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By Hui Lu

The structural changes in solutionized AA2618 during natural aging and their effects on subsequent artificial aging were investigated by hardness measurements, X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. The changes in lattice parameter and hardness during natural aging indicate that copper-enriched clusters form in the earliest stage, followed by the formation of magnesium-enriched clusters and coppermagnesium co-clusters. Prior natural aging consistently weakened the hardening during subsequent artificial aging at 180, 200 and 230 °C but had no effects on artificial aging at 150 °C. The decreased age hardening was attributed to the reversion of small clusters/zones that formed during prior natural aging. The lattice parameter exhibited erratic changes with increasing artificial aging time, reflecting the complex sequence of the reversion and precipitation.

Jan 1, 2006

The 21st Annual American Mining Hall of Fame Awards Banquet sponsored by the Mining Foundation of the Southwest will be held at the Sheraton Tucson Hotel in Tucson, AZ on Saturday, Dec. 6, 2003. This year’s inductee, guest of honor and featured speaker at the banquet will be Thomas J. O’Neil, recently retired president and chief operating officer of Cleveland Cliffs Mining. Prior to Cliffs, O’Neil spent 10 years with Cyprus Minerals. He was also professor and head of the Department of Mining and Geological Engineering at the University of Arizona. As representatives of mining heritage, the Hall of Fame will induct James Boyd and Thomas F. Walsh. Walsh discovered a rich gold telluride vein in Ouray, CO, which became the Camp Bird gold mine. Boyd was a former director of the U.S. Bureau of Mines, vice president of Kennecott Copper and later president of Copper Range.

Jan 1, 2003

By Sean Gallagher, Gene Wilson, Christopher Mark, Craig S. Compton, Gregory M. Molinda

Falls of small pieces of rock from between roof bolts continue to cause fatalities and to injure hundreds of coal miners each year. Roof screen is the most effective way to prevent these incidents, but some mines are reluctant to use it because they believe installing screen can be awkward, expensive and time-consuming. The most common type of roof bolting machine used in mines today is the dual boom, outside-controlled roof bolter. Mines who install roof screen using these machines have developed some machine modifications and techniques to ease roof screen installation. This paper describes some successful techniques and machine modifications that are being used in productive mines to assist with roof screen installation. Since the material handling involved with roof screen installation can expose miners to an increased risk of musculoskeletal injuries, the National Institute for Occupational Safety and Health (NIOSH) ergonomists, designed machine modifications and implemented a series of tests to evaluate roof screen handling procedures for outside-controlled, dual boom roof bolting machines. Roof screen installation can also have a positive economic impact on a mine by reducing the cost of injuries, workers’ compensation, required spot or re-bolting, and clean-up of long term travel and belt entries.

By Sutham Niyomwas

The Fe-TiC composite powder was synthesized in situ by carbothermal reduction of ilmenite. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of the reaction temperature (1300 °C - 1500°C) and milling time of precursors on the Fe-TiC conversion and powder morphologies were investigated using XRD and SEM method. The synthesized products showed that composite with iron matrix and titanium carbide as a reinforced phase was formed.

Jan 1, 2006

By H. J. McQueen

ORDER OF PRESENTATION ?INTRODUCTION TO THE VICTORIA BRIDGE ?REASONS FOR A BRIDGE AT MONTREAL ?RAILROAD BRIDGE REQUIREMENTS ?IRON PRODUCTION CANADA / WORLD AL ?METALLURGICAL INDUSTRY CANADA ?FAIRBAIRN, STEPHENSON SHIP PLATE-RIB BOX GIRDER ?VICTORIA BRIDGE (PREFABRICATED BRITAIN) ?IRON ORE SITUATION THE VICTORIA BRIDGE 1859, TUBULAR -WROUGHT IRON* 1898, TRUSS ?STEEL* (*HOT RIVETED) 1957, SPUR, LIFT SPANS ??DUCTILE WROUGHT IRON WITHSTANDS FATIGUE ?TO KEEP THE TRAINS ON TIME & ON TRACK? ??IMMOVABLE SHARP PIERS SPLIT ?THE IRRESISTIBLE ICE, STOPPED CITY FLOODS? ? ?********* ??111 YEARS-YOUNG STEEL TRUSS, (1898): ?STILL VITAL SEA-T0-SEA RAIL LINK? ? ?********* ??51 YEARS HAVE PASSED SINCE SEAWAY (1958) ?SWITCHED BRIDGE INTO DOUBLE LIFT SPANS?

