The Riou Lake property consists of two claims AC00000267 and AC00000312 covering 6,200 hectares (approximately 15,300 acres) located in the Athabasca basin of northern Saskatchewan. The claims were staked adjacent to the Riou Lake Uranium project operated by UEX Corp. In 1996 Pioneer Metals (now UEX) staked around the claims looking for nickel. In 2001 UEX was formed with a 40% Cameco (world’s largest uranium producer) ownership.
The claim encompasses the western extension of the Riou Lake fault system. Seven creeks originating from the escarpment were sampled and found to contain elevated amounts of pathfinder minerals. The sampling of this area was originally done by Dr. J. G. Strnad who recommended staking the Riou Lake escarpment and surrounding area.
The escarpment is unique in the Athabasca basin and is displaced 180 feet above the surface and extends on surface for 8 kilometres. The average elevation in the area is approximately 350 meters above sea level.
There is potential of a possible unconformity type uranium deposit or deposits on the Riou Lake property.
Seagrove Capital Corporation contracted Goldak Airborne Surveys of Saskatoon, Saskatchewan to do the first preliminary investigation of the escarpment.
The Athabasca basin hosts several major uranium deposits including Cigar Lake and McArthur River, two of the highest-grade uranium deposits in the world. It is the most productive uranium producing region globally, accounting for approximately one third of the world's supply.
Fugro Airborne Survey provided a deep-penetrating, airborne electromagnetic MegaTEM survey, provided blanket coverage for the entire Riou Lake property. Condor Consulting Inc. of Lakewood Colorado provided a detailed interpretation of the MegaTem survey completed on the Riou Lake project.
The survey detected several zones of anomalous conductivity within the sandstones as much as 600 meters below surface and probably extend deeper. These EM responses could represent alteration zones in the sandstone above uranium deposits concentrated on the unconformity.
The magnetic data supports the interpretation of three major faults.
- One is represented on surface by a prominent escarpment; a vertical offset of conductive layers in the sandstone suggest that this structure displaces the sandstone strata and hence the unconformity by about 100 meters vertically thus creating a favorable trap for mineralizing solutions.
- A second interpreted fault lays parallel to and 3.5 km north of the escarpment fault.
- A third fault trends north-south near the west boundary of the property and intersects the above-described faults.
The two strongest deeper zones of conductivity in the sandstone, designated “A” and “B” on the lie adjacent to one of the above-described faults which enhances their favourability as drill targets.
A detailed sampling program of the abundant sandstone outcrop along the escarpment fault outlined several positive indicators for uranium. The survey indicates positive alteration features typical of those found above uranium deposits, the fault on and above the unconformity is therefore a prime drilling target.
Two areas in particular were targeted:
- The first an eight-kilometer-long section of a prominent escarpment believed to represent a major fault offsetting the Athabasca formations. Outcrop is plentiful along this feature for bedrock sampling. Lines of soil and rock sampling were perpendicular to this structure.
- The second target area is over “Anomaly A”, a zone of low resistivity in the sandstone interpreted from the airborne MegaTem survey which could represent an alteration halo over mineralization on the unconformity below it.
Conventional atomic absorption analytical techniques were used to assay the surface samples. Also a relatively new method which testing for minute quantities of Soil Gas Hydrocarbons (SGH) has shown promise in the detection of deposits at greater depths than with conventional techniques will be used.
All samples were submitted to the Saskatchewan Research Council (SRC) and Activation Labs in Ontario for analysis. Activation Laboratories (Act Labs) located in Ancaster, Ontario, provided an interpretation of the Soil Gas Hydrocarbon (SGH) analyses on a grid of soil samples collected.
Soil samples have been analyzed by both conventional ICP and a relatively new method which measures minute traces of Soil Gas Hydrocarbons (SGH). The latter method has promise of detecting evidence of mineralization from greater depths than conventional techniques.
