BASE METAL MINES

Copper Cliff Tailings Area
SENES evaluated long-term disposal and closure alternatives for the Copper Cliff tailings in 1993, and updated the evaluation in 1996. The 1993 study evaluated seven primary options which included a base case (which was the plan in effect at that time), dam raising utilizing low sulphur tailings, construction of dams with an impervious core, changes to the physical area to be used for tailings disposal, the use of cut-off walls and clay caps, the use of a thickened tailings cone, and the application of an oxygen barrier cap. The 1996 update evaluated the 1993 closure plan based on how the tailings area had been developed over the three intervening years, the implications of new laboratory and field research, production testing of low sulphur tailings, and emerging acid mine drainage control technologies. (INCO Limited)

East Kemptville Tin Mine
SENES was the prime consultant for preparation of the mine's Closure Plan. In the absence of specific closure guidelines in Nova Scotia, the overall plan under development has been structured to meet Ontario mine closure guidelines. The closure plan must address acid generation concerns and the associated releases of contaminated runoff and seepage. The closure plan addresses all components of the mine including mill facilities, fuel storage, miscellaneous buildings, hazardous waste management, refuse, demolition debris, open pit mines, ancillary facilities, low grade ore, waste rock and tailings.

The plan evaluated reclamation options from end cost and environmental perspectives and has recommended a closure proposal which minimizes cost while meeting Rio Algom's environmental policies. (Rio Algom Limited)

Kam Kotia Mine Property
In 2000, SENES Consultants Limited was the successful bidder for the Phase 1 Kam Kotia Mine Site Rehabilitation Study undertaken on behalf of the Ontario Ministry of Northern Development and Mines. The Kam Kotia copper-zinc mine operated intermittently between the 1940s and 1967. Sulphidic tailings and waste rock disposed in many areas across the mine property generated acid drainage that adversely impacted the receiving environment. An expert team led by SENES was given the task to develop a rehabilitation plan that includes practical and cost-effective strategies to address the immediate environmental concerns at the site which relate to impacts to receiving waters and fish habitat; and allows for the progressive rehabilitation of the site by the Province. The Kam Kotia site includes three extensive tailings areas, waste rock piles, two mine plant sites, the former mill site, old power line, crown pillar, and areas impacted by acid drainage. (Ontario Ministry of Northern Development and Mines)

Kidd Creek Zinc Mine
A closure plan for Kidd Creek’s 1015 ha thickened tailings management area was prepared and submitted to the Ontario Ministry of Development and Mines in 1997, in accordance with Ontario regulations. The closure plan describes the history of the site and its current condition, and then presents the preferred rehabilitation plan for the site, which is designed to inhibit the production of acid drainage. The closure plan addresses the long-term physical and chemical stability of the tailings management area, and the requirements for long-term collection and treatment, care and maintenance, and monitoring. (Falconbridge Limited)

LAC Minerals Inactive Mine Sites
SENES provides ongoing advice regarding more than ten inactive mine sites owned by LAC Minerals. The services rendered include periodic site visits, evaluation of environmental data collected from ongoing monitoring program and investigation of specific concerns as they arise. (LAC Minerals Ltd.)

Levack/Onaping Area Nickel-Copper Mines
This project involved development of closure plans for ten underground nickel-copper mines located near Sudbury, Ontario. One closure plan was developed for all ten mines since the mines are located so closely together that the closure plans cannot be made in isolation. Closure strategies for the entire area were developed and evaluated, and the preferred closure methods were then documented in a report submitted to the Ontario Ministry of Northern Development and Mines, in accordance with Ontario regulations. Issues addressed included management of waste rock and tailings, long-term physical and chemical stability, and requirements for long-term treatment, care and maintenance, and monitoring. (Falconbridge Limited and INCO Limited)

Nanisivik Base Metal Mine
SENES provided advice and guidance to Nanisivik Mines regarding the closure of the lead/zinc mine located on the northern tip of Baffin Island. SENES' role has been to review data, recommend appropriate studies, provide expertise and written submissions for components of the closure plan and to support the company as necessary in public meetings. (Nanisivik Mines Limited)

