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By T. E. Wilson

An exploration bore core sample of coal ought to be reduced from its original cylindrical form to a particle size distribution and particle composition that reflects, insofar as possible, a process stream of? raw? coal it represents. Often, coal cores are reduced with a laboratory crushing machine, the product of which may not match the raw coal size distribution or size fraction composition. This study employs drop-shatter impact breakage followed by dry batch tumbling in a steel cylinder rotated about its transverse axis in order to characterize the core material in terms of first-order and zeroth-order breakage rate constants. These are indices of the propensity of the coal to degrade during excavation and handling. Initial drop-shatter and dry tumbling tests were done with synthetic cores, to reduce material variables and . conserve difficult-to-obtain coal cores.? Cores of three different coal beds --Illinois No.6, Upper Freeport, and Pocahontas No. 5 -were subjected to drop-shatter and dry batch tumbling tests to determine breakage response. Comparison of coal preparation plant feed with a crushed bore core and a bore core prepared by drop-shatter and tumbling (all from the same Illinois No.6 coal mining property) indicated that the size distribution and size fraction composition of the drop-shattered/tumbled core more closely resembled the plant feed than the crushed core.

Jan 1, 1998

By V. V. Satya Prasad, A. Sambasiva Rao

Electroslag melting technologies have recently been developed for recycling light scrap of valuable metals and alloys such as superalloys and oxygen free high conductivity (OFHC) copper at Defence Metallurgical Research Laboratory (DMRL), Hyderabad. Conventionally, electroslag melting processes use consumable electrodes. Because of the difficulty in compaction of scrap into a consumable electrode of satisfactory quality, non-consumable electrodes such as graphite and water-cooled copper have been designed. Electroslag remelting using a water-cooled non-consumable electrode was developed to melt scrap of a nickel base superalloy. Sound ingots with smooth surface finish and properties comparable to vacuum melted superalloys could. be obtained from scrap using this process. A modified electroslag crucible melting process using graphite crucible and graphite electrode was developed for recycling OFHC copper scrap. Copper ingots with less than 10 ppm oxygen and electrical conductivity"" 100% IACS could be produced. The same process was also utilized to produce copper-based alloys such as copper-chromium and copper-titanium starting from copper scrap.

Jan 1, 2000

By Phil W. Welch

At first glance, the similarity between the fine grinding of cement clinker and coarse grinding done in other mineral processing industries may seem remote. However, it is interesting to note that the mill discharge fineness of cement clinker is only 70 to 90% passing 100 mesh and quite comparable to other mineral processing grinds. There is however, a greater dependence of the mill on the air separator in the finish grinding of cement clinker than in other mineral processing industries which explains why a technique to guage the balance between a mill and separator first began in the cement industry. (1) More recently an adaptation of this technique has shown its application to the processing of phosphate rock and is the central topic of this paper. First, an explanation of work done with fine grinding cement circuits seems appropriate together with a few general comments regarding cement. When unground or partially ground cement clinker enters a finish grinding mill, it is subjected to mechanical forces of impact and attrition which gradually reduce it to a range of sizes characteristic of finish cement. That is, a range of approximately 1 to 125 microns. The large proportion of superfine particles relative to the coarse and intermediate size particles is typical of portland cement particle size distribution. It accounts for the workability characteristics of plastic concrete and the early strength development of concrete which is so necessary to its successful use as a construction material. For this reason It is quite evident from quality control tests when a shortage of superfines exists.

