Search Documents

By B. Petri, N. Rouse

"Air overpressure monitoring procedures and instrumentation guidelines which apply to production blasting in underground limestone mining are not readily available. The industry also lacks an applicable source for air overpressure levels that are produced by blasting operations in underground limestone mines. As such, there was no available background data from which the expected overpressure levels from production blasting in a new underground limestone mine could be predicted. During the development phase of the mine, it was imperative that newly constructed underground structures be capable of withstanding the overpressure produced by blasting in nearby production headings. To ensure the structures could withstand the blast-induced overpressure, a study was conducted to record empirical overpressure data and develop a model which could be used to control air overpressure levels by the production crews. This document describes the procedures used to develop the model, the development of the model, and the applicability of the model for predicting underground blast overpressures. INTRODUCTION A developing underground limestone mining operation required that a ventilation wall be built to house the permanent mine fans. At the time of the study, the mine was a single-level room and pillar operation with a 7.9 meter (26 ft) high roof, 13.7 meter (45 ft) wide entries, and 13.7 meter by 13.7 meter (45 ft by 45 ft) pillar dimensions. The mine is accessed via a 396 meter (1300 ft) long decline and 100 meter (330 ft) deep ventilation shaft. The ventilation wall was to be partially constructed of autoclaved aerated concrete blocks, for which dynamic strength data from explosives loading were unavailable. The company ownership feared that airblast may affect the wall due to the close proximity of the working faces. Therefore, the company management asked that the overpressure levels be estimated and compared with the designed wall strength. Few studies that apply to explosively-driven air overpressure levels in underground production blasting were found through a literature review. Therefore, the logical approach to assess the overpressure levels was to monitor the blast pressures at the site and conduct a thorough evaluation of the data. As a result of this study, the equipment setup and monitoring procedure used to record the airblast data is described. Finally, the experimental data gathered during the monitoring program is presented, trends and findings from the data are discussed, and recommendations for further study are presented."

Jan 1, 2015

By V. C. Koppe, J. F. C. L. Costa, D. M. Marques, A. Amaral

Errors associated with estimating the grade of an attribute of interest in a deposit can compromise planning, sequencing, and mineral beneficiation decisions. Several factors are associated with estimation errors. Among them, we can highlight the factors associated with sample spacing, the size of production volumes, and the variability of the attribute considered in the estimation. The access to estimation error can be obtained by some geostatistical methods, for example, by stochastic simulation. However, this is a process that in some situations is computer intensive and takes time. Previous works have proposed a simplified method to access the Maximum Estimation Error (MEE) associated with different types of grade variables, depending on the sample spacing, at small production volumes and considering specific coefficients of variation ranges. This paper presents an approach to assess the MEE associated with long-term volumes. Considering the methodology proposed, it is possible to approximate if a specific drilling pattern used in a deposit provides an acceptable pre-determined estimation error for Resource Classification. Results and considerations on the impact of the geometry of larger production volumes on the MEE calculation are also presented.

Jun 25, 2023

By S. Chai

Waste dumps are widely used to discharge stripped mine wastes in open pit mining methods. As mining progresses, the height of the waste dumps will increase gradually, which may induce sliding failure once the height exceeds a critical value. Therefore, estimation of the maximum dumping height is crucial to the life-cycle use of a waste dump. However, published information about the maximum height of mine waste dumps are extremely rare. In this study, the maximum dumping height is estimated based on the strength-reduction technique by numerical simulations. The influences of dump geometry and properties on the maximum height are investigated. The results show that the maximum dump height decreases as the dump slope inclination angle α or the unit weight of dump materials γ increases, but decreases when the shear parameters of dump materials (cohesion c and internal friction angle ϕ) increase. The maximum height starts to increase with the ground inclination β when shear failure occurs at the interface between the dump and the base. Furthermore the effects of the dump width B, Young’s modulus E, and Poisson’s ratio μ of dump materials on the maximum height are almost insignificant. Good agreement was found between numerical results available in the literature and those obtained in this study.

Oct 1, 2022

By Adranyl W. W

Sub-level caving with bottom ore drawing has gained wide acceptance in rich, soft, low magnetic iron ores because it provides moderate ore dilution and ore losses. The main problem here is the high rock pressure exerted on sub-level drives situated in the sub-level sill pillars. To reduce this effect, the ore block is divided into panels. This paper illustraes the method of determining the maximum panel width providing low maintenance cost of sub-level drives.