Neves Corvo Base Metal Mine
SENES was a member of a team which developed the conceptual closure plan for the Somincor/Rio Tinto copper tin mine in Portugal. The closure plan has been recently completed although current reserves should extend operations for another 15 years. SENES' role was to evaluate the major environmental concerns such as acid mine drainage and hazard waste management, and develop operational practices to minimize closure costs. In this regard, several operational changes have been implemented at minimal cost and will save several million dollars at closure. (Somincor/Rio Tinto Corporation)

North Coldstream Copper Mine Tailings Management Areas, Ontario
SENES Consultants Limited had key roles in the development, implementation and post-closure monitoring of two tailing management areas at the historic North Coldstream Copper Mine located northwest of Thunder Bay, Ontario. The work conducted by SENES included: an extensive two year long field investigation program aimed at better understanding the characteristics of the tailings, hydrological and hydrological conditions, and assessing impacts to the receiving environment; development of the closure strategy; preparation of detailed ‘For Construction’ Engineering Drawings; audits of the closure construction activities to ensure that the works were carried out in compliance with the closure plan. TMA - 1 was decommissioned using an engineered dry cover with a capillary break layer. An extensive search was undertaken by SENES to identify and characterize suitable cover materials. The tailings containment dam was reprofiled and bolstered. TMA - 2 was decommissioned by dredging the tailings beach and relocating the material to deeper parts of the pond. (Alberta Energy Corporation)

Selbaie Base Metal Mine
SENES has provided advice and guidance to both BP Selco and Billiton Metals regarding closure plan options and costs for La Mine Selbaie operation. (Billiton Metals Canada Inc.)

Willroy Base Metal Mine
On this project, SENES assisted LAC Minerals in developing a closure plan for the Willroy lead/zinc mine. SENES' role was to assess current environmental effects, address remedial actions and provide input on environmental aspects of the closure plan. (LAC Minerals Ltd.)

Winston Lake Zinc Mine, Ontario
SENES participated in the development of decommissioning plans for Winston Lake mine in the early 1990’s and has continued to provide ongoing advice on environmental matters throughout the mine closure and reclamation process. SENES designed and supervised the operation of experimental columns which were used to demonstrate the effectiveness of water cover as a reclamation option for the tailings basin. A detailed assessment of the potential for AMD formation in the mine workings demonstrated that flooding the workings was advisable to prevent groundwater and surface water contamination problems. To accelerate recovery of water quality and aquatic biota in the Whitesand River immediately downstream of the tailings pond discharge, diversion of the effluent to flood the mine was recommended and implemented. Work on rehabilitation of a meromictic lake, which was affected by the tailings pond discharge, continues. (Inmet Mining Corporation)

COAL MINES

Coal Ash Usage, Germany
SENES prepared a literature review which examined research studies and field applications on the use of coal ash as an alkaline amendment for amelioration of acidic drainage from waste rock, and for treatment of acidic mine water. SENES subsequently performed geochemical modelling of the flooding of an historic mining region, to assess the effects of alkaline coal ash on mine water quality which had been used as sealant material in the underground drifts and as an alkaline backfill within caved zones throughout the mines. The assessment included evaluation of data on the geochemical characteristics of coal ash and the simulation of mine water quality in a vast area of mine workings affected by AMD. (Federal Ministry of the Environment, Germany)

Coal Mining, North America
SENES completed a comprehensive study in 1996 on the North American practices associated with coal mine waste management. The study included both state-of-the-art literature searches and direct correspondence with mining industry sources. (Confidential Client)

Coal Mining, Nova Scotia
SENES conducted a strategic management workshop for the Cape Breton Development Corporation, Nova Scotia - a coal mining company - titled "Strategic Planning Session for the Environment". The objective of the workshop was to help the top management of the company identify, prioritize and draw up an action plans for effective environmental management of the company's operations including potential closure liabilities. (Cape Breton Development Corporation)

