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By H. Polat, Q. Hu, S. Chander

The collection efficiency of dust particles was determined in a laboratory dust chamber equipped with a water spray. Measurements were made in the presence of selected nonionic, cationic and anionic surfactants. For the nonionic and the anionic reagents, efficiency was maximum in a narrow range of concentration. The surfactant concentration corresponding to high collection efficiency was usually much below the commonly used concentration of l%, however. In comparison, much higher collection efficiency was observed for a cationic surfactant at extremely low concentrations. For delineating the mechanism of capture of dust particles, surface tension and contact angle results were used to obtain a correlation between the work of adhesion and the efficiency of collection. Such a correlation was reasonable for the nonionic surfactants but not for charged surfactants. In the latter case, electrostatic interactions between charged droplets and particles were more important, especially for the cationic reagent.

Jan 1, 1992

By A. Lane

The socio economic risks of mining in South Africa have been emerging for some time now, and have been brought into sharp relief by recent events in the platinum sector. The slow pace of social upliftment in the country has lead to widespread social unrest with consequent calls for different forms of resource nationalism. Fundamentally, the key stakeholders are not fully aligned, and are not engaging productively. This poses significant above-the-ground risk to mining companies. Measuring social impact, deploying inclusive solutions and engaging effectively with stakeholders are three ways in which mining companies can mitigate this risk.

Jan 1, 2013

By Dennis J. Riley

A. This outline addresses what a sub-contractor, or a subsub-contractor should do to get paid in the event the general contractor or building owner files for bankruptcy. B. Negotiating payment terms. Progress payments vs. "pay when paid". How a sub or subsub can avoid financing the contract. C. Court interpretation of "pay when paid" clauses allow postponement not excusal of payment. See, e.g., Seal Tite Corporation v. Ehret. Inc., 589 F. Supp. 701 (D.N.J. 1984) (where the court held that the general contractor could not delay payment indefinitely to the subcontractor in the event of non-payment from the owner); United Plate Glass Co. v. Metal Industries. Inc., 525 A.2d 468 (Commw. Ct. Pa. 1987) (where the court held that payment from owner was not a condition precedent to paying subcontractor but instead a timing mechanism indicating when payment should be made); But see. Straham v. Landis Construction Co., 499 So. 2d 417 (La. App. 4 Cir. 1986) (where the court strictly interpreted the "pay when paid" clause).

Jan 1, 1991

By D. Schreuder

Conditions in the South African market relating to atmospheric emission control has changed dramatically over the last 10 years. Companies have become more responsible, environmentally aware, and have to comply to more stringent environmental limits set by legislation. This paper describes briefly the current best available atmospheric pollution abatement technologies relating to particulates, acid gases, NOx, acid mists, aerosols, mercury, dioxins and furans. Mention is also made as to the best practices for product work-up and waste product disposal.

Jan 1, 2006

Traditional fine grinding mills in mineral processing relied on the use of steel medium for particle size reduction. The successful development of the Isa Mill(a horizontal stirred mill with 3000 litres of net chamber volume and 1120 kW rated motor power)adopted a novel product separator design that has led to a major revision of medium use in fine grinding. The Isa Mill separator has also successfully operated with a wide variety of medium types such as silica sands, river gravel, smelter slag, run-of-mine ore fractions and steel shots, with size ranges from 0.5 to 10 mm. A great flexibility of the Isa Mill operations has been achieved for processing a feed as coarse as 120 um to a product as fine as 5 µm. This paper discusses the performance of two inert grinding media used in the Isa Mills in Mount Isa Mines of Australia for processing galena and sphalerite bearing ores to below 10 microns. They are the copper reverberatory furnace slag (CRFS)and the heavy medium plant rejects (HMPR). A methodology was also demonstrated for comparing the medium performance and for scaling up the Isa Mills from a 1.5-litre laboratory batch mill to a full scale 3000-litre mill.

