Search Documents

By D. Ling, Santos. R. M., T. Van Gerven, M. Guo

The valorization of alkaline waste materials from thermal processes utilizing intensified mineral carbonation routes is investigated. The principal advantages of this approach are the chemical stability and storage safety of mineral carbonates, the opportunities for process integration presented by the technology, and the potential for conversion of low-value materials into useful products. Treatment and disposal of steel slags are a costly burden on steel plants. Sustainable solutions for Argon Oxygen Decarbonisation (AOD) and Continuous Casting (CC) stainless steel slags and Basic Oxygen Furnace (BOF) steel slag are desired. An integrated on-site mineral carbonation approach is envisaged as a favourable solution.

Jan 1, 2011

By T. G. Carter

"Damaging seismicity associated with deep faulting in both mining and civil excavations not infrequently occurs without warning, and often before proper mitigation measures have been put into place. Severe squeezing is also a common problem for excavating through deep major faults. While both problematic conditions are difficult to predict and characterize, there is often a need at pre-feasibility and feasibility level to more reliably estimate the possible level of risk posed by such geologic structures. This paper introduces some structural geologic techniques that have potential application for both mining and civil applications for aiding forewarning of the extent of these types of problem.INTRODUCTIONEncountering adverse faulting at depth in deep excavations, whether for mining or civil purposes can create serious economic and safety impacts. For deep mines or for deep tunnel projects, measures are available for aiding prediction of the extent of possible influence that large scale faults could create, but these techniques are rarely if ever applied as part of routine site investigation programs, or even as part of risk assessment evaluations. Several well established structural geologic methods of palao-history reconstruction have potential application for aiding forewarning of the extent of these types of potential problem by allowing estimates to be made of:• controlling stress orientations that might engender reactivation movement;• principal stress magnitudes that could lead to failure initiation, and• probable mechanisms of fault deformation - brittle (bursting) or plastic (squeezing).This paper explores several structural geological and rockmass characterization techniques that have application for unravelling fault structure of importance to deep engineering projects. Their application for mining or tunnelling purposes is advocated in conjunction with conventional rockmass characterization assessment approaches using GSI, RMR and/or Q to aid early recognition and definition of potential adverse ground condition behaviour associated with intersection of significant faulting at depth."

Jan 1, 2015

By J. Esson, R. A. D. Pattrick, M. K. Nimfopoulos, D. A. Polya, K. M. Michailidis

"Economic Mn-oxide ore deposits of commercial grade occur in the Rhodope massif near Kato Nevrokopi in the Drama region, Northern Greece. The Mn-oxide mineralization has developed by weathering of continental hypogene rhodochrosite-sulphide veins. The vein mineralization is con-?ned by tectonic shear zones between marble and metapelites, extending laterally into the marble astabular, pod or lenticular oreshoots (up to 50 m x 20 m x 5-10 m). Supergene oxidation of the hypogene mineralization led to the formation of in-situ residual Mn-oxide ore deposits, and secondary infills of Mn-oxide ore in embryonic and well developed karst cavities.Whole rock geochemical pro?les across mineralized zones con?rm the role of thrusts and faults as solution passageways and stress the importance of these structures in the development of hydrothermal and supergene mineralization at Kato Nevrokopi. Three zones are recognized in the in-situ supergene veins: (A) a stable zone of oxidation, where immobile elements form (or substitute in) stable oxide mineral phases, and mobile elements are leached; (B) a transitional (active) zone in which element behavior is strongly in?uenced by seasonal ?uctuations of the groundwater table and variations in pH-Eh conditions; and (C) a zone of permanent ?ooding, where variations in pH-Eh conditions are minimal. Zone (B) is considered as the source zone for the karst cavity mineralization. During weathering, meteoric waters, which were CO2-rich (PCO2~10-3.8 to 10-1.4) and oxygenated (fO2~10-17 for malachite), percolated downward within the veins, causing breakdown and dissolution of sul?des and marble, and oxidation of rhodochrosite to Mn-oxides. Karst cavity formation was favored by the high permeability along thrust zones. Dissolved Mn2+was transportedinto karst cavities in reduced meteoric waters at the beginning of weathering (pH~4-5), and as Mn(HCO3)2in slightly alkaline groundwaters during advanced weathering (pH~6-8). Mn4+-oxide precipitation took place by fO2increase in ground waters, or pH increase by continuous hydrolysis and carbonate dissolution. In the well developed karst setting, some mobility of elements occurred during and after karst ore formation in the order Na>K>Mg>Sr>Mn>As>Zn>Ba>Al>Fe>Cu>Cd>Pb."

