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By Peter White

Mine Planning Shaft Collar Shaft Sinking Raises Ramp Underground Water Storage

May 1, 2009

By Caithness SJ, Heape JMT

Following the discovery by CRA of gold at Mt Kare, and the subsequent 1988-90 gold rush, mechanised mining of the alluvial resource is now being carried by a company jointly owned by CRA (51%) and landowners of the area (49%). Mining is currently being carried out using small gravity processing plants fed by hydraulic excavators. Use of hydraulic mining techniques will be limited to over- coming difficulties related to the high clay content of the material and the soft nature of the bedrock. Current resource estimates suggest that the alluvials will have a mining life of three to four years. During this time, exploration of the hydrothermal gold mineralisation at Mt Kare will be carried out by a wholly-owned company of CRA. It is hoped that this will lead to establishment of an economic primary gold resource.

Jan 1, 1991

The profitability of gold placer mining operations is determined by more factors than many placer miners recognise until too late. This study is based upon field trips to examine the efficiency of mining and transportation of gravels to a wash plant by bulldozer and truck. At the examined open pit mining operations gravels were washed using water canons, derockers or scrubber trommels. The objective of this study was to determine the relationship between unit costs and power requirements for gravel mining and processing. The author conducted a number of time and motion studies at four open pit gold mines, including the Maly Patom Creek, the Nizhny Patom, the Taimendra Creek and the Kadali-Makit in the Bodaibo District, Irkutsk Region and collected and processed field data. As a part of the study significant correlations were determined and empiric regression equations derived between: power requirements (Ep) and unit cost (Cp) for gravel processing; and total power requirements (Et) and total unit cost (Ct) for gravel mining, transportation and processing. Based on the results of the study it was proposed to modify the current mining procedure methods and to replace water cannons at the Maly Patom Creek with a PPM-5 derocker. Introduction of the proposed technology resulted in 2004 in US$385 000 mining cost reduction at the Maly Patom Creek over a short-time Siberian mining season.

Jan 1, 2007

By Martin Nevens

"In 1998, the Iron Ore Company of Canada initiated an aggressive program to improve the performance of its Carol Lake Concentrator located in Labrador City, Newfoundland. This program was termed the Concentrator Upgrade Program. The Concentrator Upgrade Program was a group of initiatives developed with the common goal of improving the overall process and operations of the IOCC Carol Lake Concentrator. The main goal of the program was to increase the annual production capacity of the concentrator from 18.0 million tomes to 21.6 million tomes. This gain in capacity was to be done mainly through improvements in process iron recovery. The target iron recovery value was 80+% versus a historical value of 70%. This improvement in iron recovery would translate to a natural weight recovery improvement from 44% to 50%.The Concentrator Upgrade Program provided the first opportunity in 30 years to make fimdamental changes to the concentrator flowsheet. To accomplish this, several pilot plants were built to evaluate new circuits. AAer 2 years, a new flowsheet was selected for the primary gravity separation circuit and the magnetite circuit. The centrepiece of the new flowsheet was the introduction of Hindered Settling Separators to the metallurgical process.The Concentrator Upgrade Program has since proceeded into detailed engineering and, as of February 2001, construction. The first one of IOCC’s 3 primary AG Mills (Mill 11) has been converted to the new flowsheet at the time of writing and is in the throes of commissioning. This paper will review the flowsheet development program in the pilot plant for the gravity separation circuit and examine the overall benefits to the operation of the IOCC Carol Lake Concentrator."

Jan 1, 2002

By Seffen Leppla, Rolf Katzenbach, Matthias Seip

"Abstract The economic and safe design of deep foundation systems in difficult soil conditions is based on a reduction of construction material used, construction time spent, energy consumed and a high-level modelling of the soil-structure-interaction. The special foundation system Combined Pile- Raft Foundation (CPRF), in-situ load tests on the construction site and a sufficient soil investigation allow cost optimised constructions. In any case at challenging projects the observational method has to be applied for verification and quality control of the design. Regarding the 4-Eye-Principle as basis of the quality control management an independent peer review of the planning, design and construction phases is the guarantee for safety, serviceability and optimisation of all projects. Main execution standards for the construction of deep foundations based on the Eurocode 7 are summarised and discussed. The paper presents the basics of the safe and qualified design and construction of foundation systems including quality assurance. The application in engineering practice is shown on achallenging project of high-rise buildings with difficult boundary conditions.IntroductionThe construction of deep foundation elements in inner cities are special challenges due to the limited space for the construction works and the effects on existing buildings (Figure 1).An economic and safe design of deep foundation systems in difficult soil conditions is based on the following main aspects:•,qualified experts for planning, design and construction•,interaction between architects, structural engineers and geotechnical engineers•,adequate soil investigation•,design of deep foundation systems using the Finite-Element-Method (FEM) in combination with•,enhanced in-situ load tests for calibrating the soil parameters used in the numerical simulations•,quality assurance by an independent peer review process (4-eye-principle) combined with theobservational method if necessary"

