NexGen Energy Intersects 41 Metres of Total Composite Mineralization at Rook I Property

VANCOUVER, Oct. 18, 2017 /CNW/ - NexGen Energy Ltd. ("NexGen" or the "Company") (TSX:NXE, NYSEMKT:NXE) is pleased to report radioactivity results for sixteen holes from South Arrow as part of our on-going summer drilling program on our 100% owned, Rook I property, in the Athabasca Basin, Saskatchewan.

Aggressive step out drilling at the recently discovered South Arrow has intersected significant off-scale radioactivity in multiple holes, and has extended the strike length and vertical extent of high grade mineralization to 240 m and 185 m, respectively. High grade uranium mineralization occurs as accumulations of semi-massive to massive pitchblende similar to that seen in the High Grade Domains of the Arrow Deposit.

• AR-17-166c1 (250 m up-dip and southwest of discovery hole AR-17-151c1) intersected 41.0 m of total composite mineralization including 6.2 m of total composite off-scale radioactivity (>10,000 to >61,000 cps) within a 54.0 m section (182.5 to 236.5 m). This is the shallowest significant off-scale mineralization encountered anywhere on the Rook I property.
• AR-17-160c1 (203 m up-dip and southwest of discovery hole AR-17-151c1) intersected 30.0 m of total composite mineralization including 3.5 m of total composite off-scale radioactivity (>10,000 to >61,000 cps) within a 157.0 m section (192.0 to 349.0 m).
• AR-17-163c1 (190 m up-dip and southwest of discovery hole AR-17-151c1) intersected 23.0 m of total composite mineralization including 2.2 m of total composite off-scale radioactivity (>10,000 to >61,000 cps) within a 109.5 m section (162.5 to 272.0 m).

Two diamond drill rigs remain in operation at South Arrow as the Company continues to aggressively and systematically test this encouraging new zone. A total of eighteen assays remain pending.

A South Arrow longitudinal section and plan map with drill hole locations are shown in Figures 1 and 2.

Garrett Ainsworth, Vice-President, Exploration and Development, commented: "Drill hole AR-17-160c1 represents a highly successful 203 m step out to the southwest from the initial discovery hole at South Arrow. The ability to hit high grade mineralization on an aggressive step out of this distance has been a common characteristic of the Arrow Deposit, which is located 400 m to the north of South Arrow on a separate conductor. South Arrow contains a broad alteration halo that surrounds multiple parallel stacked mineralized zones, which are two important features observed at the Arrow Deposit. Hole AR-17-166c1 at South Arrow has encountered the shallowest significant high grade mineralization anywhere on the Rook I property to date."

Leigh Curyer, Chief Executive Officer, commented: "The scale of these South Arrow results are very exciting considering its very early in the discovery stage. They are unprecedented on the Rook I property and highlight the vast discovery potential of our dominant portfolio in the Southwest Athabasca Basin. An additional 5,000m of drilling has been allocated to South Arrow before the conclusion of the 2017 drilling program."

Table 1: South Arrow Drill Hole Data

Parameters:

• Maximum internal dilution 2.00 m downhole
• All depths and intervals are metres downhole, true thicknesses are yet to be determined
• "Anomalous" means >500 cps (counts per second) total count gamma readings by gamma scintillometer type RS-120
• "Off-scale" means >10,000 cps (counts per second) total count gamma readings by gamma scintillometer type RS-120
• Where "Min cps" is <500 cps, this refers to local low radiometric zones within the overall radioactive interval
• Directional drilling has often resulted in mineralization intersected at a more favourable and shallower dip

South Arrow Drilling

AR-17-151c3

Hole AR-17-151c3 was a directional hole that departed pilot hole AR-17-151c1 at a depth of 123 m. It was designed to test the South Arrow zone 30 m above AR-17-151c1. Directional drilling was initiated at 144 m and the mineralized horizons were intersected at an inclination of -61°. Basement lithologies were intersected from the top of hole and dominantly consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, and foliation-controlled pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 3.0 m including 0.15 m of off-scale radioactivity (>10,000 to 18,000 cps) was intersected within a 12.0 m section (280.5 to 292.5 m) before the hole was terminated at 405 m.