Jan 1, 1997

By J. Esson, R. A. D. Pattrick, M. K. Nimfopoulos, D. A. Polya, K. M. Michailidis

"Abstract-Economic Mn-oxide ore deposits of commercial grade occur in the Rhodope massif near Kato Nevrokopi in the Drama region, Northern Greece. The Mn-oxide mineralization has developed by weathering of continental hypogene rhodochrosite-sulphide veins. The vein mineralization is confined by tectonic shear zones between marble and metapelites, extending laterally into the marble as tabular, pod or lenticular oreshoots (up to 50 m ?? 20 m ?? 5-10 m). Supergene oxidation of the hypogene mineralization led to the formation of in-situ residual Mn-oxide ore deposits, and secondary infills of Mn-oxide ore in embryonic and well developed karst cavities.Whole rock geochemical profiles across mineralized zones confirm the role of thrusts and faults as solution passageways and stress the importance of these structures in the development of hydrothermal and supergene mineralization at Kato Nevrokopi. Three zones are recognized in the insitu supergene veins: (A) a stable zone of oxidation, where immobile elements form (or substitute in) stable oxide mineral phases, and mobile elements are leached; (B) a transitional (active) zone in which element behavior is strongly influenced by seasonal fluctuations of the groundwater table and variations in pH-Eh conditions; and (C) a zone of permanent flooding, where variations in pH-Eh conditions are minimal. Zone (B) is considered as the source zone for the karst cavity mineralization. During weathering, meteoric waters, which were CO2-rich (PCO2 ~10-3.8 to 10-1.4) and oxygenated (fO2 ~10-17 for malachite), percolated downward within the veins, causing breakdown and dissolution of sulfides and marble, and oxidation of rhodochrosite to Mn-oxides. Karst cavity formation was favored by the high permeability along thrust zones. Dissolved Mn2+ was transported into karst cavities in reduced meteoric waters at the beginning of weathering (pH~4-5), and as Mn(HCO3)2 in slightly alkaline groundwaters during advanced weathering (pH~6-8). Mn4+-oxide precipitation took place by fO2 increase in ground waters, or pH increase by continuous hydrolysis and carbonate dissolution. In the well developed karst setting, some mobility of elements occurred during and after karst ore formation in the order Na>K>Mg>Sr>Mn>As>Zn>Ba>Al>Fe>Cu>Cd>Pb."

Jan 1, 1997

By R. Agius, A. Nacu

"Cyanide destruction technologies are implemented at gold and silver operations to comply with the International Cyanide Management Code and meet ever more stringent discharge limits. Currently, the most common chemical cyanide destruction processes used in industry are sulfur dioxide/oxygen, hydrogen peroxide, and Caro’s acid. The cyanide destruction process used at an operation must reliably generate streams of acceptable quality at all times, and depends on numerous factors, including permit discharge requirements, tailings chemistry, location, site-specific climatic conditions and size of the operation. Selecting the most appropriate cyanide destruction process and determining the process design criteria requires accurate laboratory testing. This paper presents and discusses the results of a number of cyanide destruction evaluations that have been conducted to reduce cyanide concentration in process solutions or cyanidation tails. Laboratory testing provides important insights into reagent consumption and other factors required to achieve the target residual weak acid dissociable cyanide (CNWAD) levels.INTRODUCTION Process solutions associated with the extraction of gold and silver contain several forms of cyanide. The most toxic form of cyanide is free cyanide, which can be present as a dissociated cyanide anion (CN-) or gaseous or aqueous HCN. Weak or moderately stable cyanide complexes such as those of zinc, copper and nickel are classified as weak acid dissociable (CNWAD). Although less toxic than free cyanide, weak acid dissociable cyanide complexes are considered “ecologically sensitive” forms of cyanide and are regulated in most jurisdictions. In practice, reported WAD cyanide values comprises both free cyanide and weak acid dissociable cyanide complexes. Cyanide complexes with gold, mercury, cobalt and iron are referred to as strong acid dissociable complexes (CNSAD) and are much more stable, even under mildly acidic conditions. Another term commonly used in cyanide chemistry is total cyanide, which represents all cyanide compounds present in solution. Total cyanide levels in solutions are always equal to or higher than WAD cyanide values and the difference between the two usually indicates the presence of iron-cyanide compounds. Typically in Canada, CNTOTAL levels cannot exceed 1 mg/L in solutions discharged to the environment."