Jan 1, 1975

By Sean Cassady, Jason Liu, Sanja Zlatanic, Taehyun Moon, Chris Devery

"For the Hollywood International Airport Runway Expansion Project at Fort Lauderdale, Florida, the structural fire durability analysis was completed for a series of tunnels formed by roadway and railroad cells located under the runway structure. A systematic design approach was developed to mitigate structural damage during a fire event and arrive at a practical method to structural fire engineering that is compliant to NFPA 502. To ensure the NFPA 502 requirements are satisfied, the performance based approach was implemented and the engineering analyses were performed for the adopted design fire event. The analyses considered the facility’s unique features including its fire safety systems to determine applicable design fire curves for structural durability analyses. The paper also outlines the process of defining the project specific fire curves for a specific design fire scenario and summarizes the results of heat transfer and structural fire durability analyses. This approach was aimed to assist the owner and Authority Having Jurisdiction to achieve practical decisions to the tunnel facility fireproofing.INTRODUCTIONFort Lauderdale–Hollywood International Airport (FLL) in Broward County, Florida is a major hub facility serving more than 23 million passengers annually. As part of the Airport Expansion Program, the South Runway (9R-27L) Expansion project aimed to meet ever increasing service demands via an increase to runway lengths. This necessitated the placement of one of the reconstructed runways on bridge structures over the existing U.S. Route 1 (US 1), a major north–south U.S. Highway that serves the East Coast of the United States, and the Florida East Coast (FEC) Railway, thus effectively creating multiple tunnel cells beneath the subject runway. For this project, HNTB suggested a tunnel fire damage mitigation system that would protect the runway major structural elements from the design fire event that may happen within the tunnel cells. This paper addresses the issues related to the fire event originating within the tunnel encompassing the US1 highway only, and deals with requirements of NFPA 502 [5] exclusively. Therefore, while approaching the structural fire protection issues for the specific tunnel cells beneath the runway structure, the requirements of the American National Standard NFPA 502 (Standard for Road Tunnels, Bridges, and Other Limited Access Highways, 2008 edition) were followed. Per this standard, regardless of tunnel length, all primary structural concrete and steel elements shall be protected in order to:"

Jan 1, 2016

By Eric Nelson

The paper point out the structural openings and the localization of ore bodies. Structural openings in rocks constitute the primary permeability network for the formation of most hydrothermal ore deposits. The distribution, geometry, density, and orientation of ore bodies in structural openings are controlled by two primary factors: the far and near field stresses and the mechanical properties of rock. When stress controls the orientation and kinematics of faults and fractures in the absence of pre-existing weaknesses, ore shoot orientation is perpendicular to the fault slip vector and can be predicted by kinematic analysis. However, when structural openings form along pre-existing weaknesses, ore shoot orientation cannot always be predicted by kinematic analysis. Because we can classify ore bodies based on the types of geological structures discussed above and the variations that naturally occur from material property heterogeneity, exploration for hydrothermal ore deposits should include analysis of geologic structure and evolution, rheological variations, pre-existing weakness, and fault kinematics to evaluate structuralcontrols on localization of ore bodies.