AR-17-152c1

Hole AR-17-152c1 was a directional hole collared from surface at an angled orientation (-70°) to the northwest (327° azimuth). It was designed to test the South Arrow zone 40 m southwest of AR-17-151c1. Directional drilling was initiated at 132 m and the mineralized horizons were intersected at an inclination of -58°. The hole intersected Athabasca Group sandstones between 91.3 m and the unconformity at 96.4 m. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 2.0 m was intersected between 294.5 m and 303.0 m. The hole was terminated at 456.5 m.

AR-17-152c2

Hole AR-17-152c2 was a directional hole that departed pilot hole AR-17-152c1 at 148 m. It was designed to test the South Arrow zone 50 m below AR-17-152c1. Directional drilling was initiated at 159 m and the mineralized horizons were intersected at an inclination of -68°. Basement lithologies were intersected from the top of the hole that included semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 8.0 m was intersected within a 149.0 m section (333.0 to 482.0 m) before the hole was terminated at 540.5 m.

AR-17-153c1

Hole AR-17-153c1 was a directional hole collared from surface at an angled orientation (-67°) to the northwest (327° azimuth). It was designed to test South Arrow zone 50 m down-dip from AR-17-151c2. Directional drilling was initiated at 126 m and the mineralized horizons were intersected at an inclination of -61°. The hole intersected Athabasca Group sandstones between 94.9 m and the unconformity at 97.8 m. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, fracture-hosted, foliation-controlled, and mineral replacement style pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 6.5 m including 0.55 m of off-scale radioactivity (>10,000 to 21,000 cps) was intersected within an 82.0 m section (373.0 to 455.0 m). The hole was terminated at 546 m.

AR-17-153c2

Hole AR-17-153c2 was a directional hole that departed pilot hole AR-17-152c1 at 294 m. Directional drilling was initiated at 126 m and the mineralized horizons were intersected at an inclination of -69°. It was designed to test the South Arrow zone 50 m down-dip of AR-17-153c1. Basement lithologies were intersected from the top of the hole that included semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. Continuous mineralization of 9.0 m was intersected between 411 and 420 m before the hole was terminated at 558.5 m.

AR-17-157c1

Hole AR-17-157c1 was a directional hole collared from surface at an angled orientation (-70°) to the northwest (327° azimuth). It was designed to test the South Arrow zone 50 m down-dip of AR-17-152c2. Directional drilling was initiated at 198 m and the mineralized horizons were intersected at an inclination of -66°. The hole intersected Devonian-aged sandstones between 87.9 m and 93.7 m. No Athabasca Group sandstones were encountered. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 3.0 m was intersected within a 147.0 m section (385.0 to 532.0 m) before the hole was terminated at 597.5 m.

AR-17-157c2

Hole AR-17-157c2 was a directional hole that departed pilot hole AR-17-157c1 at 203 m. It was designed to test the South Arrow zone down-dip of AR-17-157c1. Directional drilling was initiated at 264 m and the mineralized horizons were intersected at an inclination of -70°. Basement lithologies were intersected from the top of the hole that included semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 9.0 m was intersected within a 178.5 m section (400.5 to 579.0 m) before the hole was terminated at 639.0 m.

AR-17-158c1

Hole AR-17-158c1 was a directional hole collared from surface at an angled orientation (-70°) to the northwest (327° azimuth). It was designed to test the South Arrow zone 50 m down-dip and northeast of AR-17-153c2. Directional drilling was initiated at 150 m and the mineralized horizons were intersected at an inclination of -65°. The hole intersected Cretaceous-aged mudstone between 71.8 m and 90.8 m. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 9.0 m was intersected within a 22.0 m section (438.5.0 to 460.5 m) before the hole was terminated at 600.0 m.

AR-17-158c2

Hole AR-17-158c2 was a directional hole that departed pilot hole AR-17-158c1 at 173 m. It was designed to test the South Arrow discovery 50 m down-dip of AR-17-158c1. Directional drilling was initiated at 189 m and the mineralized horizons were intersected at an inclination of -72°. Basement lithologies were intersected from the top of the hole that included semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected disseminated and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 3.5 m was intersected within a 36.5 m section (486.5 to 523.0 m) before the hole was terminated at 579.5 m.

AR-17-160c1

Hole AR-17-160c1 was collared from surface at an angled orientation (-68°) to the northwest (327° azimuth). It was designed to test the South Arrow zone 190 m southwest of AR-17-151c3. The hole intersected Athabasca Group sandstones between 92.7 m and the unconformity at 97.6 m. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, vein-style, and semi-massive pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 30.0 m including 3.5 m of off-scale radioactivity (>10,000 to >61,000 cps) was intersected within a 157.0 m section (192.0 to 349.0 m) before the hole was terminated at 393.0 m.

