Community Newsletter June 2019 500,000 HOURS Denison Environmental Services (DES) has been working on achieving 500,000 no lost time injuries (LTI’s) since January 27, 2010. The last LTI was recorded on January 26, 2010 at a closed mine site in Territory. Since that time DES‘s staff have been working safely & diligently to regain a title of Safety Excellence. At the close of October 2018 our safety stats recorded a total of 499,184 hours without a lost time injury. On December 5th once the hours had been recorded by all staff we reached a total of 500,025.5 hours. The hours include all sites operated by Denison Environmental Services in , Quebec & Yukon. Each active staff member of “I’m unbelievably proud of our DES team for achieving 500,000 hours Denison Environmental Services received without a lost time injury and I‘m looking forward to celebrating future DES a Roots winter parka with our DES logo safety milestones as the team maintains its culture of safety through its on the chest and “500,000 no LTI’s” daily safety briefings and frequent safety training initiatives.” embroidered on the sleeve in recognition of this achievement. David Cates, President & CEO of Denison Mines Inc.

DENISON MINE SITE The site is located 16 km north of the City of Elliot Lake. When the site was operational, the complex consisted of a mine, a mill and two Tailings Management Areas (TMAs). Over its operational period between May 1957 and April 1992, Denison BEFORE AFTER produced a total of 63 million tonnes of uranium ore. Tailings were deposited and low security risks. flows of 200 L/s and peak flows of into two bedrock-lined basins: TMA-1 up to 600 L/s with barium chloride to (formerly Bear Cub Lake and Long Lake) The tailings are currently submerged precipitate radium. The Williams Lake and TMA-2 (formerly Upper Williams beneath a water cover approximately ETP was upgraded in 2016 to improve Lake). TMA-2 was filled in the early 1 m deep and are contained by the the overall condition of the building 1960s. natural topography and engineered and to replace aging equipment. The Decommissioning of the site involved containment dams. Surface drainage ETP is designed to precipitate radium the removal of underground equipment from TMA-2 flows through a spillway from any seepage of the TMA-2 site. All for reuse or recycling. Hazardous leading to TMA-1. Seepage from the top plant operations are automated and materials were removed for reuse corner of TMA-2 is treated downstream monitored on a 24 hour a day basis. or disposal. All surface facilities were at the Williams Lake Effluent Treatment Treated water is tested regularly and dismantled. A till cover was applied Plant (ETP). All other discharge is treated meets discharge criteria prior to being to the area and the site was graded at the single surface water discharge released to the Serpent River. Both and re-vegetated. Flooding was the spillway from TMA-1. It is expected that plants operate under a Uranium Mine preferred decommissioning option for over time, these ponds will become Decommissioning License issued by the TMA-1 and TMA-2. The flooding option wetlands. Canadian Nuclear Safety Commission. was anticipated to pose no negative The site is closed to ensure public safety effects on Quirke Lake or the Serpent The Denison ETP was upgraded in and to maintain the integrity of the River, no further outside disturbances 2013 and is designed to treat normal tailings management areas. ANNUAL REPORT SUMMARY DES ENVIRONMENTAL TEAM SAFETY TRAINING Denison Mines Inc. (DMI) continues there were no major projects that took HOURS OF OPERATION = 24/7 Denison Environmental to be committed to high quality of place on the Denison sites, however, Services — We want to work relating to operations, care here are some of the highlights of non- It doesn’t matter the time of day or night, and maintenance of the sites in Elliot routine tasks from 2018: in spring, summer, fall or winter, our share our safety culture Lake. DES, on behalf of DMI, performs Environmental team is actively monitoring with our community routine inspections and preventative ❑ A rain gauge was installed at the local closed mine sites. At minimum, all Did you know that Denison maintenance as required to ensure safe the TMA-1 ETP to allow for better operating sites are checked daily. Newer Environmental Services (DES) operations and reliable performance, monitoring during the technology has allowed many activities to offerslocal training for you and specifically of the tailings management summer; be monitored remotely, but many times site your employees? areas (TMAs) and the effluent treatment visits are still required, especially if weather Did you know that businesses ❑ plants (ETPs). This includes any work A secondary spill containment conditions are poor or when power failures with between 5 and 20 ranging from servicing, repairing or pad was installed at TMA-1 ETP at the occur. With a combined total of 75 years employees require a Health and includes regulatory licensing, permitting replacing equipment such as pumps, chemical reagent offloading area; experience in water monitoring, analysis Safety Representative? and reporting; site assessment and agitators, etc. to calibrating monitoring and treatment, our team is well-equipped Are your employees trained to ❑ End of life for some original rehabilitation; acid mine