Jan 1, 2014

By William Babcock

Augered, Cast-In-Place (ACIP) piles can be an economical, reliable, versatile foundation system. They have also been a part of projects that were behind schedule and the subject of lawsuits. The ACIP pile is a specialty system that is more workmanship dependent than most deep foundation systems and is especially vulnerable to the problems and abuse of poor specifications and contract language. Many of the original specifications were based on grouting methods, and numerous misconceptions have followed the method. The Deep Foundations Institute (DFI) has been the leader in debunking the mystique that has hovered over the method and attempted to standardize the industry through publication of the manuals describing the method and how it should be inspected. DFI should be applauded for taking the lead and producing a reference document that can be used to educate the specification writers, designers, inspectors, and owners. It must be must appreciated that there have been other organizations that would not acknowledge ACIP piles as a legitimate member of the deep foundation family. Some consultants and designers have gone to the extreme of making it policy to not recommend the method for use. This presentation is one practitioner's view of the causes of problems as they can be traced back to the contractual conditions. It is intended to provide a broader and different perspective than those provided by the technical specialists. It does not necessarily reflect the position of the DFI or any of the organizations associated with the ACIP pile industry. It is intended to further the spirit of partnering on every ACIP pile project, to further the acceptance and promote the use of this unique system, for the benefit of all the parties. It should be recognized, however, that all of the participants can and do play a role in getting a project into trouble. My view is that projects that get into trouble usually have an early flaw that leads the project to the edge, and the project participants blindly follow the original mistake right over the cliff like lemmings. This instinctive reaction may be a survival tactic by going along with the group, because any one party that departs from the program or shows a position of weakness is a candidate for sacrifice.

Jan 1, 1997

By L. Hanschar, C. Bwalya, E. Mokola, K. Musonda, A. Makayi

This paper describes the installation, commissioning and operation of porous plugs featuring nitrogen gas purging in both Anode Furnaces at the Kansanshi Copper Smelter (KCS), a greenfield copper smelter which commenced operation in March 2015. The decision to install porous plugs was taken in November 2016 and the facilities were successfully commissioned on both anode furnaces in October 2017. The project was successful and has demonstrated the following process improvements: 12.2% reduction in main burner fuel consumption Larger average charge size, due to fewer accretions; 17 minute decrease in average refining cycle times Improvements in slag skimming operations Improved casting rates INTRODUCTION Porous plugs The application of porous plug technology in copper smelter anode furnaces is well established around the world. Vukovic and Gamweger (2017) and Wallner (2004) noted that the stirring and mixing action induced by the injection of inert nitrogen gas into the molten copper via porous plugs has potential benefits in the following areas: Homogenization of the temperature and composition of the molten copper resulting in Reduced fuel consumption Less tendency to overheat slag (reduced risk of refractory attack) Less slag produced with a lower degree of oxidation (lower rate of refractory wear) Less tendency for buildups to form Improved environmental performance (produce low sulphur blister at Peirce Smith converters) Elimination of buildups inside the furnace and potential for larger charges per cycle Reduced processing times and potential for shorter cycle times More efficient skimming of anode slag Shorter skimming time Less copper carry over to Peirce Smith converters Very little slag remaining in the furnace (reduced potential for buildups to form)

Jan 1, 2019

By Miguel Pimentel

El presente trabajo describe el proceso implementado por la minera Yanacocha para el tratamiento de las aguas de exceso a través de la Tecnología de Membranas (EMS- Engineered Membranes System) o proceso de Osmosis Inversa, conocida también por las siglas en inglés de RO (Reverse Osmosis). El proceso RO tiene por objetivo tratar la solución barren proveniente de la planta de Merrill-Crowe para reducir el contenido de cianuro, así como los metales disueltos y otras sustancias como nitratos y nitritos en la solución.También, busca clarificar el agua tratada para cumplir con las exigencias que establece el Ministerio de Energía y Minas (MEM) y el Banco Mundial (IFC) en cuanto a límites de descarga permisibles. Una vez alcanzados los niveles establecidos, y con la aprobación del área interna de Control de Calidad, el agua tratada se descarga al medio ambiente.