Samples from the Main Grid ,which were taken along the previously identified 8 km long escarpment fault (the escarpment is 8 km and the fault can be traced 12km) produced two strongly anomalous areas which Act Labs believe indicate a” Very High Probability” of a Uranium target at depth. This is the highest level of detection possible under the SGH Rating System under which there are 6 categories ranging from a “Low Probability” rating to a “Very High Probability” rating. A “Very High Probability” rating means that the SGH classes most important to describing a Uranium signature are all present and consistently describe the same location with well-defined anomalies. To obtain this rating there also needs to be other SGH
classes that when mapped lend support to the prediction location.
The three primary Uranium indicator classes resulted in apical style anomalies in two areas of the main grid. These areas replicated exceptionally well across the three SGH indicator classes which means that the interpretation at this site was very definitive. Thus, due to the agreement across the SGH Uranium indicator classes, there is a “Very High Probability” of Uranium targets at the Primary and Secondary target areas shown at the main grid. The Secondary target is only slightly less in quality of agreement and may actually have the same characteristics as the Primary Uranium target area. In this interpretation, the best drill targets are most likely to coincide with the centre of the high SGH anomaly areas within the Primary and Secondary target zones.
The two anomalies lie along the Escarpment Fault where it is intersected by north-south faults interpreted from the airborne MegaTem time domain electromagnetic and magnetic survey flown by Fugro Airborne Surveys and further analyzed by Condor Consulting Ltd. The centers of the two anomalies lie approximately 5 km apart and constitute two separate target areas. The Primary Target Area is 3 km long and the Secondary Target Area is 2 km long.
The eastern anomaly (The Primary Target) also coincides with a possible zone of alteration suggested by a magnetic low along the Escarpment Fault and one sample from a stream exiting the escarpment yielding 9.4 ug/L (micrograms per litre) of U which is anomalous. Four other water samples taken from other locations on the property had average values of less than 0.1 ug/L.
The targets tested lie where the intersection of faults believed to displace the Athabasca sandstone coincide with strong soil gas hydrocarbon (SGH) geochemical anomalies. The SGH anomalies were interpreted by Activation Laboratories Ltd. of Ancaster, Ontario. The two main areas of interest were designated the Prime Target Area and the Secondary Target Area on the Main Grid. Activation’s report states, “There is a very high probability of uranium targets at the primary and secondary target areas shown at the main grid”.
excerpts from a report by:
TECHNICAL REPORT ON A FIXED WING
AEROMAGNETIC AND VLF SURVEY AT
RIOU LAKE, SASKATCHEWAN for
SEAGROVE CAPITAL CORPORATION by
GOLDAK EXPLORATION TECHNOLOGY LTD.
excerpts from a report by:
SASKATCHEWAN MINERAL CLAIMS S-102151 TO S-1 02154 INCL
ASSESSMENT WORK REPORT ON AN AIRBORNE MAGNETIC AND VLF SURVEY
By N. Ralph Newson, M.Sc., P. Eng.
For TREK PROPRIETARY CO.
July 22, 1996
The property is immediately underlain by undeformed and unmetamorphosed sandstone of the Athabasca Basin, which is of late Proterozoic age. These are approximately 300m thick in this area, and overlie crystalline basement of early Proterozoic to Archean age. Comparison of the geology of the exposed part of the crystalline basement with the government aeromagnetic maps makes it clear that the basement underlying the property is part of the Tantato Domain, or as it has recently been called by Hanmer et al (1991 al, the East Athabasca Mylonite Zone.
The East Athabasca Mylonite Zone is a triangular-shaped part of the Snowbird tectonic zone, a subdivision of the Rae Province, and is characterized by a complex structural pattern resulting from polyphase deformations under high-grade metamorphic conditions. It may be one of several crustal-scale "boudins". Various mylonite zones, gneisses and granitic intrusives are present, as are norite, anorthosite and gabbroic rocks, mostly highly deformed. For more detailed descriptions and distribution of the rocks which outcrop in the exposed part of the Mylonite Zone, and which may therefore underlie the property, the reader is referred to Hanmer et al 1991 a, 1991 b, Gilboy, 1980, and Slimmon, 1989.
