with a higher than usual risk of safety emergencies where miners have to evacuate the mine to save their lives. Mines have always trained miners to evacuate or shelter-in-place in minimum time. Jalali and Norrozi (2009) opined that the three major components that help miners in case of emergency are pre-planned optimal escape routes, decreasing delays, and improving the education of miners. In fact, Goodman and Kissel (1990) suggested that fatalities arising from mine accidents could be reduced by 50% just by decreasing delays in finding the pathways in case of emergency. The proposed work can assist miners in finding escapeways quickly in case of emergency. It is very important to have a pre-planned evacuation strategy that is clearly communicated to miners to ensure the safety of all (Conti, Chasko & Wiehagen, 2005).

Jan 1, 2019

By A. A. Wallach

During the early design stages of the San Manuel Concentrator, numerous questions were raised concerning the required slope for tailings pipelines. The tailings disposal area which had been selected was so situated, that an average down-slope of 5% existed. A gravity tailings disposal system was to be designed and it was necessary to determine the optimum pipeline slope for design purposes. This information was also necessary to determine the life of the available disposal areas before tailings pumping would be required. At approximately the same time as this problem arose, it was reported that a concentrator in the southwest was having considerable operational difficulties due to periodic plugging of tailings lines. These factors combined made it seem desirable to conduct some sort of test work which might give information concerning the flow characteristics of the tailings to be produced, from the San Manuel Concentrator. It was felt that the maximum information could be obtained if a tailings line could be erected which would allow for varying slopes, varying heads and accurate measurement of pulp velocity. A five-foot Denver Agitator was installed on a bank overlooking a cut for a rail- road track. Approximately 160 feet for new &-inch pipeline with victaulic connections was installed on low trestles along the track, with provisions made for varying the slope of the line by use of accurately constructed sets of shims, A valve discharge was installed on the tank so agitated pulp could be run into a standpipe at controlled volumes. This standpipe was 10 inches in diameter and approximately 5 feet high. A 4-inch nipple welded into the side of the standpipe approximately one inch from the bottom was connected to the 4-inch pipeline. At the discharge end of the 4-inch pipeline a launder arrangement was so constructed that the entire discharge could run into a pump sump or into 50-gallon measuring vessels. In normal operation the flow was from the agitator to the standpipe through the pipeline into the pump sump and from there pumped back to the agitator tank.

Jan 1, 1958