- Achieved the commercial-scale production flowrate assumed in the Pre-Feasibility Study ("PFS") prepared for the Project in 2018.
- Demonstrated hydraulic control of injected solution during ion tracer test – reporting no elevated values of the tracer element in the monitoring wells surrounding the commercial-scale test pattern.
- Established breakthrough times between injection and recovery wells, spaced 5 to 10 meters apart, that are consistent with previous 'Proof of Concept' hydrogeological modelling conducted by
Petrotek Corporation ("Petrotek"). - Completed 'clean-up phase' following tracer test demonstrating ability to remediate the test pattern – reducing tracer concentrations to as low as 4% of peak test levels within eight days of remediation.
While our previous test work has provided considerable support for the use of ISR at
With the field test completed and the Company well capitalized, our technical team is moving full-steam ahead with the development of our field plans for 2022 while also supporting the recent launch of the formal feasibility study process."
The 2021 ISR Field Test program was designed to further increase confidence and reduce risk in the application of the ISR mining method at
This press release constitutes a "designated news release" for the purposes of the Company's prospectus supplement dated
Test Pattern Installation
A test pattern consisting of five commercial-scale wells ("CSWs"), including GWR-038 to GWR-042, and 10 additional small diameter monitoring wells ("MWs") (together described as the "Test Pattern"), was successfully installed within the Phase 1 area of the
Three methods of permeability enhancement were successfully evaluated on the five CSWs, with post permeability enhancement testing resulting in observed improvement in hydraulic responses and inter-well connectivity within the Test Pattern. These results exhibit and confirm the ability to engineer additional access to the natural permeability within the deposit. Permeability enhancement methods included the use of the MaxPERF drilling tool as well as wireline-conveyed tools designed to perforate and stimulate well production using a controlled propellant. The wireline tools can effectively "clean out" restricted pathways within the well screen, well bore, and the geological formation and provide increased flow rates in the wells by intersecting and connecting to the naturally occurring fractures within the ore zone.
Twenty single-well injection tests were completed on the Test Pattern to evaluate natural permeability and the efficiency of permeability enhancement methods deployed in the CSWs. Nine single-well pump tests were completed amongst the five CSWs and four of the MWs to evaluate permeability, sustainable pumping rates, hydraulic connectivity, and baseline groundwater conditions. Importantly, testing showed good hydraulic connection between the CSWs in the ore zone horizon and no significant responses in any of the MWs in overlying or underlying horizons (see Figure 2). One step-rate injection test was conducted on the center CSW (GWR-040) to evaluate hydraulic connectivity, maximum injection rates and injection pressures.
Full-Scale Well Pattern Pump and Injection Test
A full-scale well pattern injection and pumping test was conducted to determine hydraulic connectivity for the Test Pattern as a whole, and to evaluate potential production rates for the pattern. The test was run as a modified 4-spot pattern as there was an unanticipated failure of the submersible pump in GWR-042. During the test, injection rates were matched to pumping extraction rates for balanced flow in the Test Pattern. Pumped groundwater from each of the outer wells (GWR-038, GWR-039, and GWR-041) was recycled for injection in the center well (GWR-040) to create a closed system. Production rates for the Test Pattern achieved a sustainable rate of 45.3 litres per minute ("L/min") injection in GWR-040 with minimal pressure on surface balanced with 15.1 L/min extraction at each GWR-038, GWR-039 and GWR-041. This test fundamentally achieved the 50 L/min flow rate assumed in the PFS for an operating well pattern. Hydraulic control of the Test Pattern was confirmed by no significant hydrologic responses observed in any of the overlying or underlying monitoring wells.
