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By Carlos León

El presente trabajo señala el proceso de optimización en la recuperación del cobre y molibdeno en la concentradora de Toquepala. La implementación y desarrollo de la remolienda del flujo de concentrado desarrollan un mayor grado de liberación, y por ende, una mayor recuperación del cobre y molibdeno en el circuito. Asimismo, el descarte de relave OK-50 ha permitido normalizar las recuperaciones de cobre y molibdeno en ciertas secciones de la flotación rougher de la planta, incrementando en la recuperación del cobre de 0.8% y 1.8% en molibdeno. Por ello, es factible mejorar las condiciones de operación de la planta a través del desarrollo de pruebas metalúrgicas llevadas adelante como un esfuerzo conjunto entre todos los integrantes del equipo Concentradora Toquepala.

Sep 13, 2001

By M. van Biljon

The possible closure and subsequent flooding of South Deep Gold Mine?s neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding South Deep mine. Several technical investigations had been carried out before and during construction of the plugs in order to reduce the probability of groundwater flow through the boundary pillar between the two mines or through the rock mass immediately around the plugs. This paper describes the geological, hydrogeological and stability investigations carried out to evaluate the structural competence of the boundary pillar.

Jan 1, 2006

By Norman Disley, David B. Counter, Lionel Hebert

Misfires in underground and surface production blasts can be costly. Costs can arise from loss of resource, production interruptions, having to redrill or otherwise refire the blast (a hazardous process at best), due to added secondary blasting or breakage, and/or from increased LHD maintenance costs attributable to poor fragmentation.

Jan 1, 1996

This paper describes a mobile laboratory developed specifically for nickel prospecting, and which was designed to be operated by sub-professional staff in remote areas independently of established laboratories. An atomic absorption spectrophotometric procedure was used to determine nickel, cobalt, lead, zinc, and copper ID latentIc and sulphIde samples, with a detection limit better than 25 µg/g for all elements. The procedure was applicable to both soil and drill samples and the accuracy of the procedure, which was ±5 per cent relative at the 1,000 µg/g level was sufficient for the preliminary assessment of mineralized samples and the control of drilling operations. The analytical procedure and the means taken to ensure the necessary reproductibility and accuracy are described. One operator can carry out 400 elemental determinations per 8-hr day at an approximate cdst of 6 cents per elemental determination. The results are returned within a single day, a factor which can contribute materially to the efficiency of drilling operations.

Jan 1, 1970

By J. L. Eakin

Systematic flooding was introduced into Nowata County, Okla., in May 1931. The results of this means of stimulating the nearly depleted Bartlesville reservoir in the county has been the subject of four Bureau of Mines Reports of Investigations.2-5/ This report presents a discussion of four full-scale water-flooding projects in the Delaware-Childers field and 1 pilot project in the Curl Creek field (fig. 1). All five plants have been in operation for only a few months. Although substantial increases in the rates of oil production have been obtained 1 by the injection of water, the projects are of particular interest at this time because of the novel methods of operation and new equipment that are being employed. One project utilizes a portable "package" plant designed for a pilot operation. All of the controls for this project are centrally located. The design makes it possible to remove the test plant to another location if the project is unsuccessful or if the unit is to be replaced by a larger plant. This project also utilizes diatomaceous-earth filters successfully for the first time and makes use of plastic pipe. Another novel feature of the operation is the aeration of Arbuckle limestone water through an airlift in the supply well.

Jan 1, 1955

By Carl Hendricks, Malcolm Scoble

There currently exists no viable means of obtaining continuous feedback on blast efficiency. This paper describes the adaptation of a loading shovel to serve as a diagnostic tool to evaluate the success of ground preparation. Work undertaken in a large western Canadian open pit involved microprocessor-based instrumentation for the performance monitoring of an electric mining shovel. The monitored shovel responses proved to be reliable indicators of variations in muckpile diggability. This approach is considered to provide a very comprehensive survey of post blast conditions since such a shovel interacts which every cubic yard of a blast.