May 1, 2011

By G Williams

Discussing equipment, systems of work, the need for updated programmes of local seismic exploration, and developments within the South Wales coalfield.

Jan 1, 1993

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the mining laws of British Honduras has been prepared from the best available information in Washington and is released subject to amplification or correction, if necessary, by United States foreign-service officers. INTRODUCTION The mining law governing all mineral substances other than oil is ordinance No. 7 of 1927 (Minerals Ordinance, 1927), passed by the Legislative Council on March 25, 1927. The accompanying regulations, No. 3 of 1932 (General Minerals Regulations, 1932), made under the authority of section 66 of the minerals ordinance, were made by the Governor in Council on December 23, 1931.

Jan 1, 1934

By D. M. A. Flight, P. M. Green, J. A. Plant, P. R. Simpson

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. The British Geological Survey's regional geochemical database is used to identify the patterns associated with the various mineral deposit types and to examine the extent to which their distribution reflects the presence of long-lived metallogenic provinces in the crust. Image analysis provides new insights into the setting of the mineralisation, geochemical constraints on tectonic models of Caledonide evolution and evidence for terrane amalgamation and large-scale processes. There is evidence that much of the mineralisation reflects the presence of long-lived provinces with a distinctive geochemistry reflecting their origins as zones of crustal extension. In the case of the Middle-Upper Dalradiam sedex deposits, the relationship between geochemistry and tectonic setting is direct. In other cases, rocks deposited in extensional zones appear to have acted as reservoirs of ore-forming elements which were further concentrated during later events

Jun 19, 1905

By Jeon Jeon, Yong-Kun Choi, Chung-In Lee, Yong-Hun Jong, Hag-Soo Kim

In this study, a computer program to design tunnel blasting pattern has been developed. The program consists of two parts; one is for tunnel blasting pattern design and the other is for blasting modeling to estimate the peak particle velocity, the distribution of fragmentation and the excavation damage zone. We modified the design method of tunnel blasting pattern suggested by Langefors because it provided undesirable pattern in blasting practices such as considerably large center cut and too large burden for Vcut as drilling length increased. As a result, the burden and spacing were reduced to practically appropriate amounts. In addition, the correlation between rock mass rate, RMR, and rock constant in blasting, c, was analyzed based on the data collected from twenty three tests of tunnel blasting. It was concluded that the correlation between them was fairly good enough to be applied in cut design. In order to check the validity of the modified methods and their practical applicability, test blasting was carried out at two different tunnel construction sites in Korea. The results were satisfactory in that the average rate of advance was 90% and the overbreak did not cause additional support. Futhermore, the developed program is capable of estimating peak particle velocity by using (a) the existing vibration equations, (b) the vibration equation obtained by test blasting to check out the practical applicability of the designed blasting pattern. Feedback is implemented into the program to adjust the designed blasting pattern and control the vibration.

Jan 1, 2005

By Yuanbo Zhang

Zinc leach residues produced by hydrometallurgical zinc plants contain many valuable elements (zinc, iron, lead, gallium, indium silver, etc), while they have not been utilized effectively hitherto. In this paper, a new process of flotation-reduction roasting-magnetic separation to recover these valuable elements from zinc leach residues is developed on a basis of mineralogy investigations of them. The results show that silver concentrate with grade of 4321.6 g/t and recovery of 80.69% have been obtained, using 1750 g/t Na2S as conditioner, 750 g/t ammonium dibutyl dithiophosphate and SN-9 (assistant collector) as combined collector and 100 g/t terpenic oil as frother, if zinc leach residues with 523 g/t silver are floated at pH = 5.0. When the flotation tailings are subjected to reduction roasting at 1100? for 2 h, the volatilizations of zinc, lead and indium are over 96%. After roasted products are treated by wet-grinding and magnetic separation, the grade of gallium and gallium in the concentrates achieved respectively reaches 1805 g/t and 1536g/t, and the recovery of them is high to 94.67% and 93.20%, respectively.

Jan 1, 2006

By G. S. Takenaka

When Bridger Coal Company transformed their operations from surface mining to an underground longwall operation their plans included not only the addition of new mining equipment but also surface fans for a blowing (supply) air ventilation system. The original system concept included a propane gas fired air heater to preheat the intake air during cold weather and a dual parallel fan and duct system. One fan operated to ventilate the mine while the other fan was for stand-by emergency operation. Equipment proposals were submitted in March, 2005 based on the dual parallel fan system. Discussions conducted during the equipment selection process revealed that several alternative system design concepts were available. The alternative concepts included innovation features that not only saved space and cost but also reduced operating expense as well. Many of the features were incorporated into the final design of the system. A comparison of the original system concept and final installation design are presented in the paper in addition to details of the features and the derived benefits.