Jan 1, 2000

By A. M. Hearn, J. G. Roos

Energy consumption, being a large proportion of the input of the ferroalloy production process, can be measured in terms of the efficiency with which the energy is utilized and the effectiveness with which it is used. The efficiency of the usage of energy revolves around the specific consumption of the energy for the production of the alloy, which encompasses the thermodynamic aspects of the process and is more of a metallurgical function that will not be addressed further in this paper. The effectiveness with which the energy is utilized is determined by the optimisation of the electricity supply from the utility (in this case Eskom). The South African electricity supply industry is on the brink of considerable restructuring, implying changes in ownership, structure and regulation. In other countries, however, restructuring has often seen higher prices. Owing to the diversity of growth prospects in South African markets, Eskom is turning to new market management and generation strategies. In future, Eskom will develop pricing strategies to increase demand from attractive customer segments such as paper & pulp, iron & steel, aluminium, and other metallurgical industries. There will be a broader spectrum of product offerings, including dynamic pricing options and demand-side management incentives. In a future electricity market that will become more dynamic and demanding, it will become increasingly important for electricity consumers to optimise their electricity supply. There are many facets in optimising the electricity supply, which include optimal utilisation of the tariff, integrating energy cost management into the production planning process, implementation of demand-side management actions, modelling, scenario planning (.what-ifs?.), optimisation, maintenance scheduling coordinated with the tariff periods, etc. This paper gives consideration to the status of the development of technology at the manganese alloy works of Samancor at Meyerton, South Africa in order to increase the effectiveness with which energy is utilized.

Jan 1, 2004

By Varadajan Seshadri

Keywords: torpedo car, kinetics, physical modeling A 1:6 torpedo car physical model was built to assess the optimum refining conditions for pig iron desulfurization in the torpedo car considering the industrial parameters used in the steel plant CSBM (Companhia Siderurgica Belgo-Mineira, João Monlevade, MG, Brazil). The refining practice in this plant is through injection of a CaO-CaF2-Mg powder in the pig iron melt. Similarity between the model and prototype were established through Froude and turbulent Reynolds criteria. Mixing times were evaluated by pulse tracer addition and the kinetics of metal/slag interactions were assessed from experiments investigating iodine transfer from kerosene to water. The influence of parameters such as level of metal, gas flow rate, lance penetration, lance orientation were also evaluated.

Jan 1, 2005

By Marcel Vallée

Frequently, costs overruns and defaults in mining project performance result in serious problems and headaches for all project participants and impact on corporate objectives, profits and image and, occasionally, lead to project failure. As mining professional s, we should be very concerned that, in a recent World Bank paper (Weber-Fahr, 2001), geological and technical risks were considered the most important ones facing mining projects. Whenever we manage to reduce or minimize these risks, we are in better position to overcome the environment-, market-, finance- and community-related ones. The causes of this situation seem rather systemic, as a fairly long list of industry problems with new pro jects has been described in industry papers in pas t and recent years. A brief review of industry problems with mining projects will be given first, followed by a review of the basics of the current Quality Management and Continuous Improvement perspectives that have evolved from earlier quality control and quality assurance systems and policies. Particular particular attention will be given to the work of W. E. Deming. As the system approach is an essential part of such policies, it will be described succinctly. Given that poor communications and interactions among geologists, mineral processors and mining engineers/operators ca n seriously affect project efficiency and profitability, these interrelated processes with in the mining systems will be analyzed and modelled and the impacts of such situations will be described through a number of anonymous case histories and examples. A synthesis of Dr Deming's management system, includ ing his Four teen P oints and System of Profound Knowledge, will be prese nted .

May 1, 2002

By Mohsen Sanai, Paul Gefken

"SRI International has developed and patented* a castable dilute explosive tile @ET) that offersunique advantages over conventional high explosive. The primary advantages of DET are that itsdetonation pressure can be adjusted over a wick range and its impulse can be controlled independently by adjusting its thickness and configuration. Because DET has a much lower detonation velocity than conventional explosives, the pulse duration produced by DET is as much as 10 times longer than the pulse duration produced by conventional explosives for equal explosive weights. These features of DET present several advantages to the mining industry. For example, DET can be tailored so as to control fragment size and distribution to enhance extraction of desired elements from ore or breakup of specific regions."