Jan 1, 1995

By Donald Carlisle

"IntroductionTHE OPINION is held by many persons outside the mining industry, and by some within it, that mine •operators customarily find it advantageous to mine •only the richer parts of orebodies and to leave behind, perhaps permanently, leaner material which could be mined only at a lesser profit. This opinion and the inference which might be drawn from it that 'gutting' of mineral resources is a common feruture• of the mining industry are prejudicial to the intertsts of the industry and deserve careful scrutiny. Oddly enough, a theory of mine economics which gives much support for the opinion was advanced first by members of the mining profession itself, has been repeated •several times in mining literature, and to my knowledge has never been adequately refoted.According to the theory, selective mining of the rich ore first on a large scale will yield substantial gains and these gains do not merely reflect the desire of 'money minded investors' for a quick return but derive from the logical application of compound interest rates and the concept of ;present value. W. O. Hotchkiss and R. D. Parks (1) illustrate the reasoning with a hypothetical example in which an orebody of 4,000,000 tons may be mined either in its entirety in forty years at $1.00 per ton profit or selectively with the recovery of only the richest half in twenty years at $1.50 per ton profit. They show that, with Hoskold rates of 4 and 8 per cent, the present value of profits from mining only the richer 2,000,000 tons exceeds the present value of profits :from mining the whole orebody by about 20 per cent."

Jan 1, 1953

By Paul H. Rylund

Substantial priming was a considered necessity for proper initiation of ammonium nitrate-fuel oil mixes as ANFO began to carve its niche in the mining industry in the latter fifties. Heavy priming accompanied the introduction of prills and oil to many blasting operations, large charges of high explosives were commonly used at the bottom, top and frequent intervals through-out the column. As the quality of ammonium nitrate improved and operators became more experienced, primer costs began to diminish. Increased experimentation continued with reduced primer costs a main objective. Cast primers were introduced and became accepted as an excellent companion for ANFO. Although the trend toward larger diameter boreholes became increasingly popular, emphasis on lower and lower priming costs continued. A primer was simply required to produce any type of initiation within the ANFO column to be considered adequate. Suddenly ANFO priming had digressed from excessive to marginal. Early experimental data developed at "test site" and laboratory locations indicated that ANFO had a tendency to react inefficiently in the initiation region of the column unless substantially primed. This was evidenced by the presence of unstable reaction rates detected with newly developed detonation velocity measuring equipment. These 10" order or "transient" velocities were believed to originate because of inadequate primer strength or a primer diameter to column diameter mismatch. How-

Jan 1, 1972

R. F. MCELVENNY.- Over 20 years ago I went back East on a little tour of copper companies to see how copper was handled and fabricated, and I met a Mr. Bassett who took me through the Waterbury branche of the American Brass Co. I have not seen this gentleman for 20 years, but I have a letter from him that I would like to read to you. 'The American Brass Co. Waterbury, Conn. May 19, 1930. To the-Salt Lake City Conference on Reverberatory Smelting Practice: Through the courtesy of Mr. Scott Turner, Director of the U. S. Bureau of Mines, Mr. G. L. Oldright has been temporarily released from his regular duties to act as your secretary. We have asked him and Mr. McElvenny to make the necessary preliminary arrangements and to present to you at the opening session the greetings of the officers and' directors of the Institute. I am very glad that it has been possible for you to come together under the auspices of the Institute and that the acceptance of our invitation has been so very unanimous. Such an acceptance of the invitation to this meeting indicates your interest in getting together for an exchange of technical data and ideas. We anticipate that this meeting will be of real service to the smelting industry through your open discussion and exchange of ideas, and we sincerely hope that you will form an organization which will arrange for future meetings of a similar nature. While it probably may not be desirable to. distribute the minutes of this conference except to the members who take part in it, we hope that later the Institute publications may be enriched by such matter as you think it desirable to have published; and also, that some of you may be able to offer technical papers for the Institute publications. I hope that you will find a permanent organization desirable and trust that it will be possible for you to form such an organization so that conferences may be regularly called. We hope that you can make use of the Institute organization and that we can be of real service to your industry. With best wishes for your success in this undertaking, I am Most cordially yours, W. H. Bassett, President.

