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By N. Charue

An international prediction event was carried out within the framework of a 30-pile testing program organized in a sandy soil in Belgium (Limelette). That program called upon sev­eral testing methods: static load tests, Statnamic testing, and dynamic testing. This paper provides a summary of received predictions and results obtained from the static pile load tests, which were carried up to failure of the instrumented piles. The comparison between predictions is made using load-settlement curves with reference to the results of the static load tests. The predictions are based on a geotechnical approach using an extensive soil investigation program and a dynamic approach using the dynamic load test data.

Jan 1, 2002

By James T. Kemp

SOME interesting and, to American eyes, rather unusual processes for refining impure aluminum derived from scraps were found by American and British investigators who went into Germany in 1945 for the Technical Industrial Intelligence Committee Of the Joint Chiefs of Staff. What was found was recorded in a series of reports (see page 14), many of which have been released for general reading. This paper gathers under one title and summarizes the German work in refining light metal scrap. Reference must be made to the original reports for greater detail. Basically, the occasion and stimulus for the German developments in treating light metal scrap were hard necessity. Germany needed the metal for a rapacious war industry. Adequate supplies of new aluminum from reduction works were not assured. Great quantities of airplane and other light metal war scraps were forecast. It was evident that the scrap metal would have to be reabsorbed by the producing industry and would have to be kept of good quality. The normal current production of manufacturing scrap was being and could be consumed as generated. It offered no technical problem. The mixed scraps, especially those arising from crashed and decommissioned airplanes, however, presented problems of another kind. AIRPLANE SCRAP The recovery of usable aluminum alloy from the mixed assemblies that made up the piles of airplane scrap was attacked in different ways by different groups and with differing degrees of success. Three procedures actually were used On a commercial scale, one was in pilot-plant stage and another had come to a halt in the laboratory a year before Germany collapsed. Four of these five processes actually involved "refining"; that is, some measure of purification of the metal after melting. SORTING AND SEPARATION ON A SLOPING HEARTH The simplest procedure for utilizing airplane scrap involved no refining in the strict sense of the word. This was the practice adopted by two representative plants visited by the author, the Leipziger Leichtmetalle Werke, Rackwitz, Saxony, and the Vereinigte Leichtmetalle Werke, Hanover. These firms did essentially the same thing that was done in England but not with equal success, to judge by their shorter experience, the smaller tonnage handled and by the number and quality of alloys produced. The two German firms named rough-sorted scraps by their easily recognizable alloys, essentially by part and shape. They used hand labor to chop and hack and tear apart. The easily separated heavy metal and nonmetallic scraps were discarded as they were found. Steel and the higher-melting-point metal parts riveted to aluminum or built into

Jan 1, 1947

One of the seminal pioneering papers in reserve evaluation was published by Danie Krige in 1951. In that paper he introduced the concept of regression techniques in providing better estimates for stope grades and correcting for what later became known as the ‘conditional bias’. In South Africa, the development of this approach led to the phenomenon being dubbed the ‘regression effect’, and regression techniques ultimately formed the basis of simple kriging in Krige’s later papers. In the late 1950s and early 1960s, Georges Matheron (1965) formulated the general theory of ‘regionalized variables’ and included copious discussion on what he termed the ‘volume-variance’ effect. Matheron defined mathematically the reason for, and quantification of, the difference in variability between estimated values and the actual unknown values. In 1983, this author published a paper that combined these two philosophies so that the ‘regression effect’ could be quantified before actual mining block values were available. In 1996 and in some earlier presentations, Krige revisited the regression effect in terms of the conditional bias and suggested two measures that might enable a practitioner of geostatistics to assess the ‘efficiency’ of the kriging estimator in any particular case. In this article, we revisit the trail from ‘regression effect’ to ‘kriging efficiency’ in conceptual terms and endeavour to explain exactly what is measured by these parameters and how to use (or abuse) them in practical cases.

Jan 1, 2015

By Evan Boone, Peter Bellairs

A technical services visit was conducted to determine the initial parameters to successfully presplit several benches for an input crusher installation at the Wolffdene quarry. The paper details the preliminary design utilising both detonating cord only and specialised presplit product charges and compares these to the final designs utilised based on site experience. The role of accurate drilling, explosive loading and geology in obtaining successful cost effective presplits is highlighted.

