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Pitchblende vein from NexGen drill hole RK-14-27 at 250m.

NexGen Setting the Bar High for PLS Neighbours

With NexGen’s recent results looming large, other companies looking for uranium in and around the PLS project are suddenly feeling a lot of pressure to have similar successful drill results.

Disclaimer: This is an editorial review of a public press release and not an endorsement. It may include opinions or points of view that may not be shared by the companies mentioned in the release. The editorial comments are highlighted so as to be easily separated from the release text and portions of the release not affecting this review may be deleted.

VANCOUVER, BRITISH COLUMBIA–(Marketwired – March 13, 2014) – NexGen Energy Ltd. (TSX VENTURE:NXE) (“NexGen” or the “Company”) is pleased to announce the discovery of further new zones of uranium mineralisation within a second hole (RK-14-27) in the Arrow prospect, Rook 1 project in the SW Athabasca Basin, extending the known zone of uranium mineralisation down dip and along strike.

The first hole at Arrow, RK-14-21 (as previously reported on Sedar, February 24, 2014), was completed at 663.0m. It intersected uranium-mineralised brecciated structural zones over several zones downhole, including 26.2m from 204.8-231.0m, 0.6m from 318.5-319.1m, 26.8m from 517.9-544.5m, and 4.0m from 580.0-584.0m. Four further holes have been completed at Arrow (holes RK-14-24, -25, -26, and -27).

NexGen’s Arrow prospect is part of their Rook 1 uranium project located just to the northeast of the Fission’s PLS (Patterson Lake South). Intersections of high grade uranium in multiple zones last month sent their stock soaring from $0.225 to over $0.50 where it still sits. With NexGen’s recent results looming large, other companies looking for uranium in and around the PLS project are suddenly feeling a lot of pressure to have similar successful drill results. We included a map of NexGen’s Athabasca land positions below.

NexGen's land positions are shown in Red on this map of Athabasca Basin uranium properties.

NexGen’s land positions are shown in red on this map of Athabasca Basin uranium properties. Fission’s PLS is in yellow and southwest of Rook 1.

The most recent hole, RK-14-27, was completed to a depth of 576m. It intersected uraniferous structurally-disturbed zones similar to the zones in hole RK-14-21, and interpreted to be continuations of those zones. These include downhole radioactively anomalous intercepts in RK-14-27 of 0.25m from 224.45-224.70m, 15.05m from 240.65-255.70m, 1.25m from 359.20-360.45m, and 0.20m from 435.70-435.90m.

Andrew Browne, NexGen’s Vice-President, Exploration and Development, commented, “The structural interpretation of uranium mineralised zones at Arrow has been validated. We are greatly encouraged by this confirmation of both along strike and down dip extensions, and by the preliminary thickness and strength of the radioactivity. Further drilling at Arrow is designed to continue to confirm the strike and dip extent of this newly discovered uranium mineralised prospect.”

This most recent drilling was designed to look for continuity in the mineralized zones encountered in other drilling. As more drill results come in, a picture of the subsurface structure will form. This will be used, along with other data such as geophysical and radiometric data to develop a picture of the mineralized system.

Leigh Curyer, NexGen’s CEO commented, “Andrew Browne, James Sykes and Matthew Schwab (the core NexGen technical team) have done a terrific job in only the 5 holes drilled to date at Arrow. The arrival of a third drill rig for the summer program will significantly expedite the results and potential of Arrow and the other identified geophysical targets on the western section of Rook I.”

As previously reported, the Arrow zone is structurally complex, with a range of basement lithologies having variable competency contrast. Hole 21 suffered a deviation from its planned trace apparently due to a combination of boulders in the glacial overburden and foliated basement. Holes RK-14-24, -25, and -26 were planned and drilled to ascertain the orientation of the dominant mineralised structures. While no major radiometric zones were intersected, analysis of structures in these holes meant that hole -27 was successfully planned to intersect the interpreted mineralised zones both along strike and down dip. The next follow up hole, RK-14-29, is planned a further 40m SW along strike to again intersect the interpreted mineralised Arrow zones.

The company is telling us that holes 24, 25 and 26 did not encounter significant mineralization, but allowed them to better develop their target for hole 27. This is fairly typical in early exploration. While companies can rarely get lucky and hit something significant on every hole, more often their step-out holes help them with target refinement by showing them what’s not there and helping the geologist better understand the subsurface geology.

Hole RK-14-27 has been probed radiometrically, using a Mt Sopris 2PGA-1000 total count natural gamma scintillometer probe (Fig 4). The significant radioactive zones have been measured using a hand-held Radiation Solutions Inc RS-125 spectrometer (Table 1), and this has confirmed that all radiometric activity is due to uranium. Currently, NexGen defines “significant” as a minimum of 5cm greater than 500 cps (counts per second). Note that the Radiation Solutions RS-125 spectrometer now used for core scanning is a different instrument to the Exploranium GR-110 previously used. The RS-125 spectrometer has a larger detector crystal than the Exploranium GR-110, but the total count gamma scan readings in counts per second (cps) are in the same range and it is used for qualitative indications of radioactive anomalism.