Ion Tracer Test
Following the full-scale injection and pumping test, an ion tracer test was completed using the 4 functional CSWs in the Test Pattern. Flow rates were run at the same levels as the full-scale well pattern test with 45.3 L/min injection at the center well and a balanced extraction flow of 15.1 L/min at each of the three outer wells. The ion tracer, consisting of a 15% concentration of potassium chloride (KCl) by weight, was injected as an initial slug into the Test Pattern at GWR-040, followed by a chase phase involving the recirculation of water extracted from the three outer wells (closed system). The chase phase continued until peak concentrations of the ion tracer, measured in total dissolved solids ("TDS"), were observed at the three extraction wells (GWR-038, GWR-039 and GWR-041), followed by a decline in TDS prior to commencement of a remediation test.
Breakthrough of the ion tracer, as observed by an increase in the TDS, occurred at the three extraction wells within 9 hours (GWR-039), 12 hours (GWR-041), and 14 hours (GWR-038). These breakthrough times observed during the field test are consistent with previous hydrogeological modelling conducted by Petrotek (see press release dated
Remediation Test
After completion of the ion tracer test, a "clean-up" remediation test was conducted to simulate the ability to remove injected fluid from the Test Pattern. For this test, injection was halted at the center well (GWR-040) and the three extraction wells were pumped to remove the remaining injected ion tracer. Tracer concentrations measured during the eight-day clean-up simulation, as observed by field TDS measurements, declined to as low as 13% of the peak TDS value in GWR-038, 11% of the peak TDS value in GWR-041, and 4% of the peak TDS value in GWR-039.
Hydrogeological Monitoring
Monitoring during the ion tracer test and subsequent clean-up test included: 376 field measurements of TDS from the CSW extraction wells to identify tracer concentrations; logging of water levels in each of the CSWs along with all of the surrounding MWs at five-minute intervals; logging of TDS values at five-minute intervals in the three overlying MWs to confirm the absence of any tracer concentrations in the overlying horizons; and daily groundwater sampling to send for lab analysis to confirm TDS values measured in the field and the exact concentration of the KCl tracer.
The ability to maintain hydraulic control was established by sampling the three overlying MWs for TDS values before and after the ion tracer test. No elevated values in TDS were observed during the test, thus confirming there was no migration of the tracer to overlying horizons.
Data collected as part of the 2021 field program will be utilized to update the
Ongoing Permeameter Analysis
In addition to the hydrogeological tests described above, over 1,000 drill core samples were collected from historic holes, re-logged for hydrogeologic characteristics, and analyzed for permeability utilizing the permeameter on-site. Samples were selected to ensure the database of on-core permeability results included representative samples from all of the planned mining phases at
COVID-19
The Company is committed to ensuring that the Wheeler River site is a safe operating environment for its staff and contractors and that the Company's field activities do not compromise the health and safety of the residents of northern Saskatchewan. In 2020, the Company's
The 2021 ISR Field Test was completed over an eight-month period and involved the on-site support of over 100 different staff and contractors. COVID-19 rapid testing was completed regularly at the site, with no positive cases reported during the entire program. These results demonstrate the effectiveness of the Company's COVID-19 protocols and helped to ensure that the extensive scope of the 2021 ISR Field Test was completed on schedule.
Groundwater Measurement and Sampling Procedures
Individual wells are monitored and logged at five-minute intervals utilizing In-Situ LevelTROLL 700 Data Logger transducers installed on cables below the water table, providing water level, water pressure, and temperature data based on factory calibrations. Manual water level readings are recorded using a
For a description of the data verification, assay procedures and the quality assurance program and quality control measures applied by Denison, please see Denison's Annual Information Form dated March 26, 2021 filed under the Company's profile on SEDAR at www.sedar.com.