Jan 1, 2009

By Norman A. Jull

"IntroductionThe scope of this paper is intended to deal mainly with cyclones in grinding circuits. However, the section on Cyclone Equipment, contains more general descriptions, to cover most of the cyclones used in mineral separation plants.Cyclones as heavy media separation vessels are discussed by Mark Freberg (this volume). Their use in tailings deslirning is discussed by P.C. Lighthall, eta/. (this volume).Cyclone EquipmentCyclone TerminologyApexObviously, the apex of a cone is the smallest end. However, with cyclones the term is usually used for the fitting which is attached there to control discharge of the underflow stream.Note that the cyclone need not be so mounted that the apex is the lowest point, although that is the most common method. Keeping the apex below the rest of the cyclone helps avoid plugging when the underflow contains very large particles and the tonnage of underflow solids can fluctuate.Various devices for adjusting apex diameter or otherwise controlling the underflow are discussed later under ""Cyclone Construction"".BypassingThe transport of a portion of feed slurry directly to underflow so that classification is bypassed by that portion of feed.This action is fundamental in any hydraulic classification, whether gravity or centrifugal, because the large particles going to underflow have some void volume between them, which remains filled with feed slurry.D50By definition, D50 is that particle size which has an equal probability of going to overflow or to underflow.It is calculated by drawing a curve of recovery vs particle size and noting the size at which 500Jo recovery occurs.This may be done equally with corrected or with gross recovery (see below) and the resulting value should therefore be identified as d50c (corrected d50) or as d500 (gross d50).Note also that it is common in industry practice to plot size analysis data on the retained size rather than on the average of passing and retained (the middle of the size band). To portray sizing alone it makes no difference, but to read a D50 value off a curve of corrected or gross recoveries, it is essential to plot those values on the average size of each band."

Jan 1, 1989

By W. James Marold

The New Croton Aqueduct (NCA) was the first major water supply tunnel for New York City. The 50-km (31-mi) long tunnel has 33 open shafts 6 m (20 ft) to 121 m (397 ft) deep. The tunnel and shafts are lined with brick and mortar, with cast iron lining and pressure covers in six pressurized shafts. Details of the 1895 construction are provided and compared to modern construction techniques. The paper provides rehabilitation techniques for the shafts and pressure covers, including grouting, epoxy lining, temporary bulkhead design and installation and placement of tremie concrete 98 m (320ft) below the water level in a 122 m (400ft)deep shaft using a Remote Operated Vehicle (ROV) to monitor the placement.

Jan 1, 2008

By H Saw, M Cordova

Cemented rock fill (CRF) is often used to support open stope voids. This allows for the full recovery of ore while achieving global mine stability. In such cases, the exposed CRF masses require adequate compressive strength and stiffness to resist the forces and limit the displacement associated with movements in the rock mass surrounding the excavations. The CRF material preparation often involves the use of large particles, either from crushed rock or development mining waste. This means that conventional laboratory samples cannot be readily used to determine the laboratory strength. Consequently, a research project was undertaken to determine the influence of sample size on uniaxial compressive strength. This paper presents the results from CRF samples that were prepared using the same mix design and then cast into moulds with diameters of 150, 240, 300 and 400 mm. The laboratory testing also allowed a better understanding of the effect of particle size distribution upon the overall strength of a rock fill mass. The laboratory results were compared to a database of large-scale results from the testing of fill masses from a number of mine sites.CITATION:Cordova, M, Saw, H and Villaescusa, E, 2016. Laboratory testing of cemented rock fill for open stope support, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 755–762 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J. Kirsch

Keywords: Pyrometallurgy, pneumatic transport, pneumatic transport Dense-phase pneumatic injection has begun to replace more traditional furnace-feeding systems. The paper describes the technology as it is applied to processes where the back pressure at the point of injection is greater than 50 kPaG. It reviews earlier systems of injection and more recent developments that address concerns for instantaneous control in modern smelters. The new technologies fall into two groups, (1) modified pressure-difference control (sub-divided into simple and complex) and (2) mechanical-feeder-based control. Features of current injection systems include feed splitting in two forms, passive and active, and co-current injection.