Jan 1, 1930

R. F. McELVENNY.- The next item is: "Center and other methods, vs. side charging." That was all discussed in the Carson case, and I do not know but what many of the plants are still using center charging. Some are using side charging. Did I understand that where you use the wet charge it is all side charging on the wet ore? B.-G. C. HONEYMAN.- We were on center charging for about a year with wet ore. R. F. McELVENNY.- Then you went to side charging. Has anyone any remarks to make on side versus center charging? E. A. BARNARD.- We have one side and one center, both on deep bath. It is an experimental proposition so far, but the side charge looks very favorable.. R. F. McELVENNY.- This is with calcine? E. A. BARNARD.- This is with calcine on a floating charge proposition.. They are both water jacket. The charge acts very similar on both center and side charging. The calcine spreads much the same as it does on the center charge. It will run down 75 ft. on the furnace side as well as the center. The advantage is in taking care of secondaries and things of that nature. C. BARDWELL.- Do you get any side wall protection from it? E. A. BARNARD.- No. R. F. McKENZIE.- Do you not project the side wall up to protect the skewback? E. A. BARNARD.- There is a slot projection down around the top of the bath; but the repairs on the side wall have been practically the same; that is, they, have been practically the same as they have on the center charge. A. H. RICHARDS.- A point I would like to make is that if you have any doubt about the center charging, we feel that we get better tonnages and lower fuel ratios and better slags with center charging than we ever got with side. Different kinds of charges would, of course, vary, and I could readily see that if you had the same advantage with deep bath smelting that you mention you would probably get just as good a slag and as good fuel ratios. E. A. BARNARD.- In fact, I think the calcine charge spreads more on the side than on the center charge. A. H. RICHARDS.- If you maintain a deep bath. E. A. BARNARD.- That is one thing we have to be careful about, to hold the charge back.

Jan 1, 1930

R. F. McELVENNY.- Mr. Oldright has just given me a letter to read to you, which I think it may be of interest. It is headed, "Silver Meeting Dinner". The letter is as follows: "To Members of the A. I. M. & M E.: The annual business meeting and election of officers will take place at the University Club, Wednesday, May 28th, 1930 at 7 p.m., at the Silver Meeting Dinner. The Nominating. Committee for next year's officers have proposed the following names: Chairman, Robert Wallace; Vice-Chairman, G. W. Crane; secretary, C. T. Van Winkle, Other nominations can be made at the meeting. Utah being the leading silver producer of the United States, constructive suggestions regarding the silver situation will be made at this meeting which are new and of general interest to the members. The speak¬ers will be followed by a Round Table discussion of the silver situation and proposed remedies. Speakers will be - W. M. Ferry, President of the Silver Producers' Association, 'Recent developments in the Silver Question'.. Senator Frank J. Cannon, 'The Cannon Plan'. George W. Snyder, 'The Manufacture of Sterling Silver.' Discussion by J. J. Beason, G. W. Crane, J. 0. Elton, J. W. Wade and others. Members of the Conference on Copper Reverberatory Smelting are invited to be present. Chairman J. A. Norden will preside. C. T. Van Winkle, Secretary. Dinner will be $1.50 per plate." The next subject is "Boilers: Proper construction of, so as to secure best utilization of heat from gases, and facility in removing dust and clinker with minimum losses in operation." Who is particularly interested in that subject? The type of boilers is practically a standard practice now. I do not know of anybody that is using the tandem system now. No one is building a plant with a tandem system in it.

Jan 1, 1930

By JAMES A. VEASEY

SINCE the World War, excepting for a few brief periods of relief, the American petroleum industry has been obliged to meet its important economic responsibility to this nation hampered by the maladjustment that inevitably follows a marked and unwholesome over-production of its raw material, crude oil. Despite the warnings of the Federal Oil Conservation Board and the endeavors of many of the leaders in the business to stem the flow of oil from the wells of the country, the evil ,not only persists but, at the moment, seems more malignant than ever before. Unless the local and temporary restraints on drilling and production now in effect in California, Wyoming, Texas, and Oklahoma are continued, and, indeed, unless stricter and more comprehensive measures of the same sort are imposed and adhered to by the industry in those States, over-production in the enterprise during the current year will be more pronounced than in any other period in history.

