VANCOUVER, Oct. 26, 2016 - NexGen Energy Ltd. ("NexGen" or the "Company") (TSX: NXE, OTCQX: NXGEF) is pleased to announce it has received positive preliminary metallurgical results from the Arrow Deposit, which is located its 100% owned, Rook I property, Athabasca Basin, Saskatchewan.
A bench scale metallurgical test program was designed by Grant Feasby, M.Sc., and completed by the Saskatchewan Research Council (SRC) laboratory in Saskatoon to determine the preliminary leaching process, raffinate solution composition, purity of yellow cake product, and tails settling. Tests confirmed that the Arrow Deposit is a "clean" uranium resource, and is amenable to favourable metallurgical processing and waste management practices.
Highlights:
- Leaching tests yielded high uranium recoveries exceeding 98%, and were obtained with mild acid conditions (pH 1.1 to 1.5) and modest acid consumption in a short time period (8 hours or less).
- The Arrow Deposit composite head sample returned 4.41% U3O8 with very low deleterious metal content of 0.011% arsenic and 0.005% selenium.
- Gold and silver assayed 0.8 g/t and 29.5 g/t, respectively.
- Important parameters from the composite head sample include <0.01% inorganic carbon indicating no carbonate, and sulphide content of 0.46%, which is low compared to other high grade resources in Saskatchewan.
- Results of the solvent extraction and uranium precipitation tests using conventional methods indicated very high recoveries and minimal uranium losses to solvent extraction raffinate and to barren solution.
- High purity yellowcake product was produced by stripping pregnant solution with ammonium sulfate-ammonium hydroxide solution. Activated carbon treatment was successful in reducing the molybdenum impurity to an acceptable concentration.
- Tails settling rates increased with the use of a flocculant called Magnafloc 351, which is widely used in the counter-current decantation circuits of uranium mines in Saskatchewan.
- A medium level of energy is required to crush and grind the composite sample with a work index of 16.5 kwh/tonne, and a reasonable grind size of P100 = 300 micrometers optimized uranium liberation.
Leigh Curyer, Chief Executive Officer commented: "These positive preliminary results demonstrate another highly favourable technical aspect of Arrow and will be incorporated into our development studies that have been conducted throughout 2016 and will continue to work on in 2017. These studies include environmental, geotechnical, metallurgical and site characterization which will form the basis of, and culminate in, the publication of the maiden pre-feasibility study on the Arrow Deposit scheduled in H2 2017."
The 55 kg composite sample representing the Arrow resource was blended and homogenized from 131 core assay reject samples that yielded a specific gravity of 2.70 g/cm3. The composite head sample returned the results shown in Table 1 below.
Table 1: Chemical Composition of the Composite Sample
| Component | Content | Assay Method | Comment | |
| % | ppm | |||
| U3O8 | 4.41 | U3O8 ICP | ||
| Au | 0.80 | Fire Assay | Potentially recoverable | |
| Ag | 29.50 | ICP1 TD | Potentially recoverable | |
| Th | 66.50 | ICP MS TD | relatively low 0.3 Bq/g | |
| U | 36850 | |||
| Mo | 2225 | Mo recovery with activated carbon | ||
| Ni | 184 | |||
| Pb | 3660 | Mostly radiogenic Pb | ||
| Co | 114 | |||
| Cu | 1370 | |||
| V | 592 | |||
| Zn | 23 | |||
| Total Rare Earth Oxides | 0.20 | Potentially recoverable | ||
| As | 106 | Multi-Element ICP-AR | Very low deleterious metal | |
| Se | 52 | Very low deleterious metal | ||
| Hg | < 1 | Non-detectable deleterious metal | ||
| Graphitic C | 1.54 | LECO | As graphite | |
| Inorganic C | < 0.01 | Indicates no carbonate content | ||
| Organic C | 0.21 | |||
| Sulphate S | 0.13 | |||
| Sulphide S | 0.46 | Very low sulphide content | ||
From a processing and environmental management perspective these sample analyses indicate that the Arrow Deposit is suitable for conventional acid leaching, solvent extraction and uranium production as ammonium diuranate (yellowcake) or uranyl peroxide (UO4 2H2O). The overall metallurgical test program confirms that a high purity uranium product can be produced, which meets all of the specifications from ASTM C967-13 "Standard Specifications for Uranium Ore Concentrate". All of the sampling, analytical and test work conducted during this program has been reviewed and approved by Grant Feasby, M.Sc.
Technical Information
All scientific and technical information in this news release has been prepared by or reviewed and approved by Mr. Garrett Ainsworth, P.Geo., Vice President – Exploration & Development for NexGen. Mr. Ainsworth is a qualified person for the purposes of National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101"), and has verified the sampling, analytical, and test data underlying the information or opinions contained herein by reviewing original data certificates and monitoring all of the data collection protocols.
For details of the Rook I Project including the quality assurance program and quality control measures applied and key assumptions, parameters and methods used to estimate the mineral resource set forth above please refer to the technical report entitled "Technical Report on the Rook 1 Property, Saskatchewan, Canada" dated effective April 13, 2016 (the "Rook 1 Technical Report") prepared by Mark B. Mathisen and David Ross, each of whom is a "qualified person" under NI 43-101. The Rook I Technical Report is available for review under the Company's profile on SEDAR at www.sedar.com.
About NexGen
NexGen is a British Columbia corporation with a focus on the acquisition, exploration and development of Canadian uranium projects. NexGen has a highly experienced team of uranium industry professionals with a successful track record in the discovery of uranium deposits and in developing projects through discovery to production.
NexGen owns a portfolio of highly prospective uranium exploration assets in the Athabasca Basin, Saskatchewan, Canada, including a 100% interest in Rook I, location of the Arrow Discovery in February 2014, Bow Discovery in March 2015 and Harpoon Discovery in August 2016. The Arrow Deposit's maiden Inferred mineral resource estimate is 201.9 M lbs U3O8 contained in 3.48 M tonnes grading 2.63% U3O8.
SOURCE NexGen Energy Ltd.