Jan 1, 2017

By Kenneth L. Graham

Horizontal directional drilling from existing underground workings will greatly reduce, if not replace, surface exploration drilling. Diminishing ore reserves along with increasing difficulty in acquiring access and permitting of drilling surface holes requires a change in procedure. The length and direction of the required long holes is site specific, but once determined could be quickly mobilized. Data would be available for a much more timely evaluation without any surface disturbance and required reclamation issues. Preplanned directional drilling from underground will also provide an evaluation of already inconsistent uranium deposits located under surface terrain that is inaccessible to surface drilling.

Aug 1, 2010

By C. Andrews

Fuel cell testing requires fully automated operation, on-site configuration of tests, and real-time monitoring for performance and failures. Balancing the flexibility and programmability of a test station with reliability, cost, and user interface can be a daunting challenge to the test equipment engineer. Endurance testing of fuel cells requires the highest level of reliability for test stand hardware and software without compromising automation capabilities or users interface. Techniques for implementing an ultra-reliable test platform addressing hardware limitations, sophisticated watchdog monitoring to prevent inadvertent shutdowns, and software limitations (e.g., balancing a highly-functional graphical users interface with reliability) are presented.

Jan 1, 2005

By J. H. Parliament

"The 15,000-tpd Similkameen open-pit copper mine, 10 miles south of Princeton, B.C., started production during 1972. The two main ore zones are separated by the deep canyon of the Similkameen River, with the Ingerbelle or western deposit being mined first. The location, design and construction of the plant were complicated by the steep terrain and the situation of the orebodies. Mining, utilizing 10-cu.yd electric shovels and 100-ton electric-wheel trucks, is conventional. Closely integrated with the preproduction mining was the construction of a 4-mile section of main highway to bypass the Ingerbelle pit. This entailed a very large fill, placed with mine equipment. Ore is crushed to minus 9 inches, stockpiled and reclaimed for direct delivery to three 32-ft-diameter by 14• ft single-stage autogenous grinding mills, each driven by two 4000-hp motors. Because of the friable ore in the upper part of the mine, 4-inch balls are added, with higher than design throughput attained. Classification is by 91>-inch spiral classifiers and cyclones. The flotation section comprises three parallel lines of ten 400-cu.ft rougher- scavenger cells and a single line of 100-cu.ft cleaner and recleaner cells. Concentrate is transported in end dump, closed trucks to Vancouver for dockside storage prior to shipment to the smelter. Tailings are piped across the canyon on a suspension bridge and through a tunnel to an empoundment area. Water is reclaimed and returned to the concentrator, forming a closed system. Dams are raised with cycloned ands, with the downstream section compacted."

Jan 1, 1973

By S. Amira

The corrosion behavior of high pressure die-cast and thixocast AXJ530 magnesium alloys has been investigated in 0.05M NaC1 solution at pH 6.0 using potentiodynamic polarization tests, electrochemical noise (EN) technique, electro-chemical impedance spectroscopy (EIS) and scanning reference electrode technique (SRET). The behavior of die-cast and thixocast specimens were compared using each of these techniques and the results discussed. Further tests have been carried out with die-cast AZ91D alloy to better compare and interpret the results. Experiments indicate that the thixocast specimens of AXJ530 alloy have a better corrosion resistance than those of die cast alloy in neutral solution.