drainage and equipment such as pH meters and to manage the local sites. Meet the team: do their jobs safely? equipment meant that a new pump treatment, environmental performance flowmeters. These tasks are usually done WADE WIGGINS Environmental Did you know that DES offers was purchased and installed at the monitoring, data quality assessment locally by DES staff, but equipment is Manager: Knowledgeable in treatment the following courses and more: Dam M pump house on the Stanrock and facility inspection. As Environmental sometimes sent to a service provider if plant operations and environmental ❑ site, with the old one being serviced Coordinator, Valerie oversees the daily St. John Ambulance required. sustainability, Wade has completed many and kept available as a spare. sampling requirements and is responsible Emergency and Standard hours of training through Sacramento State Routine TMA maintenance is also an for compliance and reporting for the closed First Aid University and other sources, all related important aspect of long-term care sites in Elliot Lake. ❑ Basic Certification and maintenance. This includes dam to water and wastewater treatment. With Parts I and II over 30 years of experience operating and CHRIS MASSICOTTE Environmental maintenance, including herbicide ❑ WHMIS Another important aspect of long-term maintaining treatment plants, he is very Technician/Effluent Treatment Plant application and the removal of woody care and maintenance is the focused Operator: Chris joined the Denison ❑ Confined Space Entry vegetation, as well as managing beaver capable to supervise treatment operations and integrated performance monitoring downstream of the ETPs. Once this is Environmental team in 2016. Chris works ❑ Safe Driving/Driving activity on site, grading the access of any size as well as demonstrate excellent network that was developed by both complete, the resulting water is then operational, managerial and mechanical mostly in the field collecting and preparing Evaluations roads, and snow removal on these discharged to the SRW. and DMI. This program is aptitude skills. various samples for analysis and operating ❑ Book 7 Traffic Control same roads to ensure safe access on intended to monitor TMA performance treatment plants. While most of his tasks The data that is collected from these JODY STEFANICH Environmental Training site. Most maintenance work that is and quality of water being discharged are in the field, he is also responsible to programs is reviewed regularly, and Coordinator: Jody has spent most of his ❑ Violence and Harassment required at the site is on a schedule (i.e. to the Serpent River Watershed (SRW) prepare various technical reports for the is also reviewed in great depth every career working at the Elliot Lake mine sites. in the Workplace calibration of flowmeters) and is tracked as well as assess the recovery of the Elliot Lake closed sites. Chris shares a role five years as part of an integrated Jody has spent over 25 years in the field, ❑ in a preventative maintenance tracking receiving environment (i.e. the SRW). As in routine facility inspections. CSA-required fit testing assessment in a State of the Environment collecting various forms of samples and system. part of this program, DES operates three If you need a course that is not report (SOE). The monitoring programs preparing these samples for laboratory CHARLA SHAIN Environmental Occasionally larger projects are ETPs on the DMI sites in the Elliot Lake listed, give us a call. are intended to evolve over time in analysis, water level management Technician/Effluent Treatment Plant required that are outside of the realm area. These ETPs operate as required to We can come to your location response to changes observed in the and treatment plant operation. As Operator: Charla is the newest member of routine care and maintenance. These treat water coming from the TMAs before or you can send your employees watershed and TMA conditions. The Environmental Coordinator, Jody oversees of the Environmental team, joining us in may include construction projects such being released into the environment via to us. programs are reviewed every five years the Field Staff, and is responsible for April 2019. Charla will also spend most as improving buildings on site. In 2018, the SRW. This involves the collection of and modified based on previous findings. compliance and reporting for the closed of her time in the field collecting and TMA surface water or seepage into either Currently, the Elliot Lake sites are in the sites in Elliot Lake. preparing various samples from the Elliot basins or collection ditches, depending Call us today at fourth cycle of monitoring (2015-2019). Lake closed sites. Under the mentorship on the nature of the site, and directed to VALERIE KILP Environmental Coordinator: DES, Rio Algom and other third party of both Environmental Coordinators, the ETPs. This water is then treated with Valerie has 14 years of experience in consultants are currently working on the Charla’s responsibilities will increase as she 705-848-9191 lime and/or barium chloride reagents the environmental field. Her experience most recent SOE, as well as the next cycle becomes comfortable with each task. in order to neutralize pH in the water of the monitoring program (i.e. Cycle 5). and remove contaminants by binding to them and forming particles