Jan 1, 1995

By M. Shamsuddin

Information on total estimated uranium reserves and domestic requirements have been collected, A survey has been made on the possibilities of recovery of uranium from low grade and complex ore deposits, e.g., marine phosphorites, shales, coal, sea water, etc. In order to assess the potential for uranium recovery from uraniferous phosphorites, available thermodynamic data of uranium minerals, compounds and aqueous species have been collected. The existence of uranium complexes with chloride, fluoride, carbonate, phosphate, sulfate, etc., in ground waters have been evaluated at different pH's. There seems a great need to study the relative stability of these complexes in order to judge the applicability of solution mining technology for selective leaching of uranium from phosphorites. A typical flow-sheet demonstrating recovery of uranium from wet-process phosphoric acid has been included in this report. Some essential features of the economics of uranium recovery from uraniferous phosphorites have been briefly considered and recommendation have been made for further studies.

Jan 1, 1980

By M. K. Mohanty

One of the main objectives of this study was to evaluate a fine-coal cleaning circuit using an enhanced gravity separator specifically for a high sulfur coal application. The evaluation not only included testing of individual unit operations used for fine-coal classification, cleaning and dewatering, but also included testing of the complete circuit simultaneously. At a scale of nearly 2 t/h, two alternative circuits were evaluated to clean a minus 0.6-mm coal stream utilizing a 150-mm-diameter classifying cyclone, a linear screen having a projected surface area of 0.5 m2, an enhanced gravity separator having a bowl diameter of 250 mm and a screen-bowl centrifuge having a bowl diameter of 500 mm. The cleaning and dewatering components of both circuits were the same; however, one circuit used a classifying cyclone whereas the other used a linear screen as the classification device. An industrial size coal spiral was used to clean the 2- x 0.6-mm coal size fraction for each circuit to estimate the performance of a complete fine-coal circuit cleaning a minus 2-mm particle size coal stream. The ?linear screen + enhanced gravity separator + screen-bowl circuit? provided superior sulfur and ash-cleaning performance to the alternative circuit that used a classifying cyclone in place of the linear screen. Based on these test data, it was estimated that the use of the recommended circuit to treat 50 t/h of minus 2-mm size coal having feed ash and sulfur contents of 33.9% and 3.28%, respectively, may produce nearly 28.3 t/h of clean coal with product ash and sulfur contents of 9.15% and 1.61%, respectively.

Jan 1, 2008

By H Zimba, S Sondashi, M Chitambo

By the time a reagent is finally accepted by a mine for use on its plant it could have gone through several screening and evaluation stages. These stages may include laboratory and plant evaluation testwork. This paper outlines the steps that were followed to select, design and implement a frother for KONKOLA COPPER MINES PLC Nchanga Copper Concentrator in Zambia. It discusses initial frother screening work conducted at the Betachem metallurgical laboratory and the subsequent laboratory screening testwork conducted at Nchanga Concentrator. A modified Bikerman test method is discussed which was used to design a frother for the Nchanga flotation plant. The paper also gives an account of several plant scale trials conducted on Nchanga flotation plant and discusses the plant results, frother consumption patterns and some commercial concerns, before the product was finally accepted by the mine.

Jan 1, 2007

By David J. Kusler

This study is an appraisal of the feasibility of recovery and the possible chemical and physical uses of the limestone from the Greenbrier Formation in western West Virginia. Data on minability, occurrence, quality, and markets were obtained from published and unpublished sources and by a limited mail survey combined with personal contacts. The estimated costs of recovery by deep mining techniques are considerably higher than competitive surface and shallow subsurface operations. Compositional in formation available for this study was limited but indicated the suitability of the limestone for most physical uses and some chemical process uses in appraisal of the uses and demand reveals that immediate markets may be difficult to establish, but for some uses long-term prospects may be encouraging, especially if the quality of limestone would be suitable for lime manufacture or use as metallurgical fluxstone.

Jan 1, 1968

By P Knight, P A. Walker, H E. Speight

Pushback 8 South is the final cut back on the south wall of the East Pit at BHPBilliton?s Mt Whaleback iron ore mine in the Pilbara region of Western Australia. Development of the cutback commenced in 1999 and is now nearing completion with ultimate pit walls up to 300m high. This paper describes the geotechnical, structural and hydrogeological setting of PB8S, reconciliation between design and slope performance and the slope engineering techniques used to effectively manage the risks associated with the slope. These techniques include slope buttressing and sequential mining with waste backfilling, as well as a detailed program of displacement and hydrogeological monitoring, structural mapping and slope stability assessment. During the course of slope formation recent developments in remote slope displacement monitoring using radar and remote structural mapping using terrestrial photogrammetry have also been applied. Aspects of the PB8S slope management plan are relevant to many large scale open pit slopes. This paper provides geotechnical practitioners with information which may be helpful in managing geotechnical risk in similar environments.