As in hole RK-14-21, the host lithology throughout most of hole RK-14-27 comprises variably chloritised medium/coarse-grained quartz-garnet-feldspar gneiss, with localized graphitic zones, shearing, brecciation, minor silicification, local dravitic clay veins, and clay alteration. All mineralised zones are being sampled for chemical analysis.

Hole RK-14-28 is in progress, and is designed to intersect the cause of the gravity low at Arrow.

The map below shows the drill hole locations over the gravity survey of the area. Gravity surveys identify density contrasts in the subsurface and help identify subsurface structural features or lithology (rock type) changes. NexGen is drilling hole RK-14-28 in the center of a gravity low, while other holes are designed to intersect the known mineralized zones. Note that even though this is a top view of the map, the drill holes are shown as lines on the map representing the horizontal extent of the drill holes which are drilled at angles from the surface.

NexGen Arrow Prospect planned and previous drill hole locations as shown on their gravity survey map.

NexGen Arrow Prospect planned and previous drill hole locations as shown on their gravity survey map.

What you’ll notice from the drill results below is that the results are not assays, but measurements of radioactivity from a handheld radiation detector. They’ve indicated in the table footer that any value less than 500 cps is considered “anomalous”, but this is a typo. What they mean to say is that any value greater than 500 cps is “anomalous”.

Values greater than 10,000 (off scale) would be expected in a zone containing veins or masses of visible pitchblende like that shown in the core image above. Pitchblende is a black uranium-rich ore mixture primarily containing the mineral uraninite (UO2).