A prominent scarp in the sandstone strikes east-southeasterly, and likely defines a fault. This scarp is unique in the Athabasca basin, even though it is known from work on uranium deposits that there are other faults through the sandstone, which are likely produced by continued activity on faults in the basement. Also unique in the region is the fact that the scarp is the locus discharge of water carrying extremely anomalous concentrations of limonite. The regional gravity survey shows a gravity low coinciding closely with the scarp.
No bedrock mineralization is known on the property. Nickel-copper mineralization has been found at Axis Lake, in the exposed part of the Mylonite Zone north of the present property, and gold-pyrite mineralization has been found at the Pine Channel narrows, and elsewhere. Economic uranium mineralization occurs at Uranium City, as do lesser concentrations of gold and platinum. Economic deposits of uranium, which also contain significant amounts of base metals, including nickel, cobalt, and copper, occur south of the property.
4.0 MAGNETIC SURVEY
Because the property is so narrow, the necessary turn-around loops extended the coverage some distance off the property. This is fortunate, because it helps considerably in interpreting the results.
A comparison of the results of the survey discussed herein with the available government aeromagnetic survey indicates that the magnetic response is due entirely to the response from metamorphic basement rocks, with no discernible response from anything in the sandstone. Although no quantitative depth-tobasement calculations have been provided, it is clear that the results of the present low-level survey are very little different from those of the high-level government survey, in terms of over-all pattern and gradient. This means that, in percentage terms, the low-level survey is not very much closer to the source than is the high level survey, which means that the source was far away from both sensors, i.e. it was deep. This is confirmed by a comparison of the total field and calculated gradient for the present survey. Again, the patterns are not too dissimilar, which qualitatively indicates a deep source. A few features on the vertical derivative map may not be due to sources quite as deep as the general picture, notably the two areas suggested below as possible drill targets at 415,050E, 6,544,915N, and 415,845E, 6,544,750N. (The coordinates used in the survey, and reported here, are the same as those of the UTM grid which covers the area.)
5.0 VLF SURVEY
The field strength results of the VLF survey show a weak response coincident with the scarp in the sandstone, and a weaker response parallel to the main one. This response is likely due to iron oxide-bearing water percolating up the fault which is suggested to be the cause of the scarp. The parallel response would then appear to be due to a parallel, less prominent, fault. The quadrature response does not appear to correlate with or add anything to the geologic picture.
Two phenomena-the prominent scarp and the large amount of iron oxide being discharged from the ground at the scarp-indicate that there is something very different about this particular spot as compared with any other place in the Athabasca Basin. If the scarp is indeed caused by a fault, then it is part of a very important family of faults, since many of the uranium deposits in the Athabasca Basin are located where faults having this strike intersect other basement structures. Evidence that this fault may contain mineralization is seen in the gravity low that coincides with it. In at least three major uranium deposits where gravity surveys have been done, gravity lows coincide with the alteration halos around uranium deposits at the unconformity between the sandstone and the metamorphic basement rocks.
The heavy discharge of limonite is a further indication of mineralization. The writer has not visited the property, but from photographs of streams and seeps near the scarp it is clear that the concentration of limonite in the water is very high, and is as great, for example, as in water percolating through a sulphidic tailings pond.
If the suggested mineralization is magnetic, then the results of the present airborne survey would seem to indicate that it is likely fairly deep. If it is conductive, it is too deep to be detected with VLF.
What, then might be the nature of any mineralization that may be present? It is clear that it must contain iron that is easily oxidizable. Since the nearby uranium mines contain some base metals, and in fact very high local concentrations of them, it must be concluded that the same processes that produced the uranium deposits also can concentrate base metals. All evidence is that the area does not show a particularly anomalous level of radioactivity. A number of geologic situations can be proposed to account for the observed facts, and it is suggested that one of these is a metallic sulphide deposit at the unconformity. Besides iron sulphides, base metal sulphides could be present. Nickel is the base metal that first comes to mind, since it is present in high concentrations locally is some deposits (up to 45% Ni was reported in the Gartner ore body at Key Lake in the early drilling). A base metal deposit at the unconformity would be consistent with the magnetic results, and not inconsistent with the VLF results. Given this possibility, it is worthwhile to do follow-up work on the property.