Coal Mining, Poland
SENES has recently been retained by Industry Canada to develop an environmental joint industry/government workshop to be held in Poland to address the environmental issues related to coal mining operations, rehabilitation, decommissioning and closure. (Industrial Canada)

Coal Discard Dumps, South Africa
In association with Pulles Howard and DeLange (PHD), SENES completed a geochemical modelling assessment of decommissioning options for three large coal discard piles in South Africa. The modelling performed by SENES included: physical modelling of the transport of heat and air in the piles; geochemical modelling of the generation of acid and the production of contaminated seepage from the piles over the short-term and long-term, for several pile rehabilitation options; and, hydrological modelling of an ideal engineered soil cover that was proposed for remediation of the piles. (PHD)

Coal Refuse Piles, North America
SENES performed a geochemical modelling study of the effects of various treatment options (e.g. compaction, alkali addition, bactericide) on the generation of acidic drainage from coal refuse piles. This study included simulation of several small coal refuse test piles, as well as a large acid-generating pile, and comparison of the model predictions to monitoring data collected from the site.

Coalspur Project, Alberta
SENES provided expertise for the assessment of the environmental effects of developing an open pit coal mining operation in the Albertan foothills. Tasks undertaken included the development of estimates of air and water emissions to evaluate the potential atmospheric and aquatic impacts. (Dentherm Resources Limited)

Quintette Coal Mine, British Columbia
SENES was lead consultant on the preparation of a comprehensive environmental impact assessment for the largest coal mine in Canada - Quintette Coal. The assessment involved all aspects of the environment, including: air quality, water quality, land use, and biological studies. The environmental permit applications were completed under the direction of SENES and following extensive regulatory review, the necessary approvals were received. (Quintette Coal Limited)

PRECIOUS METAL MINES

Detour Lake Gold Mine - Canada
SENES undertook an overall assessment of the acid generation potential of tailings, waste rock, the open pit and low grade ore dumps at the Detour Lake mine in northeastern Ontario. The assessment included an evaluation of potential concerns and development of recommendations to mitigate future concerns. The report also reviewed potential closure options and costs. (Placer Dome Inc.)

Doyon Gold Mine - Canada
SENES has undertaken several assessments for LAC Minerals at La Mine Doyon. These studies include: modelling of the acid generation potential of sulphidic waste rock and tailings; a research investigation into cyanide degradation in the tailings pond; investigation of alternative water supply and water management; a research investigation into cover material alternatives for capping acid generating waste rock; a technical review of the mine water treatment system operation, including recommendations for upgrading the system and for sludge management; identification of long-term closure concerns; and, providing advice on appropriate management and mitigative measures to address decommissioning of the site. (LAC Minerals Ltd.)

ERG North Basin, Ontario
This project involved the development of closure options and recommendation of a plan of action for the remediation of the ERG North tailings basin. The study involved site reconnaissance; a downstream biological survey; sampling and analysis of tailings solids, pore water and pond water; ABA testing; and geotechnical input regarding dam stability. (Ministry of Northern Development and Mines)

Equity Silver Mine - Canada
SENES provided technical support to Equity Silver in the development of their reclamation proposal for high sulphide bearing waste rock piles. The Equity plan for closure of acid waste piles involved covering the piles with clay and treatment of residual runoff for as long a period as required. SENES developed a predictive, screening level model to assess acid generation rates with and without cover as well as for various types of cover material. The suitability of local materials was tested in the laboratory. The model results were used to support Equity's position that the current bonding cost provisions were adequate. (Equity Silver Mines Limited)

Les Mines Est Malartic Ltée and Les Terrains Aurifères Malartic Ltée, Quebec
SENES was retained by Lac Minerals to undertake an assessment of long term acid generation problems at two operating mines, Les Mines Est Malartic and Les Terrains Aurifères in northern Quebec. This work included modelling, cost analysis and assessment of the environmental benefits of various decommissioning options. In addition, SENES undertook an evaluation of water quality data collected at the sites and provided technical guidance on waste water treatment system operation. (LAC Minerals Ltd.)