Jan 1, 2006

By T. Bajpayee, J. Ellenberger

Microseismic monitoring and evaluation is one aspect of the National Institute for Occupational Safety and Health (NIOSH) research program. Roof falls are often preceded by a period of elevated microseismic activity, but not all periods of elevated activity result in a roof fall, nor do all roof falls occur after some amount of elevated activity. The objective of this study is to review periods of elevated microseismic activity and determine whether fracture activity rate can be used to anticipate the initiation of roof falls. The study was carried out at an underground limestone mine where major roof falls are associated with excessive horizontal stress. The progression of roof falls was detected by the microseismic signature produced by the rock falling from the mine roof onto the mine floor, which is termed a roof fall impact event. A total of nine elevated fracture activity periods that resulted in seven major roof falls were examined. It was observed that elevated fracture activity preceded the initial roof fall impact event in three out of four major roof falls. The initial impact event was not identified for the remaining three roof falls. Fracture event rates were analyzed and a roof fall alarm trigger of five fracture events in a ten minute time period was established for this test case. The fall alarm trigger was tested against six of the elevated activity periods. Four roof falls occurred in the six periods of elevated activity, and two would have triggered the alarm before the roof fall occurred, while two false alarms were generated. The results show that limited success would have been achieved by the microseismic system as a roof fall alarm trigger. However, the trigger would have been successful at warning of the onset of elevated activity, allowing mine employees to respond appropriately. The study highlighted some issues with implementing such a system in an operating mine, including the need for real time identification of fracture related microseismic signals among mining induced signals, and accurate location and identification of fracture clustering.

Objective To develop safety training tools for mine safety and health professionals that fill gaps in currently available materials. Background Over the past 4 years, NIOSH has developed and released a series of training videos targeted at underground mine safety. These videos were developed in close cooperation with the mining industry and safety training professionals and were intended to provide realistic, interesting, effective training to both new hires and experienced miners. The videos cover the mining cycle, starting with the breaking of the rock (Handling Explosives in Modern Mines), making certain the work area is safe after a blast (Rock Falls— Preventing Rock Fall Injuries in Underground Mines), installation of ground supports and recognition of failed supports (Miner Mike Saves the Day), and hauling both ore and materials in the mine (Hazards in Motion). A separate video (Hidden Scars) captures the story of a fatal rock burst through an interview with a miner who nearly died and who lost his partner in the accident. These videos have been extremely popular in the mining industry and are being used across the nation as well as in 18 other countries. Two of them, Rock Falls and Miner Mike Saves the Day, have won Alice Hamilton awards, NIOSH’s highest recognition for Excellence in Occupational Safety and Health, in the Educational Materials category. Approach A recently completed independent evaluation of the SRL mining videos identified five themes that mine safety trainers consider necessary for successful training materials: high quality, credibility, accurate content, effectiveness, and an engaging nature. All of the NIOSH videos were rated very high for each theme. Using these measures of effectiveness, a more difficult challenge has been undertaken. Much has been written in the mining industry about the coming turnover in employment. The average age of miners in the United States is approaching 50, and many of the “experts” will be leaving the industry as they reach retirement age. The mining industry, like many industries involving skilled labor, relies heavily on a master-apprentice relationship between new hires and older miners. New hands learn from experienced miners. Their learning falls into three primary categories—they learn what’s important to know, they learn how to do things correctly and safely, and they learn the culture.

Mar 1, 2002

A clear understanding of the meanings of terms is important when discussing a project. Whether it is a submission, an investment study, a feasibility study, an environmental impact statement, an estimate, a tender, a contract, or a close-out.report, the need for all parties involved to understand what is under discussion or what has been written is paramount. The clarity of definition and the level of understanding can affect the outcome of the project. It is vital that all parties know what is wanted, what is expected, and what it will cost. This paper draws attention to some of the problems that beset many projects, clients, project managers and contractors, and it is hoped that its presentation will encourage us to pay more attention to defining what it is that is required. Ultimately we should all be the richer for having defined and understood the requirements at the beginning rather than at the end.