Apr 22, 2003

By Peter M. Fozzard

The San Bartolomt silver deposit was discovered by a United Nations team of geologists working with a counter- part team of staff of the Ecuadorian Government's General Directorate of Geology and Mines (DGGM). The Phase I project over five areas of operation during which this discovery was made was financed through a United Nations Development Program contribution of $860,000 and an Ecuadorian Government participation of about $680,000 equivalent. Existence of mineralization at San Bartolomé was first recognized in 1966 when a reconnaissance geochemical stream-sediment program was carried out over a 10 500 km2 (4,054 sq mile) area centered around the city of Cuenca in southern Ecuador. Over the course of this project more than 10,000 samples of stream-sediment, soil, and rock materials were collected. Average costs per sample were $10.00, as follows: collection, $5; sample preparation, $1.60; assay work, $3.40. Initially in the program (1965-1966) sediments were collected along all motorable roads and tracks. Routine analyses, originally by colorimetry and later by AAS, were for Cu, Pb, Zn and occasionally As, Ni, and Co. Discovery geochemical samples from the San Bartolomé drainage area were among the first to be taken in 1965. As luck would have it, the road along which this traverse was taken passes only some 100 m (328 ft) downstream from the mineralized suboutcrop. The relevant two streams sampled are of inconsequential size, some 1 m (3.3 ft) in width, with a limited flow volume throughout the year. Original anomalies were recognized through cold-extractable Cu/Zn analyses. The pH of all river waters was also recorded at sample sites. Resampling the discovery sediments when AAS became available showed total extractable values of between 150 ppm-300 ppm Zn, 550 ppm Pb, and 10 ppm Ag. In 1967 the first followup was by rough-and-ready means. Dithizone field-kits (THM) were used to rapidly test soils from the surrounding area. The area has no outcrop. This work allowed the definition of an area of interest of some 2 km (1.2 miles) x 500 m (1640 ft). Six approximately 1 km (0.6 mile) to 1.5 km (0.9 miles) lines spaced at approximate 250 m (820 ft) intervals were established and used for IP surveys and soil sampling at 50 m (164 ft) intervals. Where one of the lines crossed the westernmost geochemical discovery creek a first-priority geophysical anomaly coincided with a major Zn/Pb (and later Ag) soil anomaly. A pit was sunk and encountered mineralized vein material at a depth of 1.5 m (5 ft). This lucky glory hole confirmed the geochemical discovery and prompted systematic followup. Immediately, costeaning of the west bank of the discovery creek, the Quebrada Ocashuaico, was carried out and exposed weathered and leached mineralization. Nearly 100 mineralized veinlets ranging in thickness from 0.5 cm (0.2 in.) to 8 cm (3 in.) were exposed across the 180 m (59 1 ft) costean. Sixty mineralized veinlets were determined over a 90 m (295 ft) wide zone. Sampling delineated minable widths averaging between 0.16 and 0.31 kg/t (5 and 10 oz per st) Ag with associated copper (very sporadic) lead and zinc. Over the period 1968- 1972 a considerable amount of detailed work was completed: detailed IP, EM Turam, magnetic and mise-a-la-masse geophysics, very detailed soil- sampling, trenching, drilling and glory-hole drifting, and cross-cutting. Numerous problems were encountered: the area was found to be a most difficult geoelectrical target; zero outcrop; pyrite (nonargentiferous zones) associated with faulting; mineralized groundwater; extensive clay development; loss of diamond drill-core, and no two-dimensional surface information. As the program developed the complexity of the structure was slowly unravelled, using a degree of good guesswork. Apart from photogeological and ground geological mapping at various scales, the following

Jan 1, 1985

By D Maconochie, S Pradhan, M Reed

The Waterview Connection will provide a high-quality strategic alternative to State Highway One and complete Auckland’s Western Ring Route connecting State Highways 20 and 16. The project includes twin three-lane motorway tunnels 2.4 km long and 13.1 m internal diameter (ID). The tunnel construction started in November 2013 using the tenth largest earth pressure balance (EPB) tunnel boring machine (TBM) in the world. The tunnels will pass beneath urban and greenfield areas as well as a major local arterial road. The project is being delivered by an alliance of constructors, designers and the New Zealand Transport Agency. This paper describes some of the key innovative and cost saving design solutions that have been achieved through collaboration in the alliance environment with the construction team, owner’s verifier, the segmental lining precast suballiance and the M&E suballiance for the underground works. The key design elements of the tunnel comprise a three-lane roadway, invert culvert and backfill, precast segmental lining, sixteen mined cross passages including a low point sump cross passage and steel segments for opening to the cross passages. This paper reviews interdisciplinary design integration and the economies achieved in the permanent works tunnel lining design, including reduction in lining thickness and optimising reinforcement, cross passage separation of 150 m, efficient design of the invert culvert and backfill design, main drainage pipe and low point sump. The paper also describes the attributes of the TBM and the invert culvert construction methodology.CITATION:Pradhan, S, Maconochie, D and Reed, M, 2014. Tunnel design in an alliance for Waterview Connection, New Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 425–430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By H. Kenworthy

Sulfide-ore concentrates containing cobalt, nickel, copper, lead, and iron from the operations of the National Lead Co. at. Fredericktown, Mo., were treated successfully on a laboratory scale to recover more than 90 percent of the cobalt, nickel, and copper. A cobalt -nickel-bearing, lead-copper matte., produced by the St. Joseph Lead Co. at Herculaneum, Mo., was treated to produce a lead-zinc fume, a copper sulfide concentrate, and a cobalt nickel-iron product, netting a recovery of over 75 percent of the cobalt and about 90 percent of the nickel and copper. National Lead Co. bulk concentrates were chlorinated with gaseous chlorine to form anhydrous metal chlorides and sulfur chlorides, sulfur chlorides were recovered by distillation, a high percentage of the ferric chloride was converted to ferric oxide, and the chlorinated residual metals were extracted with water. Metal ions were removed from leach liquors by pH-controlled fractional precipitation as hydroxides. Cobalt solutions "were prepared from cobaltic hydroxide, and procedures were developed to remove contaminating metal ions. Purified cobalt solutions were employed as electrolytes for deposition of high-purity cobalt.