Matachewan Gold Mine - Canada
SENES was retained as MCML's private consultant to provide site assessment and technical advice relating to environmental impacts, tailings management, remedial investigations and cleanup requirements for the failure of a 150,000 m3 tailings area and subsequent effluent discharge into Davidson Creek and the Montreal River near Matachewan, Ontario. SENES' responsibilities included developing the necessary programs to address the requirements of Orders issued by the MOE and MNR and participating in Environmental Appeal Board Hearings relating to appeal of the Orders. The assignment involved reviewing all of the investigation, evaluation, design and construction activities undertaken by the Regulatory authorities both during and after the failure. (Matachewan Consolidated Mines Limited)

Owl Creek Gold Mine Waste Rock Dump
SENES was part of a team which evaluated closure options for the Owl Creek gold mine in northern Ontario. The major concern was acid generation from the waste rock dump. SENES undertook an assessment of the acid generation and long-term nature of the acid problem and evaluated the environmental effects of several closure options. The data was integral in the mine's selection of pit disposal for resolution of a major environmental liability. (Falconbridge Gold Corporation)

URANIUM MINES

Agnew Lake Uranium Mine
Assistance was provided to Agnew Lake Mines in the receipt of approval to allow the Atomic Energy Control Board (AECB) decommissioning license to lapse. SENES completed a pathways analysis for the site and coordinated and submitted the final monitoring summary report for the five year transition monitoring phase. SENES also provided testimony before a hearing with the AECB in support of Agnew Lakes application which was approved. Ownership of the property now resides with the Province of Ontario. (Kerr Addison Mines Limited)

Atlas Tailings Pile Reclamation
SENES undertook a comparative screening level risk assessment of the proposed on-site reclamation plan and an alternative off-site reclamation option for this 10.5 million ton uranium tailings pile situated near Moab, Utah. The project included review of planned activities and assessments of associated radiological and non-radiological risks to the environment, public, and reclamation workers along with a comparison to the "no action" base case. In NRC's EIS assessment, staff concurred with the results of the SENES risk analysis. In addition to the risk analysis, SENES performed a review of the NRC regulatory and decision making framework, a review of Title I and Title II reclamation precedents and costs, carried out probabilistic cost estimate sensitivity analyses, and assisted Atlas and national counsel in development and presentation of public information and in producing comprehensive responses to NRC's DEIS and DTER. (Atlas)

Beaverlodge Uranium Mine
An engineering feasibility study was undertaken by SENES to assess the engineering requirements and the environmental and cost implications of several potential reclamation concepts for the ultimate close-out of the Beaverlodge uranium mine/mill facility in northern Saskatchewan. Reclamation concepts were developed for each component of the mine/mill facility including the tailings areas, tailings spills, waste rock piles, mine water sludges, mines, mill and ancillary facilities. Detailed pathways analyses were subsequently undertaken for selected reclamation options. Site-specific radiation measures, an evaluation of eating habits specific to the area, and a literature search of critical pathways parameters (e.g. water to fish transfer factors) were used to estimate the potential radiation exposures resulting from several reclamation options. A water quality model was developed mainly to simulate uranium and radium-226 levels over an extended timeframe for input to the pathways analysis.