Jan 1, 2006

By J. W. Reynolds

Use of crushed waste rock recovered by sink-float separation from normal ore production for backfill is an established procedure at Commco's Sulhvan mme, Kimberley, British Columbia. Need for a safe method of placement in voids which were difficult to reach by gravity methods led to a co-operative venture with Radmark Engineering Ltd. in the development of a workable pneumatic transportation system for rock material. This paper reviews work done to date in a current program, and includes comments on the nature of the fill so placed, options for cementing such fill, implications for other aspects of mining and references to other applications of the system by other organizations who exchanged experiences with the Sullivan mine staff during the five-year period reviewed.

Jan 1, 1972

By T. G. Phillips

"This paper gives an inside look at a bulk terminal and describes the preparations that must be made by a company in developing such a terminal and its position in today's traffic pattern. The following headings cover the subject material: (a) Traffic pressures, their detection and measurement, (b) position in the traffic flow -selection of site, (c) transportation connections -present and possible future routes, (d) engineering studies and costs, (e) contracts, the basic material for insured traffic, (f) financing, (g) budgetary control, (h) development of new techniques, (i) growth into new cargoes or cargo-handling methods and (j) consolidation."

Jan 1, 1968

By J. Schick, V. Granger

Nowadays, all French former uranium mining sites are remediated and redeveloped. If needed, mining waters containing radium have to be treated before discharged into the environment. Classical radium treatment consists in a (Ba,Ra)SO4 salt precipitation and radium monitoring was carried out using a time-consuming analysis called emanometry. Three zeolite samples have been tested to remove 226Ra from mining water. In batch experiment, radium was totally (R=100%) and quickly removed after 2 minutes contact time. Continuous sorption experiments were carried out through a vertical column at lab scale. Chabazite is the most efficient zeolite with an 226Ra activity below 0.2 Bq/L until 60000 Bed Volume. Chabazite is always efficient although radium content in material reaches 150 Bq/g. 226Ra uptake was also tested at semi-industrial scale on a pilot plant. More than 3000 m3 were successfully treated with a radium content below 0.1 Bq/L. The environmental impact assessment of Ra-chabazite was characterized by using batch leaching tests made according to the NF EN 12457-2 standard as applied on all wastes. Ra-chabazite stability is excellent during this test: radium leaching is very low, less than 0.005%. A new 226Ra measurement method was developed by ICP-MS for a better analysis reactivity. This new method was carried out in a couple of minutes with a lower sample volume than emanometry. The validation was performed according to the French NF T90-210 standard for the calibration function definition, the limit of quantification, the accuracy and the interferences.

Jan 1, 2020

By N. R. Thote, J. L. Porathur, C. P. Verma

Highwall mining is a highly mechanized coal mining method associated with several advantages, such as a very high production rate (approximately 3,000 t/d) and low production costs. There is no requirement for underground support, ventilation, or blasting. Production leads to added recovery, which is otherwise lost in the ultimate pit. The use of highwall mining can bridge the gap that exists between supply and demand in the energy sector. This paper presents a brief review of highwall mining technology, including current status, analysis tools, and design techniques. In addition, it identifies important parameters from the analysis of failure case studies.

Jan 1, 2014

By Ali Montaser

Hauling trucks are important part of equipment fleets for large earthmoving operations such as those encountered in dams and highway construction projects. This paper presents an automated methodology for tracking and estimating productivity of hauling trucks fleet operations in near-real-time. Recent advancement in automated site data acquisition technologies made their use in tracking and monitoring of construction operations feasible. However, these technologies fail to track hauling truck fleets due to the change in the cut and fill locations from one cycle to another; making tracking and progress reporting difficult and inaccurate. In addition, there is very little work done utilizing data sensed directly from equipment, for example sensing when truck dumping bed is raised during the dumping process. The technologies deployed in the developed method are Radio Frequency Identification (RFID) and equipment control sensors. Low cost passive RFID tags are attached to hauling trucks and fixed RFID readers are attached to loaders or excavators. The read range of the used RFID tag is centimeters, to be activated only when a loader with an attached RFID reader is loading a truck. On the other hand, control sensor is connected to the truck control system and operated by the motion of its movable bed. The function of control sensors is to record the signal time when the truck operator gives order to the truck control system to raise or lower truck bed. The captured data is then transferred wirelessly from the RFID reader and control sensor to a computer housed in one of the temporary offices onsite and subsequently to the main server in the contractor?s head office. Fusing the data captured from RFID reader and control sensor is used to identify loading, travel, dumping and return time that constitute the hauling truck cycle time. The collected data is analyzed and processed automatically, without human intervention, to calculate the productivity of the hauling truck and to report it directly to onsite personnel. Relational database is developed to support the implementation of the proposed method. The developed database is used to process the data captured by the RFID and the control sensor to calculate the productivity achieved in cutfill operations in near-real-time. The developed methodology is expected to facilitate early detection of discrepancies between actual and planned performances.