Jan 1, 1998

Silver is one of the three major metals produced from the Broken Hill mines. The accurate determination of the silver in these ores, therefore, is of economic importance.With due appreciation of the divergence of opinion of many who are interested in the subject of the determination of silver, the writer has been prompted to present the results of some recent experiments on silver losses during cupellation and conclusions from these experiments in the present paper. The losses of silver in the fire assay for this metal are due to silver retained in the slag during the fusion or scorification of the ore, and to silver volatilized from, and absorbed by the cupel during the process of cupellation.The literature describing the results of experimental work on silver losses due to the above causes is extensive, and the general conclusion of these experiments is that the silver lost in the slag is small, but that lost by cupellation is larger and more variable.The term cupellation loss in this paper refers to the total cupellation loss, no distinction being made between the absorption and volatilization losses.Volatilization loss is shown by King to be 0.5% of the total cupellation loss and, as it is generally accepted among assayers as being only a small fraction of the cupellation loss (3) (5), it will not receive further consideration in this paper.The factors causing the loss of silver by cupellation and the precautions to be obs~rved to reduce the loss in this operation are described in (1), (2), (3), (4) and (5). The...

Jan 1, 1940

By G Alan Foster

The presence of approximately 600,000 attorneys in the U.S.A. and the determination by the courts that blasting is considered an 'ultra hazardous' activity makes every practical blaster aware that at some time during his working life he will probably be faced with defending himself in court.

Jan 1, 1982

By C. P. Davenport, Garth Duell

What are the projected electrical power needs of the nation and of the Northwest during the next 15-20 years? No one who has researched the subject has reached a substantially different result than the following simple conclusion: electrical power requirements are doubling every decade. There are some who question the necessity of a power company's need to install capacity every ten years equal to what it has done during its entire previous history; there are even those who would argue that such growth should be arbitrarily curtailed. However, a power company must, by law, meet its responsibilities of providing the energy the public expects when the switch is thrown.

Jan 10, 1972

The excavation of ramps and tunnels often requires high-speed development with (or without) the use of high-energy mining equipment such as loaders, dump trucks, TBMs and roadheaders. This high-speed development creates a challenge in terms of providing a safe and productive working environment. For example, heat from continuously exposed surrounding rock, heat from broken rock, heat generated by mining equipment, potential in flows of hot ground water, pollution from associated diesel equipment and the distance of the advancing face from fresh through-ventilation all have to be taken into account when designing ventilation systems for high-speed ramp and tunnel developments. This paper discusses methods of achieving acceptable environments at the face and along the length of the tunnel. The methodology has been successfully implemented in the development of long (up to 20 km) TBM drives in the Lesotho Highlands Project and in mining projects in hot rock using drill and blast methods as well as mechanized methods using continuous miners and roadheaders. The determination of heat loads includes calculation of the heat flow within the surrounding rock, evaluation of the operating cycle of the equipment and the contribution to the overall heat load of the broken rock as it travels out of the tunnel. The determination of heat loads from surrounding rock in new tunnels required a modification of the algorithms generally used for established excavations. The paper also examines the use of, for example, mobile duct and fan systems to ensure that fresh air is delivered to the specific areas where workers are located.

Jan 1, 2000

By Aram Grigoryan

This paper addresses historical aspects and construction sequencing of the subway complex under Columbus Circle in Manhattan; the structural elements of the rehabilitation and new construction; and the challenges associated with design and construction. PB is providing engineering services to New York City Transit (NYCT) for the rehabilitation of the 59th Street/Columbus Circle Station Complex that services over 150,000 customers daily. The project involves structural repairs, modifications and new construction requiring underpinning and temporary supports, custom framing details, and construction staging procedures to meet stringent limitations within the operating transit station and around the Columbus Circle street intersections.

Jan 1, 2008

Bacterial leaching represents an unusual problem in biochemical engineering, because the substrate for bacterial growth is not supplied directly, but is a product of another reaction, the leaching of mineral particles. Leaching arises from the bacterial oxidation of ferrous ions to ferric ions, which in turn oxidize the mineral. For the bacterial dissolution of pyrite, these reactions are: [ ] (Y represents a stoichiometric yield factor, and N represents the amount of bacteria.) Equations [1] and [2] represent a cyclic auto-catalytic system since more ferric ions are added to the system with an increase in the extent of leaching.