Jan 1, 1929

By H. S. Bostock

"The study of the geology of Mayo district began in 1900 with R. G. McConnell's exploration of Stewart river; and has been carried on intermittently for the Geological Survey of Canada by J. Keele; D. D. Cairnes; W. E. Cockfield; C. H. Stockwell; and the writer. It has revealed a thick group of schists; quartzites; and crystalline limestones; almost certainly Precambrian in age; placed in the Yukon group; and a group of younger intrusive igneous rocks varying in composition from granite to gabbro. These include bodies of many sizes and forms; from stocks 8 miles across to small dykes and sills.Prospecting in the district began about 1897 and has disclosed the presence of gold, silver, lead, tungsten, tin, zinc, antimony, copper, arsenic, manganese, and mercury, both in placer and lode deposits . Of these metals gold, silver, and tungsten have been produced from placer deposits, and silver, lead, and gold from lodes. This paper deals only with some structural relationships of the lode deposits, generally referred to as the silver-lead veins, which have yielded the greater part of the mineral production of the area. From 1938 to 1941 the geological mapping of the district for publication on a scale of 4 miles to 1 inch was carried out by the writer, and the ideas expressed here are based on this work. No comprehensive detailed study of the silver-lead veins has been made, but the mapping has brought to light several important facts. The rocks of the Yukon group, although of a striking sameness throughout their section, can be divided into a number of distinguishable members by means of which the main structures can be traced . The most important and readily distinguishable rock in the group is referred to here as the quartzite member. This is composed of quartzite and schist in about equal proportions. The quartzite is resistant to erosion and forms most of the outcrops of the'member and the peaks of the Gustavus mountains and mount Haldane (Lookout)."

Jan 1, 1954

By Keith P. Bingham

A total transportation system providing for delivery of finished products to customers and raw materials to the plant is one of the key elements contributing to Dravo Lime Co.'s success. Dravo Lime operates one of the largest noncaptive lime and limestone plants in the US at Maysville, KY, where products produced can cost as much to deliver as they do to manufacture, depending on the product itself, its destination, and mode of transportation. With delivery costs comprising a significant portion of total costs for its products, Dravo Lime has made total transportation services an integral part of its business strategy. Prices for most products produced at Maysville are quoted f.o.b. destination. In short, Dravo Lime's Distribution Department relies on the approach that says to customers: "Leave the delivery to us." The 0.9-Mt/a (1-million stpy) Maysville facility, located about 121 km (75 miles) east of Cincinnati, OH, on the Ohio River, primarily produces sulfur-absorbing Thiosorbic lime used by coal-fired electric utilities as a scrubber reagent to remove SO2 from stack gases. The product is currently supplied to eight power plants in the Ohio River valley region which extends through portions of Kentucky, Indiana, Ohio, West Virginia, and Pennsylvania. The plant ships approximately 907 kt (1 million st) of lime and a comparable amount of limestone fines each year. In addition, it arranges for delivery of about 181 kt (200,000 st) of coal to the plant. Lime is transported by covered hopper barges, covered rail cars, covered dump trucks, and pneumatic trucks. It is transferred from barges to storage silos and trucks at a terminal on the Ohio River near Marietta, OH. At another terminal near Aliquippa, PA, lime is transferred from barges to silos, trucks, and rail cars. Future plans call for rail-truck transfer terminals. To produce lime from limestone at the Maysville plant, about 181 kt (200,000 st) of coal is burned annually in three coal-fired kilns. In transporting this coal from the mine to Maysville, Dravo takes maximum advantage of opportunities for reloading carriers with limestone for outbound backhaul movement. Coal, shipped from southeastern Kentucky mines in rail cars, is transferred to barges at a river terminal in West Virginia. After it is unloaded at Maysville, the barges are cleaned with a front-end loader and then reloaded with limestone. Limestone also is backhauled in connection with truck deliveries of coal. The economics of using backhaul shipments has permitted Dravo to enter into markets in which Maysville limestone otherwise would not be competitive. The company plans to backhaul limestone in empty open hopper cars in the future. As part of its ongoing assessment of the distribution system that supports the Maysville operation, Dravo Lime recognizes that a new environment has developed between shippers and carriers because of regulatory changes in the railroad and trucking industries. Although dry bulk shipments by barge to and from Maysville have always been unregulated, other forms of transportation have not. With railroads and motor carriers now approaching varying degrees of deregulation, contracts and agreements are replacing tariffs, and rate negotiations are becoming a daily activity. Dravo Lime plans to take advantage of these transportation changes, all of which may be beneficial to both its plant and its customers.