Aug 1, 2013

By Renato Macciotta

The argillaceous formation known as the Opalinus Clay is host to the Mont Terri Underground Research Laboratory. The URL was developed to investigate the hydrogeological, geochemical and geotechnical properties of the formation. Underground excavations at the site are characterized by non-elastic and time-dependent deformations. Excavations trending perpendicular to the strike of the bedding presented relatively minor deformations, however, tunnels parallel to the strike of the bedding showed much larger non-elastic deformations. This paper presents an analysis of the measured response of a tunnel trending parallel to the strike of the bedding in Opalinus Clay. The measured convergence is compared to tunnel experience in weak rocks to assess the tunnel stability.

Jun 1, 2012

By Frank Otten, Jochen Greinacher

"In July 2017, Deilmann-Haniel signed a contract with IOO Slavkaliy to sink two 750 metre (m) deep freeze shafts for the Nezhinsky Potash mine in Belarus. This is the second shaft project where this technology is employed after two over 1,000 m deep shafts for a potash project in Saskatchewan, Canada, have been sunk by the application of the Herrenknecht Shaft Boring Roadheader (SBR) technology. Developed to sink shafts for green field projects in soft to medium hard rock, in frozen or unfrozen geology, the machine technology utilizes a roadheader-type cutterhead on a telescopic boom to mechanically excavate the rock, and a pneumatic mucking system to convey the muck from the face into the buckets. This leads to a manless face during the sinking cycle and thus a significant improvement in terms of workplace safety. For the Nezhinsky project, the SBR design was significantly modified in close cooperation between Deilmann-Haniel and Herrenknecht, based on the available experience and the special requirements of the project. Such modifications have been for example the adaptation of the Pneumatic Mucking System to cope with wet material as well as dry as originally planned or the shaft lining moving from shotcrete application to jump for and tubbing installation for which a step-change hands-off tubbing erector for the placement of segments was designed. Further modifications to optimize the machine technology for the requirements during shaft sinking were applied on the two machines for the Slavkaliy project as well as several revisions to match the special project requirements. The SBR is suitable for soft and medium hard rock up to 100 MPa UCS. The main design limits are maximum weight of the machine with 400 tonnes and length or height of 50 m due to the depth of the pre-sink. The Pneumatic Mucking System was changed in all components, sheaves and rope arrangement were redesigned and the concept of the hoist system was also re-engineered. The SBR in Belarus is configured for a daily sinking rate of three metres and all systems behind the cutting boom are not the bottle neck of the whole system. The works on site started in November 2017 including freeze hole drilling, construction works, site setup, installation of hoists winches, permanent headgears and other components required for sinking. The SBRs arrived on site in June/July 2018 and were preassembled on surface and then lowered into the 50 m pre-sink. SBR #1 started full face sinking in mid-December 2018, and SBR #2 in late January 2019. By the end of February 2019, the machines were at 150 m and 100 m depth respectively, and achieved up to 3.6 m/day concrete lined shaft. The SBR and the sinking system, the experiences, problems, technical solutions and performances of this challenging project will be presented in this paper."