Jan 1, 1953

By Robert E. Barieau

In the design of plants to separate helium from natural gas , it is necessary to estimate the enthalpies of the various streams at various positions in the process . This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities . The minimum information required for developing an enthalpy diagram is presented , and the relative merits of the various methods are discussed . It is concluded that methods that require no mass flow rate or energy measurements are to be preferred .

Jan 1, 1965

By Winfried Rosenstock, Carlos Orlandi

Along the Pacific West coast of Latin America there are several large operations of metal mining activities. To mention only a few: Chuquicamata in Northern Chile moving daily approximately one million t of copper ore and waste, Cerro Verde near Arequipa in Peru, or lanaccocia. Apart from the coal deposits in north-east Columbia it is mainly to deal with metal-mining, which has due to geographical reasons relatively high cash-cost. This sector of mining is traditionally severely depending on the world-market.There are reasons to believe that the world-market will remain on a low price level and some analysts predict that in general the price-level will continue on low basis for the next decade. The cash-cost factor becomes therefore even more important as it already is. The goldprice development during the year 1999 illuminates that market changes can quickly lead to a severe crisis which forces the shutdown of mines with cash-costs close to or above the present market price per ounce. The breakdown of the cash-cost shows, however, that there are ways to overcome even the crisis like it struck the low-grade open pit goldmines around the world. Especially hitherto the “Electronic Option” is the only solution as the possible reduction using advanced technology based on the application of electronic detonating systems and newly developed special ignition procedures. The electronic option will lead to tremendous cost reductions similar to the results of research operations Thiess Contractors, Brisbane, Australia have carried out in Australia in 1998 and 1999. The electronic option allows a comprehensive integration of side effects of the blasting process which in the past could not have been achieved so far. Electronic initiation can achieve secondary effects which have an additional and positive impact on the level of costs. Appropriate application can enhance the production of material which will reduce the primary crusher costs or even make a primary crusher operation obsolete.

Jan 1, 2000

By K. Scalise, M. Teixeira, K. C. Kocsis, J. Parrish

"This paper aims to introduce and discuss a newly developed algorithm, which can be uploaded on smart watches and other mobile devices to inform and protect underground personnel working in hot and humid environments. Using this algorithm, the metabolic rate (M) of a worker can be determined in “real-time”. In addition, besides warning signs and alarm signals emitted by the smart watch, the algorithm has the ability to determine work-rest time periods based on the worker’s physiological parameters (e.g. age, height, weight, gender) and the climatic parameters (Td, Tw, flow velocity). This paper also investigates whether a re-designed auxiliary ventilation system can provide appropriate work conditions in the production stopes. INTRODUCTION An underground environment with high temperature and humidity conditions generated from various heat and moisture sources can significantly affect the thermoregulation processes of the human body. This can lead to heat-related illnesses such as heat rash, heat cramps, heat exhaustion, and heat stroke. Heat stroke is a serious illness that carries a high risk of fatality, if the underground workers are not immediately treated and the climatic conditions are not corrected (McPherson, 1993). There are two methods used to control the climatic conditions in underground mines: (1) Using ventilation and cooling systems to reduce the thermal stress on the mine workers, and (2) Reducing the heat transferred to the ventilating air from major sources such as: strata, auto-compression, mining equipment, groundwater, blasting, etc. The heat from strata and auto-compression is transferred to the ventilating air at varying degrees, based on factors such as the virgin rock temperature (VRT), the thermal properties of the surrounding rock formations, and the surface air temperature. However, the use of mining equipment and blasting processes can be managed to reduce their contribution to the mines’ overall heat load. To provide appropriate work conditions, selecting the most suitable cooling method depends on the level of heat to be removed, the location of the problem areas, and economic constraints (Brake & Bates, 2002; McPherson, 1993). Because every mine is unique, it is essential to monitor the climatic conditions to select the most appropriate method of cooling. A majority of the time, simply adjusting or re-designing the auxiliary ventilation system can efficiently remove the heat and dilute the contaminants. This may involve moving the ducting system, changing the size of the duct, changing the size of the auxiliary fan, or switching from forcing to an exhausting fan arrangement. If the required air volumes are higher than the existing primary ventilation system can supply, other measures may need to be taken to increase the airflow delivery. This may include regulating the flow in some areas of the mine to increase airflow to the desired area, adding booster fans, or replacing the primary fans."