Jan 1, 1990

The phosphorus content of the banded iron formation (BIF) and of the associated iron ore deposits in the north west of Western Australia is known to vary widely, a fact which has considerable econ~mic significance. Trendall and Blockley (1970) have described the variety of textural appearances of apatite in the Hamersley Group BlF, and suggest that apatite may account for the entire phosphorus content of the unaltered BIF.A preliminary investigation using an M.A.C. electron microprobe analyser has shown that, at least in some iron ores and in partially enriched BIF and associated shales, the phosphorus occurrence is more complicated than this. A suite of samples was examined from one location which covered the entire Dales Gorge Member and some adjoining macrobands in the Mt. McRae shale, together with samples selected for their high phosphorus content, degree of ore enrichment, and position relative to the enrichment zone. Calcium apatite was not observed in any sample of ore from this sequence, despite its ubiquitous occurrence in the BIF. Silicate mineralogy in the enriched regions also differs from that in the BIF, but this change has not yet been studied in detail.The phosphorus content of goethite in one orebody is often high and appears to be in solid solution in the goethite structure. It shows little or no variability on a micro-scale within a grain, except where theremay be a zoned enrichment near boundaries and solution channels. There is also a limited solubility of phosphorus in hematite (the maximum observed by the author is 0·1 per cent P); but where the hematite is martitic (after magnetite) its phosphorus content is always low or zero. In some bands, martitic hematite has been hydrated to goethite, and this also has a very low phosphorus content. Phosphorus was not found in the silica or silicates in the ore, and even when iron enrichment is just beginning, a limited suite of samples from the BIF suggests that the phosphorus content of the chert microbands is almost entirely in the microscopic goethite nuclei (after riebeckite) scattered throughout the chert. The ability of goethite and hematite to accept phosphorus...

Jan 1, 1973

By Ray. K. Filip

The concept of installing a steel sheet pile retaining wall into the ground by "pressing" has resulted in the development of various equipment solutions over the last thirty years e.g. Taylor Woodrow ?Pile Master', Giken 'Silent Piler" & Tosa 'Still Worker?. Dawson Construction Plant Ltd (DCP), have recently advanced the pile pressing concept with the introduction of their 'Push-Pull' system. This advancement offers significant improvements in the quality of installation compared with traditional pressing solutions but also greater versatility, higher productivity and, most importantly, generates new opportunities through a wider range of applications for "silent piling'. This paper will focus primarily on the use of the Push-Pull concept in the construction of a unique "integral" bridge in Milton Keynes, England. Finally, the paper touches on the development of quiet, vibration-less pile extraction equipment, which allows steel to be considered the foundation material of choice for truly sustainable construction. It is no longer acceptable to leave unwanted piles in the ground.

Jan 1, 2006

THE art of mine surveying has made very great progress in recent years, and is still advancing, perhaps faster than any other branch of surveying. The scope of the mine surveyor's duties has greatly increased, his instruments and methods have improved, the responsibility of his position is greater, and the end is not yet in sight.It might be supposed that such a steadily growing subject would have an adequate literature, but this is by no means the case and outsiders commonly judge mine surveyors by their text-books. Hardly any condemnation can be too strong for most of these books. The English books truckle to the antiquated and crude methods apparently still in use in England, and thereby largely aid in perpetuating them; they commonly in illustrative examples give the distances in fathoms, feet, and inches; they spend page after page discoursing on instruments that should have been forgotten long ago; they try to antagonize theory and practice by detailing such calculations as that a certain vein will contain 2,003.907 pounds of galena per square fathom, and then reduce this amazing quantity to hundredweights, quarters, and pounds. Nothing can be more unscientific, or, for that matter, less businesslike, than unwarranted assumptions of accuracy; it is, perhaps, the greatest curse of applied science. Here we have a calculation to thethousandth part of a pound, when there is probably an unavoidable error of two hundred pounds. What shall we say of a man who explains how to measure the depths of shafts to the hundredth part of an inch by means of short brass rods screwed together...