About Phoenix Phase 1
As outlined in the Company's news release dated
Phase 1 of the deposit is estimated to contain approximately 22.2 million pounds U3O8 (37,242 tonnes at 27.1% U3O8, above a cut-off grade of 0.8% U3O8) in Probable mineral reserves. Based on current designs, the Company estimates approximately 6.6 million pounds U3O8 (7,717 tonnes at 39.2% U3O8, above a cut-off grade of 0.8% U3O8) in Probable mineral reserves are contained within the expected operating perimeter of the CSWs in the Test Pattern (see Figure 1). These estimates are derived as a direct subset of those reported in the Technical Report titled "Pre-feasibility Study for the
About Wheeler River
Wheeler River is the largest undeveloped uranium project in the infrastructure rich eastern portion of the
A PFS was completed for Wheeler River in 2018, considering the potential economic merit of developing the
Further details regarding the PFS, including additional scientific and technical information, as well as after-tax results attributable to Denison's ownership interest, are described in greater detail in the NI 43-101 Technical Report titled "Pre-feasibility Study for the
Denison suspended certain activities at Wheeler River during 2020, including the EA process, which is on the critical path to achieving the project development schedule outlined in the PFS. While the EA process has resumed, the Company is not currently able to estimate the impact to the project development schedule outlined in the PFS, and users are cautioned against relying on the estimates provided therein regarding the start of pre-production activities in 2021 and first production in 2024.
About Denison
Denison is a uranium exploration and development company with interests focused in the
Through its 50% ownership of JCU, Denison holds additional interests in various uranium project joint ventures in
Denison is also engaged in mine decommissioning and environmental services through its Closed Mines group (formerly Denison Environmental Services), which manages Denison's
Follow Denison on Twitter @DenisonMinesCo
Qualified Persons
The disclosure of scientific or technical information related to certain hydrogeological results and interpretations (including the hydrogeological investigations carried out as part of the 2021 ISR Field Test and associated analysis) contained in this release has been reviewed and approved by Mr.
Cautionary Statement Regarding Forward-Looking Statements
Certain information contained in this news release constitutes 'forward-looking information', within the meaning of the applicable
Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as 'plans', 'expects', 'budget', 'scheduled', 'estimates', 'forecasts', 'intends', 'anticipates', or 'believes', or the negatives and/or variations of such words and phrases, or state that certain actions, events or results 'may', 'could', 'would', 'might' or 'will be taken', 'occur', 'be achieved' or 'has the potential to'.
In particular, this news release contains forward-looking information pertaining to the following: the interpretation of results of the ISR field program, including expectations regarding further de-risking of the ISR mining method; Denison's capitalization to enable further studies; the initiation of the FS and the planned scope, elements, and objectives of the FS; other evaluation activities, objectives and expectations, including the permeameter analysis and the ongoing EA and related processes; the results of the PFS and expectations with respect thereto, including the mineral resource estimates and project designs disclosed to-date and the ability to maintain or build upon such designs; other development and expansion plans and objectives; Denison's COVID-19 and other health and safety protocols; and expectations regarding its joint venture ownership interests and the continuity of its agreements with its partners and third parties.
Forward looking statements are based on the opinions and estimates of management as of the date such statements are made, and they are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Denison to be materially different from those expressed or implied by such forward-looking statements. For example, the modelling and assumptions upon which the work plans are based may not be maintained after further testing or be representative of actual conditions within the
Accordingly, readers should not place undue reliance on forward-looking statements. The forward-looking information contained in this news release is expressly qualified by this cautionary statement. Any forward-looking information and the assumptions made with respect thereto speaks only as of the date of this news release. Denison does not undertake any obligation to publicly update or revise any forward-looking information after the date of this news release to conform such information to actual results or to changes in Denison's expectations except as otherwise required by applicable legislation.
Cautionary Note to United States Investors Concerning Estimates of Mineral Resources and Mineral Reserves: This press release may use terms such as "measured", "indicated" and/or "inferred" mineral resources and "proven" or "probable" mineral reserves, which are terms defined with reference to the guidelines set out in the
Figure 1: Plan Map Showing Location of Phoenix Deposit (Phase 1) – ISR Test Pattern
Figure 2: Cross Section Showing Location of Test Pattern Wells at Phase 1
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