Table 1 Radioactively anomalous zones in RK-14-27
Hole From
(m)
To
(m)
Interval
(m
downhole)
Min
cps
Max
cps
Comments
RK-14-27 224.45 224.70 0.25 less than 500 600 0.25
RK-14-27 239.45 239.70 0.25 less than 500 600 0.25
RK-14-27 240.65 241.00 0.35 800 1000 2.35
RK-14-27 241.00 241.20 0.20 1000 2500
RK-14-27 241.20 241.55 0.35 less than 500 1000
RK-14-27 241.55 241.70 0.15 1000 1300
RK-14-27 241.70 242.00 0.30 less than 500 1000
RK-14-27 242.00 242.10 0.10 1400 1700
RK-14-27 242.10 242.30 0.20 1800 2400
RK-14-27 242.30 242.40 0.10 1100 1300
RK-14-27 242.40 242.55 0.15 1800 2000
RK-14-27 242.55 242.70 0.15 3000 3500
RK-14-27 242.70 242.85 0.15 550 650
RK-14-27 242.85 243.00 0.15 less than 500 550
RK-14-27 243.00 243.30 0.30 less than 500
RK-14-27 243.30 243.40 0.10 less than 500 700 12.4
RK-14-27 243.40 243.75 0.35 less than 500 600
RK-14-27 243.75 243.85 0.10 600 700
RK-14-27 243.85 244.05 0.20 750 850
RK-14-27 244.05 244.20 0.15 1250 1500
RK-14-27 244.20 244.35 0.15 6100 greater than
10,000
RK-14-27 244.35 244.50 0.15 greater than
10,000
greater than
10,000
RK-14-27 244.50 244.60 0.10 1700 2600
RK-14-27 244.60 244.80 0.20 1500 2100
RK-14-27 244.80 244.95 0.15 2200 3200
RK-14-27 244.95 245.15 0.20 3000 4500
RK-14-27 245.15 245.40 0.25 5500 7000
RK-14-27 245.40 245.50 0.10 4000 4500
RK-14-27 245.50 245.55 0.05 950 1200
RK-14-27 245.55 245.65 0.10 850 950
RK-14-27 245.65 245.95 0.30 1500 1800
RK-14-27 245.95 246.00 0.05 1000 1200
RK-14-27 246.00 246.20 0.20 2200 3000
RK-14-27 246.20 246.40 0.20 1100 1300
RK-14-27 246.40 246.55 0.15 800 1000
RK-14-27 246.55 246.85 0.30 500 850
RK-14-27 246.85 246.95 0.10 1000 1350
RK-14-27 246.95 247.15 0.20 1700 2000
RK-14-27 247.15 247.30 0.15 3500 4500
RK-14-27 247.30 247.50 0.20 6000 7000
RK-14-27 247.50 247.90 0.40 8000 greater than
10,000
RK-14-27 247.90 248.10 0.20 2500 4000
RK-14-27 248.10 248.30 0.20 3000 4200
RK-14-27 248.30 248.65 0.35 2500 3600
RK-14-27 248.65 248.85 0.20 9000 greater than
10,000
RK-14-27 248.85 249.00 0.15 greater than
10,000
greater than
10,000
RK-14-27 249.00 249.20 0.20 1000 1300
RK-14-27 249.20 249.35 0.15 1400 1800
RK-14-27 249.35 249.45 0.10 4000 5000
RK-14-27 249.45 249.65 0.20 5500 8000
RK-14-27 249.65 249.75 0.10 3700 5200
RK-14-27 249.75 249.85 0.10 5500 9000
RK-14-27 249.85 250.05 0.20 greater than
10,000
greater than
10,000
RK-14-27 250.05 250.25 0.20 greater than
10,000
greater than
10,000
RK-14-27 250.25 250.35 0.10 900 1000
RK-14-27 250.35 250.65 0.30 1300 2000
RK-14-27 250.65 250.70 0.05 1000 1150
RK-14-27 250.70 250.85 0.15 850 1000
RK-14-27 250.85 250.95 0.10 700 750
RK-14-27 250.95 251.25 0.30 550 700
RK-14-27 251.25 251.55 0.30 800 1100
RK-14-27 251.55 251.65 0.10 2000 3000
RK-14-27 251.65 251.80 0.15 2500 4000
RK-14-27 251.80 252.00 0.20 greater than
10,000
greater than
10,000
RK-14-27 252.00 252.40 0.40 7000 greater than
10,000
RK-14-27 252.40 252.50 0.10 greater than
10,000
greater than
10,000
RK-14-27 252.50 252.65 0.15 greater than
10,000
greater than
10,000
RK-14-27 252.65 252.95 0.30 7000 greater than
10,000
RK-14-27 252.95 253.15 0.20 4000 8000
RK-14-27 253.15 253.30 0.15 8000 greater than 10,000
RK-14-27 253.30 253.40 0.10 greater than
10,000
greater than
10,000
RK-14-27 253.40 253.50 0.10 greater than
10,000
greater than
10,000
RK-14-27 253.50 253.95 0.45 greater than
10,000
greater than
10,000
RK-14-27 253.95 254.05 0.10 800 1200
RK-14-27 254.05 254.15 0.10 greater than
10,000
greater than
10,000
RK-14-27 254.15 254.25 0.10 greater than
10,000
greater than
10,000
RK-14-27 254.25 254.35 0.10 4000 5000
RK-14-27 254.35 254.50 0.15 7500 greater than
10,000
RK-14-27 254.50 254.70 0.20 2100 3600
RK-14-27 254.70 254.85 0.15 800 1200
RK-14-27 254.85 255.00 0.15 600 750
RK-14-27 255.00 255.70 0.70 less than 500 550
RK-14-27 260.40 260.55 0.15 less than 500 650 0.15
RK-14-27 359.20 359.55 0.35 less than 500 600 0.35
RK-14-27 359.55 360.00 0.45 less than 500
RK-14-27 360.00 360.45 0.45 550 800 0.45
RK-14-27 435.70 435.90 0.20 600 700 0.2
* “Anomalous” means min 5cm at less than 500 cps (counts per second)
** Total count gamma readings by gamma spectrometer type RS-125

 

Natural gamma radiation in drill core reported in this news release was measured in counts per second (cps) using a Radiation Solutions Inc RS-125 gamma-ray spectrometer, and a Mt Sopris 2PGA-1000 natural gamma probe. The reader is cautioned that total count gamma readings may not be directly or uniformly related to uranium grades of the rock sample measured; they should be used only as a preliminary indication of the presence of radioactive minerals. All intersections are downhole. Core interval measurements and true thicknesses are yet to be determined.

We mentioned this earlier, but take note of the company’s disclaimer in bold. These results are not assays, but indications of radioactivity. True assay will likely follow as they become available. Also note that the reported widths are the “apparent thicknesses” measured along the drill core length and not true thicknesses.

Qualified Person

Andrew Browne, FAusIMM(CP), NexGen’s Vice President, Exploration & Development, is a “qualified person” for the purposes of National Instrument 43-101 – Standards of Disclosure for Mineral Projects, and has reviewed and approved the contents of this news release.

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 exploration professionals with a track record in the discovery of unconformity-style uranium deposits in Canada.

NexGen owns a portfolio of highly prospective uranium exploration assets in the Athabasca Basin, Saskatchewan, Canada, including, an option to earn a 70% interest in the Radio Project, immediately adjacent to Rio Tinto’s Roughrider Deposit and a 100% interest in Rook 1, immediately adjacent to the north east of Patterson Lake South.

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Geology for Investors seeks to demystify mineral exploration and mining projects for mining company investors. All of our writers and contributors are experienced and educated in geology and the geosciences.