Jan 10, 1982

By Jorge Olivari Ortega

"Los incas desarrollaron un censo que les permitía planificar el desarrollo socio-económico de la región, como la actividad minera aurífera. En ese sentido, el gobierno del inca Mayta Cápac elaboró un sistema estadístico, a partir de los quipus para registrar toda la información y obtener el máximo provecho de los recursos existentes. Por ello, el presente texto describe el proceso del método estadítico que permitió a los incas adquiirir el tributo que habían programado. Para ello, se utilizaron los cordones de variados colores (quipus) para diferenciarlos en cada actividad como el amarillo que significaba la actividad minera aurífera. En estos cordones, los quipucamayoc registraban la cantidad de oro producido durante la mita minera o con los mitimaes en los yacimientos auríferos el número de personas que participó, la cantidad de días, las herramientas, los viveres, los vestidos, etc. Las herramientas utilizadas en la explotación de los yacimientos auríferos tipo lavadero, son las mismas que en la actividad agrícola, ya que en ambas se requieren remover la tierra: en la agricultura para sembrar las semillas, y en la minería aurífera, para lavarla y obtener las partículas de oro."

May 1, 2016

By Harry Sutcliffe, Francis M. Keville

The paper describes the, impact of the geotechnical exploration program on the line and grade of the tunnels and the shaft configuration on the Red Line Extension N.W. in Cambridge and Somerville, Massachusetts, and comments on several aspects of the implementation of the project.

Jan 1, 1983

By Gregory Yates

INTRODUCTION Project Description The Silver Line is a Bus Rapid Transit (BRT) Line and is Boston?s newest transit service. Silver Line Phase I extends along Washington Street entirely on the surface in priority bus lanes from Dudley Station in Roxbury through the South End and Chinatown neighborhoods to downtown Boston. The Phase I opened in July 2002. Silver Line Phase II consists of an underground transit tunnel from South Station to the South Boston Waterfront with underground stations at Courthouse and World Trade Center to Silver Line Way east of D Street. Phase II continues through the Ted Williams Tunnel to all the terminals at Logan Airport, and on the surface to the Boston Marine Industrial Park and City Point. Phase II opened in December 2004. Silver Line Phase III is a one mile tunnel connection to the existing Phase II tunnel in the vicinity of South Station and will eventually portal on Tremont Street just north of Marginal Road. After leaving the portal, the buses will use dedicated bus only lanes on the surface roadway network to connect to the Phase I service. Figure 1 shows the alignment of the Silver Line upon completion of the Phase III project.

By Kevin Beirne

Most people involved in the mining industry are familiar with student-industry co-op work-study programs. Many colleges and universities have used them for years. Northern College’s Haileybury School of Mines student co-op program adds a new dimension of productivity to the college and the mining industry. The college is located in Hailey-bury, Ontario, Canada. An example of the program’s success is the school’s relationship with Sabin Metal’s SMC (Canada) Ltd.’s McAlpine Mill in Cobalt, Ontario. Students gain practical knowledge and experience while industry gains an eager-to-learn worker. And many of the college’s advanced research services are made available to industry to supplement their own capabilities. The McAlpine Mill was established to provide custom milling of slags and ores. It also recovers metal values from other products of the primary and secondary precious metal industries.

Jan 1, 1999

By K Cameron, S Strohmayr, J Wallace

In 2012, a single module heavy medium cyclone plant (HMP) was installed at the Glencore Zinc’s (then Xstrata Zinc) McArthur River lead zinc mine. The HMP formed the first part of the MRM Phase 3 Project to increase run of mine (ROM) capacity from 2.4 to 5.5 Mt/a.The purpose of the HMP is to remove liberated gangue from the crusher product at minimal loss of valuable mineral. The McArthur ores are very finely disseminated requiring a fine primary grind size prior to rougher flotation. Rejecting waste prior to grinding therefore offers significant power and grinding media savings. The plant was designed to treat only those ores with a reasonable upgrade ratio at the target zinc recovery across the HMP of 95%.On this basis, a 1.8 Mt/a single module plant was built based on 250 t/h feed rate and 82% availability. In contrast to existing base metal heavy medium plants in Australia, the MRM Flow sheet utilised the principles in modern coal heavy medium cyclone plant design. Since commissioning, the plant feed rate has been significantly increased and is now normally operated up to 540 t/h (dry basis).Although this throughput increase is partially due to debottlenecking work, it is also attributable to the conservative design parameters for base metal heavy medium cyclone circuits in comparison to those used in equivalent coal circuits.This paper discusses Flow sheet design and compares traditional base metal design parameters with those achieved at MRM and those of modern coal plants. It provides information on plant capital and operating costs and the net savings realised by its installation. In addition to power and grinding cost savings, the paper also highlights the savings in water through rejection of near dry waste and reduction of tailings pumped to the storage dam.CITATION:Wallace, J, Strohmayr, S and Cameron, K, 2015. McArthur River Mine heavy medium plant – the benefits of applying modern coal plant design principles to base metal heavy medium separation, in Proceedings MetPlant 2015, pp 311–323 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