Jan 1, 2000

By R. F. Stevens

A laboratory method for examining crude shale oil is described. The method uses only about 500 ml. of sample and a limited number of analytical determinations. Results provide information on the general characteristics and composition of an oil and serve as a basis for comparing different oils. However, the method does not provide for direct estimates of yields of commercial products. Analyses of 10 oils produced in the United States by different methods of retorting and of 10 shale oils from commercial-scale operations in 6 foreign countries are given. The shale-oil-analysis method presented in this paper is based on and employs the same equipment as the Bureau of Mines routine method for analyzing crude petroleum. As shale oil contains groups of compounds not generally found in petroleum, several modifications of the petroleum method that might increase its suitability for application to shale oil were investigated. The modifications included in the present method take into account the apparent poor heat stability of shale oil and the presence of large quantities of olefins and nitrogen compounds.

Jan 1, 1952

By W. X. Wang

In the mining and quarry industries, rock fragments are often transported by conveyor belt. To estimate the qualities of the rock fragments (i.e., size distribution and shape), an operator must take samples from the conveyor and manually perform a sieve analysis, which is time-consuming and tedious. Alternatively, an image-analysis system can be used to monitor the fragment quality on a fast moving conveyor belt. However, images of fragments on a fast moving belt vary to such a degree that the quality of any two successive images are not the same, and some of the images are of such poor quality that they are unrecognizable by human eyes. If poor-quality images are directly analyzed by a segmentation algorithm, the analysis will not be satisfactory. To resolve this problem, it is necessary to use an image-classification pro-gram for the automatic selection of fragment images with good quality. Because of this need, an image-classification program was developed and tested both in the laboratory and in the field. Testing of the system on different types of fragments showed that the system works reasonably well.

Jan 1, 1996

By Waraporn Piyawit

Grinding sludge from the sintered neodymium-iron-boron (NdFeB) magnets production process was enriched with critical rare earth elements (neodymium, dysprosium and praseodymium), which can be up to 30% in the magnets. The demand of NdFeB magnets are simultaneously growing. Therefore, rare earths recovered from waste residue would reduce the demand of rare earth elements from primary sources. In this study, the feasibility of recycling rare earths through a hydrometallurgical process was investigated. The selective leaching of Nd from grinding sludge can successfully raise the rare earths concentration to 70%. The necessity of an oxidation pretreatment to improve the selectivity between Nd and Fe will be described.

By J. M. Mutmansky, L. Xu

"This paper outlines the results obtained when sampling twenty underground coal mine sections, each in a different mine. The sampling effort was oriented toward a detailed characterization of coal mine dusts and thus eight-stage Anderson Model 298 impactors were used as the primary collection instrument. This instrument allowed a rather detailed size distribution for each of the particulates sampled. Because four of the mines used diesel outby equipment and/or diesel shuttle cars at the face, it is possible to make some comparisons on the particulate distributions in diesel versus non-diesel mines.One of the more interesting results is the pattern that exists in mines that contain only diesels used for outby utility haulage. Particulate in these mines seem to be consistently heavy in the fine size ranges, perhaps being of significant concern to the industry. While no definite conclusions can be achieved from the limited data collected in this study, the data indicates that more detaile~ study of particulates in diesel mines is needed so that some idea of the particulate loadings in diesel mines can be achieved."

Jan 1, 1988

By John G. Henning

The Hoyle Pond underground mine is located in the Porcupine Gold Camp, 18 km east of downtown Timmins. Since the initiation of production in 1985, the operation has produced in excess of 1.9 million ounces of gold at a grade of 15 grams per tonne. Currently, Hoyle Pond ranks 8th in total ounce production for all past and present producing mines in the camp, with the highest head grade of any of the significant past, or present producing mines in Timmins. Cut and fill, shrinkage, longhole and panel mining methods are employed to excavate the narrow gold bearing structures. Using illustrative examples, this paper provides an overview of factors, such as geologic setting, rock mechanics challenges and mine infrastructure, which influence mine design at Hoyle Pond.