Jan 1, 1909

The presence of undetonated explosives in a rock face after firing constitutes a hazard which can result in a fatal or serious accident if undetected before drilling commences.Most accidents caused by drilling into explosives are the result of failure to examine the working face properly and lack of care in subsequent drilling operations; it is not always realized that explosive may be left in the butts of holes or may be driven into cracks or crevices in the rock.Obviously the best means of preventing accidents of this nature is to adopt methods of drilling, charging and firing which will reduce the hazard to a minimum.There are three ways in which undetonated explosives may be left in the rock face, namely:1. Misfires.2. Cut-off shots.3. Incomplete detonation or failure of the charge to propagate throughout.MisfiresNo attempt will be made in this paper to deal fully with the question of the prevention of misfires, as apart from the fact that most of the preventive methods are well known, it is believed that if the miner receives his explosives and means of initiation in good order, and proper care is taken in their use, the failure of a charge to fire will be a rare occurrence. The provision of central fuse capping stations on mines has gone a long way towards the elimination of misfires caused by the mishandling of safety fuse anddetonators.

Jan 1, 1956

By J. Roth

The purpose of the present study is to increase the safety of explosive storage. This was accomplished by: a) review of the histories of recent and past magazine explosions to define causes and trends; b) observation of present-day explosive storage conditions and practices at active mines; c) examination of existing Federal regulations on explosive storage to determine whether they address all conceivable safety problems, whether they contain redundant or obsolete standards, and whether their intent is clearly stated; d) recommendation, for safety improvements and for revision and clarification (if necessity) of governmental regulations. Magazine explosions are rare. A recent increase in magazine explosion frequency must be attributed to a large increase in deliberate (criminal or malicious mischief) explosions. Fires of various origins account for the remaining explosions of the past decade. During 1884-1926 several lightning-generated explosions occurred in non-metal magazines, but none recently. It appears that the contents of a well-constructed, metal magazine are immune to direct lightning strikes, regardless of whether the magazine is grounded or not grounded. Grounding a metal magazine cannot be harmful, but it may well be superfluous. Magazines were observed at 34 widely separated mines and storage problems were discussed with personnel at these mines. In general, storage conditions and practices were found to be satisfactory. Usually, only small quantities of explosives are stored on mine property since most explosives are brought in by suppliers when needed. MSHA and BATF standards on explosive storage appear to cover safety aspects adequately. However, certain revisions are recommended to clarify some of these standards and to reduce inconsistencies in their enforcement.

Jan 1, 1983

By R. S. Dean

In an earlier paper Dean and Hersberger5/ gave preliminary results a d discussed briefly the use in flotation of organic reagents of the type known in the textile industry as "wetting agents.? These reagents are those with a molecular structure comprising a long hydrocarbon chain attached to a. highly molar or hydrorhile group in such manner that ionization is nearly complete in dilute solution and the resultant ionic grouping has a very considerable hydrophile-lipophile unbalance in the structure. As a result of this characteristic structure these reagents are more or less powerful frothers and emulsifiers. Ten the degree of hydrophile-lipaphile unbalance is sufficiently great and specific chemical factors are absent these compounds behave in flotation as noncollecting frothers insensitive to reason¬able changes of pH.

Jan 1, 1937

By Dale Bartholomae, David Harrison, Edward J. Walter

Methods that involve the use of signature blast holes in order to identify the particular frequency characteristics of a geographical area are widely available. Information acquired can be used to determine optimum blast hole timings to produce the desired constructive and destructive inference. However, these types of analyses can be both complicated and expensive. This study will investigate the use and practicality of signature hole and/or shift and sum analysis software and their application to small diameter construction utility blasting operations in Pennsylvania and faster moving projects in general. A determination will then be made as to whether this technology can be utilized by today’s blaster, from both a functional and a cost effective basis. Single hole blasts will be detonated on various smaller construction projects and will be monitored with an array of seismographs. The collected data will be analyzed in order to determine the optimum timing between holes to produce the preferred frequency content while keeping in mind the explosives user’s current inventory of blasting supplies.