The mine was successfully decommissioned and reclaimed. The Province of Saskatchewan and Eldorado Resources (now Cameco) have jointly participated in monitoring the transition years. The facility has largely performed as expected and negotiations are ongoing for transfer of the property back to the Crown. (Eldorado Resources Limited)

Chemical Reaction Modelling in Reactive Tailings
The primary objective of this work was to provide a model for predicting the long-term potential of acid generation in sulphidic tailings and for evaluating the effects on acid generation of alternative closeout concepts. The initial version of the model framework, known as the Reactive Acid Tailings Assessment Program (RATAP), was developed over the course of several projects under contract to the Canada Centre for Mineral and Energy Technology. The initial version of the model was designed to predict, on a long-term basis, the rate and the extent of acid generation and concomitant major geochemical events brought about by the chemical and microbial oxidation of pyrite in uranium tailings. This model was subsequently adapted to base metal tailings (RATAP.BMT) by including other sulphide ores such as arsenopyrite, galena, pyrrhotite and sphalerite. It consists of eight modules: initial inventory, soil temperature, oxidation kinetics, oxygen transport, sulphide oxidation, solute transport, aqueous speciation, and trace metal chemistry. The program can be run in a probabilistic or a deterministic manner. The original version of the model (RATAP) has been calibrated and validated extensively on pyritic uranium tailings. Partial validation of the modified computer model (RATAP. BMT) has been performed using field study data on the high sulphide tailings at Waite-Amulet in northeastern Quebec, some relevant data from pyritic uranium tailings investigations in the Elliot Lake area of northern Ontario, and laboratory observations. (Energy, Mines and Resources Canada; now Natural Resources Canada)

Collins Bay Uranium Mine
To assess the impact of a waste rock pile and open pit, laboratory scale leaching studies were designed and evaluated to determine the acid generation potential and the leachability of metals and radionuclides from the mine wastes. The project involved the development of a water quality model to assess reclamation strategies for the B Zone open pit and waste rock pile developed adjacent to Collins Bay on Wollaston Lake. The model simulated metal and radionuclide leaching from waste rock, mineralized waste and exposed ore and evaluated the potential benefits of reclamation alternatives. Pathways analyses to estimate the radiation exposure of local residents in the Wollaston Lake area of northern Saskatchewan were also prepared. (Cameco Corporation)

Denison Uranium Mine
SENES was a member of a team which developed and finalized the closure plan for the Denison mine/mill facilities and waste management area at Elliot Lake in northern Ontario. SENES' role is to complete all environmental components of the study, address acid generation controls and determine long-term environmental impacts, including modelling of the long-term dose to local inhabitants. The project also entailed the assessment of environmental and human health risks of accidental events and failures. (Denison Mines Limited)

Germany Uranium Mines
The re-unification of east and west Germany has provided an unparalleled challenge related to the publicly acceptable and cost effective environmental decommissioning of the former East German uranium mining and processing industry.

Since 1991 SENES has been advising the West German Federal and State Ministry's of the Environment on the complex environmental and scientific needs associated with decommissioning and rehabilitating lands and surrounding areas affected by the former East German uranium industry.

The decommissioning challenges related to this program are equal to or greater than any such task previously faced by the western mining industry. Key issues that need to be addressed include, among many:

• rehabilitation of more than 500 million m3 of waste rock;
• restoration of background natural waters which have been altered by more than 40 years of mining;
• cleanup and release of more than 8,800 acres of surface lands;
• stabilization and decommissioning of large scale settling basins containing chemical and radioactive contaminants.

In addition to the scientific and engineering needs, all of the above works must be addressed in a cost effective and timely manner within the complex infrastructure resulting from reunification of the two Germany's. Additionally, the work is complicated through the close proximity of large populations that will be affected by all actions.

Based on our recognized leadership in the area of radiological and environmental sciences, and a proven record of practical and effective application of these sciences and management practices, SENES Consultants Limited has played a key role in the assessment of the above issues and the development of strategies addressing the need for a long term integrated decommissioning plan that will meet with government and public acceptance. (Germany Environment Ministry)

Lacnor, Nordic, Pronto and Spanish American Uranium Mines
SENES completed an overview of closure options and costs for five inactive sites currently under long term care and maintenance in the Elliot Lake area of northern Ontario. The principal concerns at these properties pertained to long-term acid production from the sulphidic tailings and the ongoing operation of effluent treatment plants. (Rio Algom Limited)

Quirke and Panel Uranium Mines
SENES has participated in several investigations over the years aimed at the development of decommissioning plans for the Quirke and Panel uranium mines, mills, and associated waste management areas located in the Elliot Lake region of northern Ontario. This work has progressed through a review of options, preparation of an environmental and radiological pathways analysis, presentation of the decommissioning proposals to the Atomic Energy Control Board (AECB) and preparation of six environmental screening reports for submission to the AECB in accordance with the EARP process. All decommissioning activities and their attendant environmental impacts were identified; specific ameliorative and mitigative actions were recommended as required.