Jan 1, 2006

By I Lourel

In evaluating the installation of an in-pit crushing and conveying (IPCC) system for any mine, a number of options are available for each of the dig side, transport and dump side operations. Some of them are moreappropriate than others; given the pit arrangement, the material being handled and the rates at which it needs to be moved. This paper seeks to document the options that might be employed, and to rank them in terms of their applicability at any mine and their practicality overall, with a view to nominating those that would be most suitable for further study.

Jan 1, 2009

By Paul M. Ambrose

Overall the domestic abrasives industry had one of its best years in 1965. Production and value of all commodities increased over that of 1964 which also was a good year. Production of tripoli that was down in the previous year rebounded and production from two new mines was reported. Plant capacities for production of silicon carbide and fused crude aluminum oxide and production from plants in the United States and Canada increased, but demand was high and yearend stocks were less than at the end of 1964. Foreign Trade.-Increases in value of most imports of abrasive materials in 1965 were offset by a decrease in the value of imported industrial diamond. Production of fused aluminum oxide and silicon car-bide in the United States and Canada and imports of these commodities into the United States increased, but combined exports of finished grain of these materials was virtually unchanged from the previous year.

Jan 1, 1966

By Slavoljub D. Maksimovic

The Bureau of Mines, through a memorandum of agreement with the State of Ohio, tested a method of constructing seals in abandoned mine openings in Ohio by means of pneumatic stowing of crushed limestone and gravel with sand. A total of five openings and one shaft were back-filled. Pneumatic stowing uses compressed air to convey material through a pipeline and into the mine opening. The stowing equipment consists of a power supply, a blower, a feeder to inject the material into the pipeline through an airlock, and a nozzle for directing the placement. Material is ejected from the nozzle at high velocity, creating a high-compaction fill upon impact. Well-graded aggregate up to 2 inches in diameter and having sufficient fines is used as fill. The stowing method is safer and faster than conventional methods, is cost competitive, prevents trespass into abandoned mine openings, and eliminates or reduces the exposure of workers to possible hazards since the discharge nozzle can be kept at the mouth of the opening. The equipment is mobile, and, with some modification, the technique could be widely used for sealing abandoned and active mine openings, even in remote locations and during severe weather conditions.

Jan 1, 1982

By Meagan S. Boltz

From October 2000 to April 2001 a local array of fourteen seismograph stations was deployed at the Trail Mountain Mine (TMM), an underground coal mine in Emery County, Utah, to locate mining-induced seismicity (MIS). Original analysis of the data provided epicentral locations that coincided closely with the active longwall panel. The original analysis yielded poor quality hypocenters, however, preventing a useful relation from being made between mining activity and the event depths. For the original analysis, only stations at elevations above mine level were used for locating MIS. As a result, P- and S-arrival times from four of the stations in the local array were not used: an inmine station and three stations at elevations below mine level. This study compares mine workings and active mining to a revised TMM dataset that included P- and S-arrival times from the lower elevation stations that were not used in the previous study. In the revised locations, a modified master event methodology was used to calculate station delays. These station delays correct for errors in the shallow layers of the velocity model. The resulting hypocentral locations have improved depth resolution, determined by a lower root mean square (RMS) for the locations, compared to the original study. Most of the events occur in the roof of the mine and follow the longwall panel. When located using the velocity model determined in the original study, the elevations of the events increase as the longwall panel progresses. One possible explanation for the elevation increase is that it may be related to geology or the caving process. As presented here, a 10% decrease in the shallow velocity structure results in a more plausible location for the hypocenters. Consequently, it is hypothesized that progressive development of the TMM longwall panel(s) may have resulted in a progressive change in the velocity model.

Jan 1, 2012

By Roy C. Fedotoff, Jon Hurt, Gregg Sherry, Gilbert Tang

The 1,380 m (4,200 ft) long New Crystal Springs Bypass (Polhemus)Tunnel (NCSBT) will replace the existing Crystal Springs Bypass Pipeline. This tunnel project is part of the SFPUC’s $4.3 billion capital improvement program to repair and seismically upgrade their aging pipelines, tunnels, reservoirs and dams that provide drinking water to more than 2.4 million customers in the San Francisco Bay Area. This paper describes the development of the tunnel alignment and design, and the complex ground conditions of the Franciscan Mélange. Of particular interest is the challenge of tunneling with a possible downhill grade of 3%, a rigorous environmental process and incorporating the lessons learned from 1960s construction of the adjoining Crystal Springs Bypass Tunnel.

Jan 1, 2007