Jan 1, 2005

By D. H. Gurinsky, D. G. Schweitzer

The empirical equilibrium constantsd the heat of reaction for the reduction have been determined from 300° to 500°C. The mechanisms of the oxidation of uranium and magnesium from dilute bismuth solutions have been investigated. The kinetics of some of the reactions were affected by air adsorbed on the uranium oxides. THE Liquid Metal Fuel Reactor studied at Brook-haven National Laboratory uses a solution of uranium in bismuth as the fuel. Corrosion and stability problems require that the fuel solution contain corrosion inhibitors and deoxidants. Of the additives tested, magnesium has been found to be the best deoxidant and zirconium the best corrosion inhibitor in bismuth. Some experiments1 indicate that magnesium may play a secondary role in increasing the effectiveness of zirconium in inhibiting corrosion. The work reported here was intended to determine the relative concentrations of Mg and U required to prevent oxidation of the uranium fuel in the event of an air leak. In addition, an attempt was made to identify some of the mechanisms of the oxidation and reduction reactions occurring in the liquid bismuth solutions. EXPERIMENTAL Apparatus and Procedure—The equipment shown in Fig. 1 was designed so that the reaction kinetics could be studied as functions of temperature, melt composition, pressure, and flow rate. At the start of a run, the 10-liter bell jar (F) is removed by opening the bottom Dresser fitting (L), and the bismuth and additives are placed in a pyrex crystallizing dish (I). The bell jar is replaced, the system is evacuated to 10-5 to 10-6 mm Hg and then the heater (J) is turned on. When the selected temperature is reached, the oxidizing gas is admitted to the system to the desired pressure as read on the manometer (D). Gas is introduced through the slide tube (Q) which has a pyrex frit (R) sealed to its bottom. Stirring is accomplished by immersing the end of the tube in the melt. To maintain a constant pressure under flow the input and evacuation rates must be equalized. To obtain this condition stopcock (C) is closed and flowmeters (B) are matched. The reaction is "stopped" by closing the inlet flowmeter and quickly evacuating the system. To obtain a liquid metal sample, the system is evacuated with the sampler positioned near the surface of the liquid. The sampler, Fig. 2, is then immersed until its thermocouple reading matches thermocouple (G) Fig. 1. The system is then pressurized with helium which forces the solution through the frit. Twenty to 30 min elapsed between the time the system was evacuated and sampled. During evacuation and pressurization of the system, the temperature variations did not exceed ± 5°C. While bubbling occurred the temperature remained constant to within 1/2 oC. The volume of the equipment was determined by adding a known volume of air at atmospheric pressure to the evacuated system and noting the resulting pressure.

Jan 1, 1962

Introduction MINING IS THE BRANCH OF INDUSTRY involving the exploration and removal of minerals from the earth (figure 1). Mining is one of the oldest and most important endeavors of humankind, because it provides the raw ingredients for most of the material world around us and, like agriculture, is the lifeblood of civilization. The main objective of any type of mining is to remove the valuable material economically and safely with minimum damage to the surrounding environment. The Earth has many natural resources on which we depend that must be mined. Coal, oil, gas, and other mineral fuels are used for heating electricity, and numerous industrial processes. Nonfuel minerals such as iron ore, precious metals, and industrial metals, and nonmetallic materials like sodium and potassium are used in chemical and agricultural applications. Even crushed stone used in road building and other construction projects must be mined. Mining affects our standard of living and impacts almost everything we do. A myriad of items that we use in our homes and offices and for transportation, communications, and national defense all require minerals (figure 2). For example, more than 30 different minerals are needed to make a television or telephone! Table 1 lists several commonly mined materials and some of the end uses in our daily lives.