Oct 1, 2004

By P Rowe

New Zealand Steel's Taharoa titano-magnetite mine, south of Auckland, set two national load records when it transported around 2000 t of mining equipment three kilometres overland on time, under budget and without safety incident. It was the first time in New Zealand that four platform trailers were assembled end-to-end to transport a load. It was also the first time that a single load of 1000 t was transported on platform trailers. The need for the relocation of all equipment was realized five years ago. It took two years of planning and specialist advice to relocate the mine's 250 t dredge, 500 t surge bin, 1000 t concentrator plant and ancillary equipment from the Southern Mining Region across a specially designed haul road to the Central Mining Region. The project was carried out during a six-week shutdown in early 2001. Two dry docks were constructed, one at each end of the relocation route. The equipment was floated into a dismantling pond that was interconnected with the dry dock in the Southern Region. Through pumping, the water levels were controlled to allow transfer of the separated units from the dismantling pond into the dry dock. Once drained, sets of self-elevating platform trailers were used to transport the main units, one at a time, between the dry docks. Five prime movers were used to pull the loads. At the receiving end, the units were off-loaded in a dry dock interlinked with ,the first mining pond. The equipment was relocated because the reserves in the Southern Mining Region were mined out. A natural watercourse û the Wainui Stream û defines the northern boundary of the Southern Region and the objective became to relocate the mining plant to the other side of the stream and re-establish in the Central Region. The project team selected the trailers as the most effective means of transporting the equipment, particularly given the non-invasive means of crossing the Wainui Stream. Negotiations with prime contractor Tranzcarr Heavy Haulage Ltd commenced in mid-2000. The remainder of 2000 was spent in developing concepts with the contractor, detailed designing, preparing the dry docks, haul road and initial mine plan for the Central Region. These activities occurred with no conflict to the normal site production.

Jan 1, 2001

By William R. Bond, Jim V. Rouse

Introduction The pressure/vacuum (p/v) lysimeter or soil water sampler has become useful for monitoring vadose zone or unsaturated zone water conditions. The soil water sampler was first introduced around 1961. It was used as a monitoring and research device for studies in agriculture and soil contamination around landfills. Since then, it has been used for many purposes. The use of p/v lysimeters at mining facilities to monitor for solution loss is a relatively new idea. The primary purpose of the lysimeter here is to function as an early warning system. It detects leakage through liners of tailings ponds, heap leach pads, and leachate holding ponds. Their use has proven valuable for collecting baseline data and detecting loss of precious leachate fluid. Different lysimeter designs are capable of vadose moisture sampling from near the surface and down to 90 m (300 ft). They are also capable of sampling soil moisture or saturation plume contaminants from areas not accessible by conventional water well installations. The most common installations are usually simple and cost-effective. In many cases, they can be installed without the use of heavy drilling equipment. A properly placed and installed lysimeter can detect solution leaks in several days or weeks. A conventional perimeter monitor well may take months or years to detect a leak of the same magnitude. A discussion on the general design and installation of p/v lysimeters will give an understanding of its versatility. Three case studies of lysimeter installations at mining sites will be examined in detail. Design, Installation, and Sampling Design The basic design of a p/v lysimeter chamber consists of a porous material through which the soil is drawn into a collection chamber. Access tubes run from the unit to the sample station at the ground surface. Most units currently available range from 25 to 76 mm-diam (1 to 3 in.-diam). The sample collection chamber, or body, can vary from 0.6 to 1.8 m (2 to 6 ft) in length. The body can be constructed of PVC casing or Teflon, depending on the installation desired. The collection chamber functions as a holding reservoir for the collected soil moisture. The intake, or porous material, on the lysimeter is the most complex and vulnerable portion of the unit. The pore size selection varies based on the needs of the installation, type of fluid to be sampled, and type of soil material surrounding the unit. Teflon (PTFE) and porous ceramic are used in fabrication of the porous inlet portion. When using a Teflon material, which is hydrophobic, a larger pore size of 70 µm is needed to overcome surface tension and draw water into the collection chamber. It is typically used at sites involving organic contamination, because of its inert properties. Ceramic material is generally hydrophilic, having less surface tension. Therefore, it has a smaller porosity range to conduct the moisture through the porous medium while under vacuum. Pore sizes may be selected from 0.16 to 6 µm, and can be manufactured for the specific needs of the installation. The final major design component of the p/v lysimeter is the access or sampling tubes. The tubes are usually of 6.3-mm-outside-diam. (0.25-in.-outside-diam). They are made of rigid polyethylene or flexible Tygon with a wall thickness of 1.5 mm (0.06 in.). The con-

Jan 4, 1985

By L. Nahai

Overall mineral industry productive activity in Europe increased in 1965, following general upward trends in gross national product and total industrial production4 recorded. The gross national product of non-Communist Europe in market prices in 1965 was estimated at $572 billion and that of Communist Europe at $409 billion. However, the extractive sectors of the mineral industries generally did not fare as well as the processing sectors. In fact, a number of countries recorded lower production levels in this sector in 1965 than in 1964 and most countries had a lower growth rate in extractive industry output than in overall industrial output. Among the non-Communist nations of Europe, a general decline in coal production and lower levels of iron ore output in France, West Germany, and Luxembourg contributed significantly to the smaller growth rates or declines in extractive indexes. Where higher indexes were registered, this generally resulted from the performance of the petroleum and natural gas industry; exceptions were Greece, Norway, and Sweden. The decline recorded for Czechoslovakia was attributable entirely to poorer performance by that nation's coal industry.