Thank you chairman, good afternoon ladies and gentlemen. In my talk this afternoon I intend to cover a brief history, some of the recent experiences and an overview of the McArthur River project.If we consider the themes of this forum, Obstacles and Opportunities, I can confidently say that in attempting to develop the McArthur River deposit Mount Isa Mines Limited (MIM) must have encountered almost every obstacle that can be imagined. However the large size and the high grade of the deposit has ensured an opportunity, from which it is very difficult to walk away from.The McArthur River Here's Your Chance (HYC) Deposit is located in the Northern Territory of Australia. It was discovered by Mount Isa Mines Limited geologists in 1955 and is one of the largest known sedimentary stratiform zinc-lead-silver deposits. The deposit has been the subject of numerous investigations and considerable expenditure culminating in a major feasibility study in 1979. There were a number of factors which prevented development, these being the size of the project, the fine grained mineralization, geographical location, market, social and capital cost. The latter had been estimated in the 1979 study to be $800 million at that time.

Jan 1, 1993

By J. Spross

"The Key Lake mill has operated since the fall of 1983. The ore from both Key Lake open pits will be depleted by 1997. It is planned to use this mill, located about 60 km southwest of McArthur, to process the McArthur River ore.While the geological data collected so far on the McArthur deposit are encouraging, more information of the deposit is needed before any detailed mine planning can begin.The surface drilling program identified the orebody and provided information on the geomechanical and hydrological properties of the overlying sandstone. It was proposed to conduct an underground exploration program to further delineate the orebody. This was air proved following a public hearing and review process. This program involves the sinking of a 630 metre deep shaft and the driving of one or two drifts along a portion of the orebody. From these drifts, exploration drilling every 10 m to 15 m through the orebody will provide the information required for the preparation of a feasibility study and an Environmental Impact Statement (EIS)."

Jan 1, 1994

By T. S. Grewal, S. C. Gupta, H. Natarajan, T. W. McQuade, N. Nejibulloev-Mamedov

Cigar Lake is one of the world’s largest high-grade uranium mines. The ore mined at Cigar Lake is milled at Orano Canada Inc’s (Orano) McClean Lake mill. The average Cigar Lake ore uranium grade since the start of mining activities in 2014 is 17.8% U (range 8– 28%). To achieve budgeted production of 18 M lbs U3O8/yr the required average feed tonnage to the mill is about 45 kt/yr. Arsenic, occurring as arsenides and sulpharsenides, is one of the major elements of concern associated with Cigar Lake ore. The leaching process is a sulphuric acid leach under oxidizing conditions at near atmospheric pressure. The presence of arsenic in the ore consumes oxidant in leaching as well as ferric sulphate in tailings preparation for arsenic sequestration. The average arsenic grade since the start of mining at Cigar Lake is 0.57% As. Further, the ore is hosted in a matrix of sandstone and clay, which results in poor settling in CCD. The average uranium grade for the balance of Cigar Lake Phase 1 ore is expected to drop to 12.5% U and the average arsenic grade is expected to increase to 1.6 % As, with an annual average peak of 2.5%. Therefore the tonnage throughput required to sustainably meet the production target will increase to 55 kt per year. Orano partnered with Hatch Ltd. (Hatch) to perform a gap analysis study to identify key circuits and equipment in the mill that would require debottlenecking. A METSIM mass balance model of the McClean Lake mill was generated and validated with actual mill operating data. Various feed scenarios were then studied, and the outcome was a traffic light table, which highlighted feed scenarios that exceeded installed capacity of major equipment and circuits. The results provided the basis for the PDC for the pre-feasibility study. This paper will outline the results of the gap analysis, the mass balance model, the feed scenarios and the study undertaken to prepare the McClean Lake mill for the change in ore quality from Cigar Lake.

Jan 1, 2020