Jan 1, 1995

By O. N. Sikazwe

The Nchanga Cu-Co ore deposit of the Zambian Copperbelt, is hosted in Neoproterozoic siliciclastic-carbonate sedimentary rocks, and it consists of two orebodies: the Lower Orebody (shale) and the Upper Orebody (arkose). Refractory Cu ores present in the Upper Orebody comprise 150 Mt with average 0.87% Cu, and are characterized by inadequate recovery of copper by leaching. This materials characterization study, conducted on refractory ore samples from the Upper Orebody using optical microscopy, QEMSCAN®, and microprobe, has shown that copper occurs mainly in biotite, phlogopite, malachite, pseudomalachite and goethite. QEMSCAN® has quantified the abundance of each phase and total Cu deportment in each phase.

Jan 1, 2008

By H. Sevim

The utilization of high sulfur Illinois coal by utility plants has been decreasing since the enactment of 1990 Clean Coal Air Act Amendment. Illinois coal producers can make their coal saleable by offering the choice of taking the combustion by-products from the utility plants and placing them in the abandoned sections of their mines. To be competitive, however, coal producers need to select an environmentally acceptable transportation-handling-placement system through which the cost-per-ton of by-product disposed can be minimized. In this paper, a few such systems are presented. The favorable operating range of each system is determined in terms of distance and tonnage. A case study is given whereby cost analysis is conducted for an underground coal mine receiving by-products from two Illinois utility plants.

Feb 24, 1997

By E de Villiers

Several methods exist by which the capacity of a dense media separation (DMS) plant can be improved: 1) Increase the feed rate in spite of efficiency 2) Replace with bigger equipment 3) Add whole new module 4) Replace total plant 5) Change over to four shift/ seven days per week roster 6) Replace with alternative process 7) Increase the availability and utilization Options 1 ? 6 have varying degrees of cost implications. The seventh option would seem to be the easiest. Normally it is also the function of the plant operating and maintenance team to maximize this. Usually higher operating and maintenance cost are associated with an increase in these parameters. A general principle that is applicable to plants and systems is that as the complexity increases, the total availability decreases. By simplifying the flow line it may be possible to reduce cost while at the same time increase the availability and utilization. The typical standard DMS flow line contains components that compensate for the variance in pump performance or for the inefficient recovery of ferrosilicon with additional equipment. Things have changed though: 1) Advanced electronic control and monitoring is possible 2) More efficient magnetic separators are available 3) New more user friendly densifiers are available ORIGINAL FLOW LINE In principle the process consists of four flow lines or streams 1) Ore flow ? the feed is divided into a waste and product stream by means of the separating vessel

Jan 1, 2006

Ensuring the success of a major resource development project, whether in the Gippsland Basin or elsewhere, is typically both a complex and costly process. It is therefore imperative from the point of view of the proponents of such a project - and in particular the financiers - that everything possible be done to minimise administrative confusion and delay in the establishment phase of the project, and to put systems in place which enable the project to run smoothly and efficiently in the later stages of its development and operation. An essential element in this process is ensuring that the project management is able to come to terms with and deal effectively with the relevant planning and environmental laws.

Jan 1, 1992

Commodities statistics and other information are available through the following three systems: Internet Access: To acccess the USBM Gopher server on Internet, connect to: gopher.usbm.gov port 70, using gopher client software. Or contact the Systems Administrator for technical questions: Matt Klevemann, 412-892-6499 (klevemmc@miner.usbm.gov) These USBM materials are available on Internet, with more to come in the future: Publications and other research findings, including this bimonthly publications list, newsletters, tech transfer updates, enviromental technology research, health and safety information. USBM software products Media materials and speeches. Mines Data: Computer bulletin board. Log on via modem through 202/501-0373, or call 202/501-0406 for technical assistance. Mines FaxBack: Return fax service. 1. Use the touch-tone handset attached to your fax machine's telephone jack. (ISDN [digital] telephones cannot be used with fax machines.) 2. Dial 202/219-3644. 3. Listen to the menu options and punch in the number of your selection, using the touch-tone telephone. 4. After completing your selection, press the start button on your fax machine.

Jan 1, 1995