Jan 1, 2019

By Lewis M. McNay

The Bureau of Hines and industry (mining and private) have studied the placement of hydraulic sandfill in deep-vein mines to identify existing problems and to develop techniques to strengthen the support characteristics of the sandfill. The hydraulic sandfill system, physical properties of typical classified mill tailings, and properties of sandfill modified by various techniques are discussed. Computer analysis has defined the support capability of various sandfills using actual mine field data as a reference base. High-modulus sandfill can provide adequate support in deep-vein mines to alleviate rock and pillar stresses and to reduce rock-burst incidence.

Jan 1, 1975

By Malcolm Black

Introduction The circumstances under which the gold mining industry was forced to curtail operations a few years ago are well known to all. The effect of those circumstances is particularly noticeable when one enters some of the larger mills that were designed, in better times, to treat relatively large tonnages. On their grinding floors one will observe that a number of grinding units are lying idle, and the ravages of rust are everywhere in evidence. The same applies to other equipment throughout these mills. In 1941, we found it necessary to reduce tonnage considerably in the Wright-Hargreaves mill. With the assumption that a lower tonnage would be of long duration, we began to focus our attention on some of the idle equipment with a view to re-arrangement of the flow-sheet for greater economy of operation. In an article by the writer published in the Engineering and Mining Journal (March, April, and May issues, 1939) , it was pointed out that in designing this mill there was a very limited floor space available. The choice of thickening equipment was imposed solely by the necessity for space: conservation. Thickening by gravity would have required 5,000 square feet of floor space, whereas Genter thickeners required only 1,200 square feet. As a consequence, the Genters were chosen. The decision to add flotation to the circuit was made primarily to save space. On a cost-plus-tail basis, 80 to 100 hours agitation on all pulp would produce similar overall results, but would require much more space.

Jan 1, 1948

By D. Harrington

The record of fatalities from mine explosions during the past 2 fiscal years has been anything but encouraging; more men were killed by explosions (379) than were killed from the ante cause during to' preceding 6 years combined (368). The reason for the large increase in the number of explosion fatalities during the past 2 years as compared with the previous 6 years is not entirely clear. In some instances, there has been laxity in the enforcement of State mining laws; in others, both workers and operating officials is have failed to observe recognized precautionary measures to prevent explosions. In many of the explosions that lave occurred within the asst few years in mechanized mines it has been evident that speed of operation and a demand for maximum tonnage at minimum cost resulted in neglect of ordinary safety measures.

Jan 1, 1942

By AIME AIME

THE Iron and Steel Division and the Institute of Metals Division are laying plans for a rousing meeting the week beginning Sept. 21 in the land of the bean and the cod-at Boston. The two divisions are collaborating with the American Welding Society, the American Society for Steel Treating, and the Iron and Steel Division of the A. S. M. E., to have technical sessions of widespread interest and social affairs that will compare with the best of previous years. In connection with the meetings an exhibition of production and testing equipment, heat-treating equipment, furnaces, welding equipment, and metal products will be held on Commonwealth Pier all week, where those attending may see the latest developments in the field of their own work.