Jan 1, 1967

By M. J. Beus, B. Stewart, S. Iverson

Synopsis U.S. Mine Safety and Health Administration (MSHA) accidents statistics have identified ore-pass hazards as a significant safety problem in U.S. underground metal mines. The statistics show that nearly 75% of injuries are directly or indirectly related to pulling or freeing of ore-pass chutes, the use of hand tools in ore passes, fails of broken rock in ore passes and structural failures of chutes or gates and ore-pass walls. Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) are investigating hazards in and around ore passes in hard rock mines. Risk assessment methods, such as fault-tree analysis, have been employed to identify the most probable causes of orepass failures, define research priorities and analyse the factors that result in malfunctioning and unsafe ore passes. Static and dynamic loads are being measured in a laboratory setting with the use of a reduced-scale orepass mock-up. Field tests are being initiated in mine ore passes to determine static and dynamic loads. Data from the test ore passes are being compared with data from the mine to characterize true system behaviour. Computer modelling with the use of closed-form solutions, finite-element analyses and a newly developed particle flow code predicts static and dynamic leads from the flow and the impact of ore and waste in the ore pass. Preliminary results indicate that dynamic impacts from ore and waste rock might be considerably greater than expected. The total static load is substantially less than is typically used fur the structural design of chute and gate support members. It is suggested that damping factors, normal and shear stiffness and mass frictional characteristics have a significant effect on particle flow and resulting impact loads. This is being verified with the use of results from laboratory tests, field tests and particle flow analyses. Ore passes are vertical or steeply inclined openings in a rock mass through which ore and waste are transported and where they mar also be stored. A typical underground mining system is shown in Fig. 1. The arrows indicate the locations of ore passes and loading pockets and their relative configurations. The control of material flow is potentially one of the most hazardous operations in underground mining. According to MSHA data. most of the ore pass-related accidents in the U.S.A. are associated with the loading-unloading cycle and removal of blockages from ore passes. In particular, attempts to free ore hang-ups have resulted in multiple fatalities. The hazards are obvious; there is uncertainty as to when the ore will break loose and miners are unable to escape falling rock to a safe location. Although ore passes and chutes and gate systems for underground metal and non-metal mines roust meet the requirements specified in the U.S. Code of Federal Regulations (CFR). Parts 57 and 75, recent structural failures of ore-pass linings and gates have underlined the lack of adequate ore-pass design standards available to both MSHA enforcement staff and mine engineers. Because of the importance of an ore pass to the safe operation of a mine design criteria need to be assessed and new guidelines developed. Researchers at the Spokane Research Laboratory of the Nationals Institute for Occupational Safety and Health (NIOSH) are investigating hazards in and around ore passes in hard rock mines and studying design criteria for ore passes. The near-term goal is to conduct laboratory and field experiments and computer modelling to evaluate the ore-pass design criteria currently used. Literature searches, field site

By K. L. Bainbridge

This report describes the results of a study to determine which types of, and to what extent, mining wastes can contaminate groundwater through leaching of acid-forming or potentially toxic constituents. The primary focus of this study was on coal mining wastes, especially overburden spoils and preparation plant refuse. In addition, the potential for contamination by leachates from clean coal stockpiles was also examined. The study approach included investigation of (a) the amounts and geographic locations of mining wastes in the United States; (b) the chemical character of mining wastes, especially with regard to potentially acid-firming or toxic constituents; and (c) the extent to which acid and/or toxic components are leached from mining wastes by rainwater. To evaluate the leachability of coal wastes, a laboratory waste leaching method was developed during this study to specifically simulate the leaching process over a long-term. Waste samples collected during this study were also leached by the EPA extraction procedure and ASTM waste leaching method. Results of the three leach test methods were compared to evaluate their relative capabilities to predict the leachability of mining wastes.

Jan 1, 1980