Sep 12, 2005

By Gregory M. Molinda

Historically, miners have known that roof rocks originally composed largely of mud were prone to slaking and deterioration when exposed to water and humidity. Mine Safety and Health Administration (MSHA) records show that roof falls are more prevalent in summer and late fall. Field data shows higher bolt loads and increased room convergence in summer months. Laboratory data shows that very high internal pressures can be generated by significant strain in clay-rich rocks. In summer months humidities ranging from 70-100% can cause rock strains up to 7%, and rock pressures of 14,000 psi, more than enough to break apart weak shales and fireclays. The National Institute for Occupational Safety and Health (NIOSH) conducted wet/dry immersion cycling of clay-rich rocks. Results show that the rocks most prone to moisture deterioration are fireclays, claystones, and sandy shales, all of which have disrupted bedding. Of the 7 mudrocks with a weatherability index above 40%, none showed consistent fissile bedding. Black shales were surprisingly resistant to wet/dry water immersion cycling. Generally, mixed rocks (stackrock), typically susceptible to horizontal stress, are more resistant to moisture-deterioration. Mine roof rocks tested with moisture sensitivity ratings above 50% (moisture sensitivity index ranges from 0-100 with 100 being the most sensitive) all came from mines which had roof skin problems and used supplemental support to prevent rock fall injuries. Some roof rocks showed lateral variability of moisture sensitivity values, suggesting the need for more samples in highly varying roof rocks. Swelling strains of mudrocks showed that almost all of the swelling occurred in the first 24 hours after immersion. The wet/dry immersion cycling test used provides an accurate, quick and inexpensive method for estimating the moisture sensitivity of mudrocks. With this information mine operators can begin to anticipate hazardous ground and prepare appropriate roof support.

Jan 1, 2006

By O. C. Blade

Diesel fuel is being used in greater volume than ever before in the United States. During 1950 railroads used 43 percent of the total volume of Diesel fuel sold, smelters, mines, and manufacturing plants used about 13 percent, highway vehicles such as trucks and busses, and equipment such as tractors and bulldozers accounted for approximately 20 percent, about 12 percent was used by water craft, and the remaining 12 percent by gas and electric utilities, the military forces, and oil companies. These figures were calculated from data issued by the Bureau of Mines. 2/ Comparable figures for 1951 and for 1952 to date are not available, but recent information indicates that well over 11,000,000 barrels of Diesel fuel per month are produced by the country's refineries. 3/ More information on this increasingly important type of engine fuel is needed by the petroleum industry, engine manufacturers, and consumers, particularly on the grades and qualities of the Diesel fuels being marketed. To supply this information the American Petroleum Institute and the Bureau of Mines, United States Department of the Interior, under cooperative agreement, are conducting annual surveys of Diesel fuel oil produced in refineries in this country.

Jan 1, 1952

By T. A. Muhlare

"Large quantities of slag are produced every year and dumped on slag heaps around the world, posing a potential environmental threat due to contained heavy metals content. Slags are waste minerals produced during furnace smelting of minerals. The contained values of base metals may be released into the environment under natural weathering conditions polluting ground and underground water. Copper losses into slag are a continuous problem in pyrometallurgical smelting operations. Due to shortage of ore concentrate, various mining operations have initiated the recovery of copper from dumped slag. The typical process uses crushing, milling and flotation. These operations create excessive liner wear rates during crushing and milling because the bond work index of copper slag is 22 kWh/t and this is considered a very hard slag. The process also has reduced flotation recoveries and requires high flotation reagent consumption. The present work shows that digestion of the milled copper slag slurry with concentrated sulphuric acid at a temperature of 250oC forms a solid cake and leaching of the solid cake with water is a possible option. However, the consumption of sulphuric acid can have a considerable cost on the recovery process. This can be limited by producing a leach residue containing gypsum and silicate materials as amorphous silica which are suitable for use as an additive for Portland cement. Laboratory results show that 90% copper recoveries can be achieved. The leaching is conducted to prevent silica gel formation and iron co-extraction. Leaching is optimum if silica gel-free solutions and good filterable residue are obtained. INTRODUCTION Slag is a waste by-product of smelting and converting operations in metallurgical plants. Both smelting and converting operations are aimed at iron separation from base metal sulphides in non-ferrous metallurgy. The iron sulphide component of the ore or concentrate is oxidized to iron oxide at higher temperatures in the molten form, and then fluxed with silica and other oxide rock minerals to produce fayalite (2FeO•SiO2) slag (Schlesinger et al., 2011). Slags are generally deposited on dumps and considered to be unreactive materials. Smelter copper slag contains significant concentrations of several potentially toxic elements, including arsenic, lead, cadmium, barium, zinc and copper. These elements can be released into the environment under natural weathering conditions and cause pollution of soils, surface waters and groundwater (David, 1998)."