Jan 1, 1931

By AIME AIME

OVER-ALL operations of the oil industry, as measured by production of crude oil and consumption of products, are almost exactly of the same magnitude as a year ago. Does this mean that the great oil industry has been undisturbed by the war? Has this industry, so vital to the prosecution of the war and to the maintenance of our way of life, been unaffected in its operations? No indeed - changes within the industry are great. It has been called upon to revamp its trans¬portation methods so as to move about one fourth of the total amount of crude and refined products by railroad tank car instead of by ocean-going tankers. Its fundamental internal economy, based on maximum gasoline yield from a barrel of crude, has been relegated to memories of the past. Rationing of oil products, which has been forced upon us in face of an abundant supply, is not only disagreeable medicine but is in itself completely disruptive to the marketing end of the-business.-

Jan 1, 1942

By J. A. Cox, R. S. Mattson

"One of the main problems encountered in employing sublevel caving is the inherent high dilution factor. The operating results at Granduc illustrate that this dilution can be closely controlled and satisfactory recoveries achieved, in base metal ores grading less than 2.0% copper equivalent, by using an assay grade control system based on the fundamental draw characteristics. The history of draw control procedures employed since the start of operations provides an effective comparison between this system and one based mainly on tonnage. The transverse and longitudinal sublevel caving mining methods are described and it is shown how improvements in design layout, operating practice and draw control in narrow complex ore zones (12-foot minimum width) have raised the operating performance of the longitudinal system to a satisfactory level."

Jan 1, 1973

By Grant R. Brown

The purpose of this opening paper is to provide an overview of incentives strategies. This overview includes a discussion of the different types of incentives, their advantages and disadvantages and their potential application to the mining setting. Objective The primary objectives of incentive plans are to increase worker (including management) effectiveness and reduce unit labor costs. These plans can be grouped into two major categories: 1) non-financial plans 2) financial plans

Jan 1, 1983

By B McCarthy

Mining has been typified of late as a boom and bust, cyclical industry operating against a steady decline in the size and quality of mineral deposits. Decreasing deposit grades and increasing costs of traditional mining techniques, all in the face of another commodity downturn, are forcing mining companies more than ever before to seek out new and innovative ways to operate. New technologies are emerging to model, control and track resources through the mining value chain, to move material about mines more efficiently, and to identify and separate ore from gangue early in the extraction process.Discovering such technologies however is only the first challenge for mining companies. Actually implementing technological change successfully has proved to be an even bigger challenge. Like for many industries, fulfilling the promised benefits for the expense and timing envisioned, has not been easy when innovative technologies are introduced.Citing the author’s insights and experiences in a number of emerging technologies, this paper explores barriers to implementing technological change in the mining context. Key elements of a change management framework, first developed for implementing mine management systems, are described to give mining executives insight into how they and their organisations can succeed through technology-driven change.CITATION:McCarthy, B, 2016. Successfully implementing technology-driven change in the mining environment, in Proceedings International Mine Management Conference, pp 89-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By J. L. Fuentes-Cantillana, J. B. Solar Menéndez, A. O. Cámara

The Principality of Asturias is a region situated in Northern Spain with two centuries of tradition in underground coal mining. In addition, its uneven relief has obliged the construction of a great number of tunnels both for railways and roads. Basing on this experience and an ever increasing need to improve on safety, the Barredo Foundation dependent on the Regional Government and the University, provides and manages a Centre for Research of Fires and Ventilation in Tunnels. The Centre has as its most important infrastructure, a tunnel 540 m long, 9,5 m wide and 8,0 m high at centre. This section coupled with ventilation equipment allows the simulation of risk conditions at real scale, which is achieved by modifying the geometry of the section and through two powerful stations situated one at either en of the tunnel. In addition, the Centre houses two test benches for fans and electrical motors at high temperatures. One bench with a re-circulation conduit is the most appropriate for tests in Transversal and Semi-transversal type of installations. The other, is for the testing of electrical motors or fans which operate in zones where the surrounding temperature is high. In this Centre, training has also been developed for Fire Fighters and Civilian Protection Personnel who have to work in fire and smoke rescue conditions in underground structures. Testing conducted at real scale enables this formation and also to improve different computer programmes in the field of Fires and Ventilation.

Jan 1, 2003