Jan 1, 2019

"Real time analysis of conveyed bulk materials can be used to improve process performance by reducing variability and upgrading ore quality through selective removal of increments of flow that do not meet appropriate selection criteria. This paper focusses on proven Prompt Gamma Neutron Activation Analysis (PGNAA) and microwave transmission technologies used to representatively measure conveyed ore quality in real time so that meaningful decisions can be made between the mine and mill. This enables the effective removal by bulk diversion of small increments of conveyed flow such as waste, highly deleterious material or sub-economic material from the mill feed. Improved ore quality in plant feed optimises process performance, reduces processing costs and minimises tailings generation. Analysis is unaffected by particle size, dust, layering or segregation, mineralogy and belt speed. Technologies are explained and performance examples given from installations in copper and iron ore. The technology has been used successfully in bulk sorting for over twenty years typically using measured increments of a few minutes. Improvements in technology and calibration performance have resulted in accurate measurements over increments of thirty seconds and below.INTRODUCTION Ore quality variability exists on a number of scales. Block model grades represent a few hundred to many thousands of tonnes. Grade control at the mine occurs on a scale typically down to the size of a haul truck, which may be a few hundred tonnes. Highly variable ore quality is detrimental to process efficiency and effectiveness. Processing waste or low grade ore when higher quality feed is available represents a lost opportunity to generate higher revenues earlier in the operational life. Measuring ore quality accurately over short time increments during conveying enables small increments to be measured and diverted according to their quality. The paper explains the technology and benefits. Neutron irradiation techniques were considered potentially suitable for conveyed bauxite measurement by Beurton et al, 1995. Tran & Evans (2001) concluded there was no equivalent technology to Prompt Gamma Neutron Activation Analysis (PGNAA) in terms of material penetration power. PGNAA was evaluated by Nelson & Riddle (2003) for possible use in the phosphate industry and recommended its use for further characterisation of the mine’s various ore types to improve stockpile allocation and grade control. Cottle (2007) discussed test work for an iron sinter application and Delwig et al (2011) described the successful installation in 2009 and performance of PGNAA for base-to-acid ratio control in sinter feed with the analyser output used to control lime addition. Geoscan (PGNAA) works very well on iron ore and can “improve control over what is happening in the plant” and that comfort can be provided in knowing that the product is on-spec according to Minnett (2010). PGNAA is not yet used in the minerals sector for tariff purposes as has occurred since 2000 with Coalscan (PGNAA) in coal (Minnett, 2010)."

Jan 1, 2017

By J. Manchisi

This study has investigated the use of blast furnace slag as functional adsorbent for metal ions in acid mine drainage treatment. This opportunity has not yet been developed into a practical process partly because of limited understanding of rates and mechanisms of adsorption process and inconsistency in interpretations of adsorption data. The overall objectives were to determine the efficiency and mechanisms of sorption process of metal ions in a multiadsorbate system. We employed standard materials characterisation techniques to analyse composition, structure and surface morphology of the slag. Batch adsorption experiments were then conducted to study the mechanisms, kinetics and efficiency of metal sorption as a function of pH, phase ratio, mixing time, mass and particle sizes of slag. Both XRF and adsorption data suggested the slag to possess acid neutralising capacity. This slag is non-crystalline based on XRD pattern, has adequate porosity and pore volume comparable to similar commercial adsorbents but it has inferior pore structure, pore size distribution and BET surface area to be effective under wide applications. Metal sorption increased with decrease in slag particle diameter, decrease in initial metal concentration and increase in the mass of slag. Although slags have demonstrated to efficiently treat low concentrations of single and multiadsorbate effluents using fine particle sizes, they have limited capacity to treat multiadsorbate systems for some metal ions. This is probably due to low affinity, competitive adsorption or limitation in material?s adsorptive properties. Sorption mechanisms probably involve precipitation and ion exchange on the basis of alkaline pH and exchangeable slag surface ions. Sorption preference is proposed as Fe2+>Cu2+>>Cd2+>Co2+>Mn2+. Despite these limitations, deeper understanding of sorption behaviour of metal ions by slags for application in dilute and large volumes of effluents is necessary where precipitation and other standard techniques are either inefficient or uneconomic. Thus, this study has established that sorption capacity of slag to remove metal ions from acidic effluents is selective, limited to certain metal ions and for other ions only at low concentrations. Further adsorption studies in multiple solutes under various experimental conditions or those that can propose an economic slag activation process are needed that improves or widens adsorption window.