The decommissioning plan proposed for the Quirke tailings area involved the construction of an elaborate dam and dyke system to facilitate the flooding of the tailings management area, the institution of an interim mine dewatering program, and the implementation of radiological protection and decontamination methodologies. At Panel, the closure plan recommended for the tailings area entailed raising the perimeter dams to flood the tailings and thus control acid production and long-term contaminant migration of the receiving environment. (Rio Algom Limited)

Rabbit Lake Uranium Mine, Saskatchewan
SENES recently conducted a field program at the Rabbit Lake minesite followed by a laboratory program in order to characterize waste rock and mineralized waste, and to monitor the leachability of these materials. The program involved rock sampling, which included documentation of sample characteristics, field paste pH and conductivity measurements, and seepage water sampling. The laboratory program involved geochemical analyses and static tests (acid base accounting) followed by dynamic testwork (humidity cells and saturated columns) as well as leach tests and buffering tests. The interpretation of the results included evaluation of acid generation and leaching potential. The information from this assessment was subsequently used in geochemical modeling of the waste rock piles and in an environmental pathways analysis. (Cameco Corporation)

Stanleigh Uranium Mine
SENES prepared a conceptual closure plan in 1990 for the Stanleigh mine and mill facilities and waste management area. The closure plan was required as a condition of the Atomic Energy Control Board regulatory guide. The plan is presently under revision and being updated to reflect current developments from Rio Algom's Quirke and Panel closure plan studies. (Rio Algom Limited)

Stanrock Waste Management Area
The tailings in the Stanrock Waste Management Area (WMA) at Elliot Lake, Ontario, pose the usual acid mine drainage (AMD) problems associated with sulphidic mine wastes. Treatment of runoff and seepage from the WMA has been practised for two decades for neutralization of acidity, precipitation of heavy metals and removal of radionuclides. Faced with the prospect of continuing to treat the AMD for tens of years into the future, an investigation was undertaken to assess the costs and benefits of moving the tailings to a new facility or constructing new impermeable structures around the existing WMA, versus leaving the tailings in place and continuing to treat the AMD and handle the chemical sludge produced during treatment. The long-term acid generation potential of the tailings was modelled to assess how long into the future acid will continue to be produced from oxidation of the iron sulphide minerals. The investigation showed that the costs associated with all potentially viable options were high, although the benefits varied widely. (Denison Mines Limited)

Uranium Tailings Assessment Program Development
SENES developed, under contracts to the National Uranium Tailings Program administered by CANMET, Energy Mines and Resources Canada, a probabilistic computer model for predicting the long-term effects of sulphidic uranium mill tailings close-out options. The project involved: evaluation of three potential computer codes for carrying out a probabilistic assessment; delineation of the principal characteristics of a typical reference tailings site; selection of key pathways of radionuclide exposure of reference receptors; development of source term, environmental compartment, transfer, and dose models; assessment of the probability distributions and main attributes of the input parameters; evaluation of sensitivity and uncertainty analysis techniques for application to the output results; and execution of preliminary probabilistic assessments for selected tailings close-out options. The principal focus of the project was on the development of a flexible but user-friendly probabilistic assessment code. In addition to the concepts outlined above, the Uranium Tailings Assessment Program (UTAP) handles time dependency, spatial dependency, variable site characteristics, and numerous radioactive and non-radioactive contaminants. (Energy Mines and Resources Canada)