Jan 1, 2015

By A. Muwila

Hercules? is a low nickel austenitic stainless steel developed at Mintek that has a typical composition of 9 wt% Mn, 0.05 wt% C, 2wt% Ni, 0.25 wt% N and 16.5 wt% Cr. A more corrosion resistant version of Hercules? (Hercules? B) with 0.5 wt% Mo has also been developed. Potentiodynamic tests performed on Hercules? B in a 5wt% sulphuric acid solution showed it to have improved corrosion resistance comparable to that of AISI 304. The effect of a varying Mn content on the corrosion resistance of Hercules? B has also been investigated and the results discussed in this paper. From the corrosion test results, it is clear that decreasing the Mn content of Hercules? B increased the corrosion rate, while increasing it decreased the corrosion rate. Keywords: austenitic stainless steel, % ferrite, molybdenum, manganese, nitrogen, electrochemical corrosion tests, potentio-dynamic scans, microstructure, chemical analysis.

Jan 1, 2007

By M. Pernot

A 12 m-deep excavation has to be perfomed in the Shanghai soft clay to install an underground electric substation. This article was originally intended to study the behaviour of the wall, the excavation bottom and the surrounding ground during the excavation. Since the works are behind schedule, and the data referring to the excavations are not, therefore, available, the article is limited to a presentation of the analysis methods that we envisaged for the study of the behaviour of the excavation.

Jan 1, 2010

By Paulo José Costa Couceiro Junior, Manuel Lopez Cano

The biggest Port of Latin America - the Santos Port in São Paulo, Brazil - has been drilled and blasted by controlled underwater techniques in order to remove around 40,000 m3 (52,318 cubic yard) of rock divided in two outcrop rocks: Teffé and Itapema. Underwater pumped explosive, in combination with small cartridges areas, was successfully used in order to reach a target depth of -15m (-49 ft) and a width of 220m (722 ft) in the navigation channel. It was the first time that a pumped explosive was used in underwater blasting in Brazil and it represents a historic benchmark for projects of this kind in this country. The main challenges faced in this project include the control of the ground vibration, due to the necessity to carry out detonations 40m (131 ft) away from the quay wall - where the passenger terminal and the 80 year-old warehouse were located – and the rush schedule available, in order to finish the underwater drilling and blasting phase before the coming cruise season. Therefore, the perfect combination of an ideal pumped product with an effective pumping system has permitted to carry out the project in a record of less time than 3 months (against to the original expected time of 18 months), with all vibration events under control as result of the special ground vibration program carried out.

Jan 1, 2016

By J. L. Gillson

Joseph H. Birman (Chairman, Dept. of Geolcgy, Occidental College, Los Angeles, Calif.) Many thanks to J. L. Gillson for so comprehensive a survey of the titanium sand deposits of the world. Over the past two years, the writer studied rather carefully some of the Cretaceous ilmenite deposits in New Mexico and Colorado, including the Sanostee deposit shown in Gillson' s map, Fig. 6. The deposits were geologically mapped and sampled, surveyed by magnetometer, and the Sanostee deposit was drilled. Moat of the genetic interpretations made by Gillson concerning the recent sedimentary ilmenites can be clearly read in the Cre-taceous deposits in New Mexico. The deposits are in marine regressive members of the Mesaverde group. The deposits trend within a few degrees of N 55° W and persistence of this trend through both distance and time (the deposits are in different members of the Mesaverde group) implies that the deposits are offshore bar accumulations. Heavy mineral content ranges from about 10 pct to more than 50 pet. Thicknesses are from 4 ft to as much as 20 ft, widths range from 150 to 600 ft, and lengths range from a few thousand feet to a few miles. All are locally or completely overlain by carbonaceous shale and thin coal. The deposits are strongly altered, and from X-ray diffraction the principal titanium alteration product appears to be anatase. Drilling of the Sanostee deposit shows that the alteration is not related to the present erosion surface but took place at the site of deposition and before burial by the overlying sediments. Iron oxide derived from the alteration cements the grains and is the chief coloring agent in the immediately overlying shales. In the Sanostee deposit, there is virtually no feldspar, the gangue mineral being almost exclusively quartz. Sorting is excellent, but the quartz grains are subangular to angular. Petrographic examination reveals that the angularity is not due to overgrowths. Therefore, short distance transport is implied. The mineralogical composition suggests a low relief granitic terrane as the source area. Feldspar may have been decomposed by weathering at the source, but an alternative preferred by the writer is that each of the deposits represents a long-term concentration site (for example a large sand bar) which was continually being deprived of light minerals by wave action and selective transport. Feldspar may have been mechanically reduced in size more quickly than the quartz, and thus its rate of removal may have exceeded that of quartz. Concentration of heavy minerals would thus occur until the marine regression removed the zone of maximum wave energy from the site. Chemical alteration would then become the most important process until burial by encroaching swamp deposits.