Aug 1, 2013

By P. Lind, A. Gagnon

"Goldcorp has embarked upon an ambitious, industry-leading, multi-year water use reduction effort. This is a proactive, voluntary effort that reflects our commitment to truly sustainable mining. This effort will focus on increasing water re-use and recycling, and reducing water inputs ultimately towards zero. All of our operating mines are expected to contribute to this effort and are currently in the process of developing plans to meet short and long term objectives. One of the largest needle movers to increase water re-use and recycling is in the area of tailings management. Within five to ten years at Goldcorp, it is envisioned that the need for wet tailings dams will be eliminated and that all new tailings facilities will consist of only filtered or dewatered tailings. Filtered tailings is developing into a mature technology with wide application in mine waste management. This paper describes a conceptual level evaluation on the transition from a slurry to a filtered tailings operation at the Cerro Negro mine in southern Argentina. Key benefits and challenges are highlighted.INTRODUCTION Goldcorp’s Cerro Negro operation is located in the Santa Cruz province in the Patagonian region of Argentina. Cerro Negro has been in operation since 2014 and commercial production was achieved on January 1, 2015. The processing capacity of the plant is 4,000 tonnes of ore per day and in 2016 produced 363,000 ounces of gold and 3.1 million ounces of silver (Goldcorp Inc., 2017). As the mine is located in a semi-arid area, it is important to evaluate technologies that could reduce freshwater consumption and maximize water re-use and recycle rates. The current tailings operation at Cerro Negro incorporates pumping of tailings slurry into a conventionally lined Tailings Storage Facility (TSF). Water is reclaimed from the tailings supernatant pond to the process plant via pumps, however, water losses occur due to evaporation and solution retention within the slurry tailings voids. Converting to a filtered or dewatered tailings operation would allow for increased water recovery prior to tailings disposal, and decreased water losses from evaporation and from retention in the tailings solids void space. This paper describes a conceptual level evaluation on the transition to filtered or dewatered tailings with the primary objective of moving closer Towards Zero Water."

Jan 1, 2017

By Rick Coleman, Chelvan (Chevy) Veloo

"P.T. Freeport Indonesia's lrian Jaya Operation has been producing copper concentrate continuously since 1972. Numerous ore discoveries and five mill expansion programs have seen the initial milling rate of 7,200 MTPD escalate to the present rate of 125,000 MTPD, producing 2.5 million pounds of copper and 3,500 troy ounces of gold per day. The latest expansion, commissioned in February 1995, incorporates a 34 foot Semi- Autogenous Grinding (SAG) Mill, two 20'x30' Ball Mills, conventional roughing, cleaner column flotation, and attendant upgrades to the existing concentrate pumping and dewatering facilities. This paper will describe the SAG Plant flowsheet, and focus on the key training issues which contributed to a successful plant start-up.IntroductionP.T. Freeport Indonesia's operations in the Ertsberg mining district are located in the Jayawijaya Mountains of Irian Jaya, the easternmost province of the Republic of Indonesia. P.T. Freeport Indonesia (PTFI), the operator, is owned by Freeport MacMoRan Copper and Gold (81.3%), the Government of Indonesia (9.4%), and private Indonesian investors (9.4%). Geographical location, and sailing distances are provided on the attached location map.The operation stretches over 7 4 miles ( 114 km) from the dewatering and concentrate shipping facility at the Port of Amamapare on the Arafura Sea to the Grasberg open pit located at 3400m. The regional geology is covered in detail by Van Nort et al (1991 ), with current proven and probable reserves estimated at 1.13 billion metric tonnes grading 1.30% Copper, 1.42 ppm Gold, and 4.06 ppm Silver. The Grasberg open pit mining operation provides 92% of the mill feed, and is described in detail by Hickson (1991). The remainder of the mill feed is derived from several underground block caving operations. Current production rates provide a mine life in excess of 25 years. However, very favorable geology in the area leads to expectations that additional reserves will extend the life of the operation considerably."

Jan 1, 1996