AR-17-162c1

Hole AR-17-162c1 was collared from surface at an angled orientation (-68°) to the northwest (315° azimuth). It was designed to test the South Arrow zone 40 m up-dip of AR-17-162c1. The hole intersected Athabasca Group sandstones between 96.0 m and the unconformity at 96.9 m. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, vein-style, and semi-massive pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 10.0 m including 0.85 m of off-scale radioactivity (>10,000 to 56,000 cps) was intersected within a 111.5 m section (145.0 to 256.5 m) before the hole was terminated at 442.5 m.

AR-17-163c1

Hole AR-17-163c1 was collared from surface at an angled orientation (-68°) to the northwest (315° azimuth). It was designed to test the South Arrow zone 50 m down-dip of AR-17-160c1. The hole intersected Athabasca sandstone between 92.25 m and the unconformity at 96.2 m. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, vein-style, and semi-massive pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 23.0 m including 2.2 m of off-scale radioactivity (>10,000 to >61,000 cps) was intersected within a 109.5 m section (162.5 to 272.0 m) before the hole was terminated at 438.0 m.

AR-17-165c1

Hole AR-17-165c1 was collared from surface at a near vertical orientation (-80°) to the northwest (315° azimuth). The primary target was flat lying mineralization at the unconformity 55 m up-dip from AR-17-162c1. Basement-hosted mineralization was also expected immediately below the unconformity. No Athabasca Group sandstones were intersected indicating that the unconformity has been eroded at this location. Basement lithologies consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, and fracture-hosted pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 2.0 m was intersected between 116.0 m and 118.0 m before the hole was terminated at 249.5 m.

AR-17-166c1

Hole AR-17-166c1 was collared from surface at an angled orientation (-70°) to the northwest (310° azimuth). It was designed to test the South Arrow zone 50 m southwest of AR-17-160c1. Directional drilling was initiated at 120 m and the mineralized zones were intersected at an inclination of -75° The hole intersected basement lithologies beginning at 94.2 m which consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, vein-style, and semi-massive pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 41.0 m including 6.2 m of off-scale radioactivity (>10,000 to >61,000 cps) was intersected within a 54.0 m section (182.5 to 236.5 m) before the hole was terminated at 303.0 m.

AR-17-168c1

Hole AR-17-168c1 was collared from surface at an angled orientation (-68°) to the northwest (315° azimuth). It was designed to test the South Arrow zone 50 m down-dip from of AR-17-163c2. Directional drilling was initiated at 99 m and the mineralized zone was intersected at an inclination of -55° The hole intersected basement lithologies beginning at 84.4 m which consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 1.5 m was intersected beginning at 315.0 m before the hole was terminated at 471 m.

AR-17-169c1

Hole AR-17-169c1 was collared from surface at an angled orientation (-68°) to the northwest (315° azimuth). It was designed to test the South Arrow zone 50 m up-dip from of AR-17-160c1. The hole intersected basement lithologies beginning at 96.5 m which consisted of semi-pelitic gneiss and orthogneiss of variable composition. Several broad deformation zones were encountered throughout. Extensive zones of hydrothermal alteration were also intersected which generally consisted of replacement- and hydrothermal breccia-style clay, chlorite and silicification. The hole intersected visible disseminated, vein-style, and semi-massive pitchblende mineralization in close association with deformation and hydrothermal alteration. A total composite mineralization of 7.5 m including 0.5 m of off-scale radioactivity (>10,000 to >61,000 cps) was intersected within a 19.0 m section (134.5 to 153.5 m) before the hole was terminated at 345.0 m.

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 prospective uranium exploration assets in the Athabasca Basin, Saskatchewan, Canada, including a 100% interest in Rook I, location of the Arrow Deposit in February 2014, the Bow discovery in March 2015, the Harpoon discovery in August 2016 and the South Arrow discovery in July 2017. The Arrow deposit's updated mineral resource estimate with an effective date of December 20, 2016 was released in March 2017, and comprised 179.5 M lbs U3O8 contained in 1.18 M tonnes grading 6.88% U3O8 in the Indicated Mineral Resource category and an additional 122.1 M lbs U3O8 contained in 4.25 M tonnes grading 1.30% U3O8 in the Inferred Mineral Resource category.