Jan 1, 1961

By D. Bessinger, J. Nell

The electrical conductivity of rutile was optimised as a function of time, temperature and gas composition. These optimised conditions were used to treat rutile/zircon feed prep concentrate samples from a South African heavy minerals producer, prior to electrostatic separation. Enhanced separation between rutile and zircon was obtained when compared to untreated samples. Samples treated in a hydrogen atmosphere and cooled in nitrogen showed the best separation when passed through a high tension electrostatic separator using conditions of high sample temperature and high relative humidity.

Jan 1, 2005

By Mohammed Sakr

This paper presents the results of a full-scale axial compression and tension (uplift) testing program executed on large-capacity helical piles installed in very stiff to very hard clay till soils (i.e. cohesive soils). A total of ten tests including six axial compression tests and four tension (uplift) tests were carried out. The results of the axial compressive and tensile pile load tests and field monitoring of helical piles with either a single helix or double helix are presented in this paper. Helical piles are traditionally used to support light to medium loads (i.e. loads up to 500 kN or 56 tons). However the results of the present study confirmed that helical piles can support significantly higher axial compressive loads up to 2450 kN or 275 tons, which is about 5 times traditional design loads. The study also demonstrated the high tensile capacities of helical piles which was as high as 85% of their compressive capacity. Hence helical piles can provide a viable design option for foundations supporting relatively heavy loads.

Jan 1, 2012

By J Wallis

The stability of a raise bore is often assessed using the rock mass classification system published by McCracken and Stacey as a modification of the Q system. Often the assessment is done using a spreadsheet to manipulate geotechnical log(s) of boreholes. This paper discusses the inherent difficulties with this approach. Recent work by others to provide guidelines to the classification system is discussed. A recent example of the design and raise bore performance at Macraes Gold Mine, New Zealand is presented. A key issue is that a visual assessment of the drill core and/or core photographs is necessary to æground-truthÆ the classification.

Jan 1, 2008

By B. Burke, R. Colquhoun, K. Thomas, R. Walton, D. Fentie

The new Roasting Facility at Barrick’s Goldstrike Mine in Nevada, U.S.A. was developed to process 12,000 tons per day of refractory gold ore. The process consists of crushing, dry grinding, roasting, extensive gas purification, calcine quenching and leaching in the presence of activated carbon. The new plant is integrated into the existing Goldstrike facility, treating ore from both open pit and underground sources. The process design, procurement, construction and commissioning of the Roaster facility was performed successfully over a 3½ year period with peaks of 400 engineering personnel and 950 construction personnel supporting the project. The US$330,000,000 project was completed ahead of schedule and under budget. The commissioning was well planned and proceeded smoothly through a rapid start-up to achieve all primary goals within three months of the start of processing of ore.

Jan 1, 2001

By Jacob Masliyah, Zhiang Zhou, Tshitende Kasongo, Jianjun Liu, Zhenghe Xu, Jeawon Choung

"Slime coating is a recognized challenge in fine particle flotation, not only in decreasing recovery, but also in reducing the selectivity and hence froth quality. In this presentation, a novel method based on electrophoretic mobility distribution measurement to study slime coatings is described. By measuring electrophoretic mobility distribution of individual minerals and their mixtures, the interactions between these minerals can be evaluated.For illustrative purposes, a model system of fine coals, or oil sands with two different types of fine clays was studied. Flotation tests showed a significant decrease in coal (bitumen) flotation recovery with montmorillonite but not with kaolinite clay addition. When electrophoretic mobility distribution of a fine coal/montmorillonite clay mixture was measured, a single modal zeta potential distribution was obtained, in contrast to a bimodal distribution for fine coalkaolinite clay mixture. This finding suggests a stronger adhesion of montmorillonite than kaolinite clays on fine coal surfaces. In the case of bitumen, the bimodal zeta potential distribution was measured for the mixture of bitumen emulsion and kaolinite or montmorillonite, indicating a weak attraction of the clays by bitumen. In the presence of calcium, however, a single modal zeta potential distribution was obtained in the mixture of bitumen emulsion with montmorillonite but not kaolinite clays. These findings are in excellent agreement with bitumen flotation results, demonstrating that the electrophoretic distribution measurement is a powerful tool to study slime coating phenomenon in a complex fine particle flotation system."

Jan 1, 2002