that are Overall, TMAs are performing as settled out of the water in settling ponds predicted, with water quality improving WORKING TOGETHER IN OUR COMMUNITY over time. Water quality results from 2018 support this statement, with Denison recognizes the importance we work — including the Sudbury water quality results from discharge of community responsibility and Food Bank, the Whitehorse Food Bank, water meeting government guidelines awareness. We support local students Maison Saint-André Abitibi Ouest and established for the protection of aquatic by providing educational bursaries to the Elliot Lake Emergency Food Bank. life. It is important to note that water graduates from Elliot Lake Secondary We provide in-kind manpower to leaving the sites must meet the discharge School, École secondaire Villa Française assist local community groups like the limits for certain parameters set out in des Jeunes and Serpent River First Chamber of Commerce. the decommissioning licenses issued by Nation. Denison is a member of the City of the Canadian Nuclear Safety Commssion. We participate in the Adopt-A- Elliot Lake’s Emergency Management In 2018, all water leaving the Denison Highway program, looking after a Committee and acts as a resource sites in Elliot Lake met these criteria. portion of Highway 108. We support on the Shared Use Trails the local food banks in the cities where committee. www.denisonenvironmental.com HEALTH AND SAFETY WHY DO OUR SITES What you can see behind our locked SAY NO TRESPASSING? gates are not open fields, or picturesque lakes. What you see are tailings Denison would like to remind everyone management areas. When closing the that our sites are not just big empty mines, the tailings were covered with spaces. They are closed uranium mine water or vegetation. Uranium tailings sites with large tailings management are the radioactive, sand-like materials areas. These areas were designed to left over from the uranium milling isolate the tailings from the surrounding process. When the tailings are covered, environment for a very long time. it helps to reduce acid generation and These sites use man-made barriers the release of gamma radiation and place. Over time subsidence areas (such as dams) to contain the tailings. radon gas. Although the site roads were (eg. sink holes) appear due to the The dams are designed to ensure that constructed using clean fill, trespassers instability of the underground workings. groundwater and surface water is that walk or drive off the roads may Denison Environmental Services (DES) diverted from the tailings to prevent any inadvertently take home radioactive staff inspect the properties regularly, contamination. material in their tires, on their shoes or but this is an unpredictable hazard. The Canadian Nuclear Safety in the paws of their pets. Water management is one of our key Commission (CNSC) is responsible for Our Environmental and Maintenance roles on the sites. We have to ensure a regulating and licensing all uranium staff are on and off these sites, working sufficient flow of water in many areas. mining operations in Canada. The every day. We drive trucks, transports Part of this process is the control of CNSC regulates the use of nuclear and other large mobile equipment to nuisance beaver activity through traps. energy and materials to protect health, complete our daily tasks, and we may Traps are set below the water and are safety, security and the environment not know you are walking right around not visible from shore. These traps can and to disseminate objective scientific, the corner. be a danger to those owners who insist technical and regulatory information to on walking dogs off leash, and on closed Although the sites have been the public. It is under our CNSC mine site properties. license that our sites are closed to decommissioned, with all mine features the public. All hikers, dog walkers, capped or blocked, facility structures There are many established trails and ATV‘ers and other unauthorized demolished and the sites landscaped roads in the Elliot Lake area that are not people who enter the sites are and revegetated, dangers still remain. located on a closed mine site. Please tresspassing. Some of the structures were buried in obey the signs and stay safe. STAY INFORMED Denison Mines invites you to stay We would like to hear your thoughts I would like to know more about: informed about our activities within the about our performance in the Serpent River Watershed by: operation, care and maintenance of our ❑ Attending a mine site tour, closed mine sites. Please call us or send organized annually by the City of Elliot us a note. You can use the attached Lake’s Nuclear and Mining Museum form and drop it off to our office. as part of the Uranium Heritage Days We will respond as quickly as possible. activities Question(s): ❑ Watching our presentation to Elliot Lake Council, in person, on the local TV station or on the City‘s website ❑ Reviewing our technical reports, YOUR CONTACT INFORMATION: available at the Elliot Lake Library or at www.denisonenvironmental.com Name: ❑ Reading this annual newsletter Phone: ❑ Contacting us using this response form. Email:

SEND YOUR RESPONSE FORM TO: Denison Mines Inc. Attn: Janet Lowe, General Manager, Denison Environmental Services 1 Horne Walk, Suite 200, Elliot Lake, ON, P5A 2A5 • 705-848-9191 • [email protected]