Jan 1, 1990

By Charles Sabine

The U.S. Bureau of Mines studied mines and prospects in the Bristol/Granite Mountains Wilderness Study Area (WSA) in 1982. The 45,000 acre WSA, located in the eastern Mojave Desert of California, is underlain by Mesozoic plutonic rocks with scattered roof pendants of Paleozoic (?) metasedimentary rocks. Two mines and six prospects are identified; one mine, the Silver Lode Mine, and a prospect of unknown name are adjacent to the area. The Silver Lode Mine has occurrences of silver, lead and zinc. Within the study area, the Comanche Mine has occurrences of iron and copper and the Iron Victory Prospect has an occurrence of iron. None are large enough to constitute a resource. Occurrences of magnesian marble at the Comanche Mine, Iron Victory Prospect, and elsewhere in the area contain too much MgO for commercial use other than agricultural soil supplements or crushed stone. Transportation costs to markets would exceed the value of the rock. At the Comanche Mine, situated in a roof pendant of marble, about 10 tons remain of a 110-ton pod of magnetite which contained 42.5% iron, and less than 50 tons remain of a mineralized fault breccia which averaged 2.5% copper and 0.3 oz/ton silver. Magnesian marble contained 41 to 45% CaO and 14 to 16% MgO. Primary and secondary silver, lead, zinc, and copper minerals are disseminated along altered joints and in quartz veins in quartz monzonite at the Silver Lode Mine, adjacent to the WSA. Analytical data are sporadic; samples contained as much as 0.12 oz/ton gold, 1.8 oz/ton Silver, 1.1% lead, 3.8% zinc, and 0.3% copper. Mineralized zones in the workings are not resources, but they might indicate possible silver-lead-zinc resources at depth. At the Iron Victory Prospect, lenses of magnetite and hematite with some chalcopyrite occur in a skarn lone in a marble roof pendant. About 110,000 tons of iron-rich rock, averaging 47.2% iron, are present; the largest lens contains about 30,000 tons. About 150,000 tons of magnesian marble, averaging 41.0% CaO and 11.7% MgO, are also present. Deposits of stone, and sand and gravel in the WSA are too distant from markets to be resources. Occurrences of energy minerals were not identified.

Jan 1, 1984

By C Jia, J Graindorge, L M. Olssen

Picking up abandoned mining tenements and looking to recover remnant resources around old operations is an opportunity that comes with its own challenges and risks. Reliance on information released to government departments (such as the Department of Mines and Petroleum (DMP) in Western Australia) by the previous owners, can compound the risk.This paper explores Alto Metals Ltd’s Lord Nelson and Lord Henry deposits and surrounds near the town of Sandstone in Western Australia. The Lord Nelson and Lord Henry open pits produced around 2 Mt of ore for over 250 koz of gold during production between 1999 and 2010. There has been no further work carried out in the area between 2010 and 2016. The deposits are open at depth and along strike.Alto Metals picked up the tenements in 2016 and has subsequently re-estimated remnant resources around Lord Nelson and Lord Henry, and publicly reported updated Mineral Resources in accordance with the JORC Code 2012.All of the information was manually compiled from data released to the DMP and annual reports. This paper highlights the challenges and risks arising from this data compilation, geological interpretation, re-estimation and classification process, together with future opportunities and challenges for further developing the area.CITATION:Olssen, L M, Graindorge, J and Jia, C, 2017. Starting from scratch – defining remnant resources from publicly available data: a case study from the Lord Nelson and Lord Henry gold deposits, in Proceedings Tenth International Mining Geology Conference 2017, pp 175–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By F. Calizaya

The PT Freeport Indonesia‘s Deep Ore Zone(DOZ) copper deposit is located in the province of Irian-Jaya, Indonesia. Currently, a block cave mine is being developed around this deposit. Production is scheduled to start in year 2000 and to ramp up to25,000 tpd by year 2003. The air quantity requirement for this mine is equal to 780 m3/s. To supply this quantity, the mine will require five centrifugal fans (one 450 and four 750 kW fans). This study summarizes the technical aspects related to the installation and commissioning of one of these fans. The fan was installed on the surface in a parallel arrangement with two others. It has a design capacity of 240 m3/s of air at 2.2 kPa of static pressure. The study presents the installation details from the underground shaft excavation and portal development through fan testing and commissioning. It also presents the results of a monitoring system that was installed to determine the fan duties.

Jan 1, 2000