The first phase of follow-up work should be a prospecting program, to sample the limonitic sludge flowing from the fault zone, the purpose of which is to determine whether or not the sludge also contains valuable metals. The prospectors should carry scintillometers to detect any radioactivity, although any uranium carried in solution will not be in equilibrium with its daughter elements, and scintillometers will not detect this uranium. Thus, the detection of radioactivity will mean that radiogenic isotopes are present, but absence of radioactivity will not mean that there are no radiogenic isotopes present.
Drilling should follow, and the most appropriate target would appear to be the a small area of high magnetic gradient near the eastern end of the group, at 415,050E,6,544,750N. The highest contours have a long axis parallel to the axis of the gravity low, parallel to the strike direction of the suggested fault, and parallel to the general trend of the VLF anomaly. If there is anything magnetic in the proposed fault, then this is likely it. If this hole intersects mineralization, then the small peak at 415,845E, 6,544,750N becomes a target, as do the magnetic highs both north and south of it, off the property. It would obviously be imperative to stake that ground if the initial drilling results are positive.
A second target area might be at about 410,500E, 6,545,600N, where there is a break in the VLF anomaly, and a roundish, slight high in the vertical magnetic gradient, which may indicate a cross-fault.
All of the initial holes should be vertical, and should be collared directly over the targets, in order to avoid missing the source because of incorrect assumptions as to dip, and depth to the targets.
All of the holes drilled should be surveyed with a down-hole EM system, in order to detect any massive sulphides at depth. It is likely that massive sulphides, if they are present at or below the unconformity, would not respond to surface EM techniques, and therefore no opportunity should be missed to test for their presence close to the drill holes at depth.
7.0 CONCLUSIONS AND RECOMMENDATIONS
1 . The airborne VLF survey has detected a response which may be due to mineralized water percolating through a fault. The aeromagnetic survey appears to have responded mainly to features in the metamorphic basement.
2. When combined with other geological and geophysical features, which indicate the possible presence of mineralization, the present survey provides drill targets to test for such mineralization.
3. Initial drill holes should be vertical. All drill holes should be surveyed with down-hole EM.
4. If initial results of the proposed program are encouraging, additional ground should be staked around the present claim group.
excerpts from a report by:
RIOU LAKE PROPERTY
RIOU LAKE, SASKATCHEWAN
NTS SHEETS 74 -0 -1 and 74 -0 -2
CLAIM NUMBERS: S -102151, S -102152, S -102153 and S -102154
GROUPING CERTIFICATE NO. 45198
2002 EXPLORATION PROGRAM
RIO GRANDE MINES INC.
1996: Seagrove Capital Corporation carries out an airborne magnetic and VLF -EM survey over the property.
1969: Amerada Petroleum Corp. carries out an airborne radiometric survey over an area that includes the present property.
1965: The Saskatchewan Department of Mineral Resources carries out a gravity survey in the area that includes the present property.
1959 - 1962: The Saskatchewan Department of Mineral Resources carries out detailed geological mapping programs in the area at a scale of one inch to one mile.
1949: Mawdsley carries out geological mapping in the Pine Channel area.
1936: The Geological Survey of Canada (Alcock) carries out geological mapping in the area at a scale of one inch to four miles.
On March 14,2002 at a depth of 945.0 meters the drilling of DDH RIO -I was terminated before reaching the target due to excessive depth and the limitations of the drill rig. The casing remains in the drill hole and is capped in order to re-enter the hole at a later date and drill it to completion (into the assumed magnetic basement anomaly).
DOH RIO -I to be non-magnetic. Uranium values from ten clay rich samples of sandstone range from 0.16 ppm to 1.95 ppm and nickel values range from 3.3 ppm to 7.7 ppm.
The drill hole has not intersected any magnetic material that can explain the surface magnetic anomaly and as such the drill hole should be continued to a depth that intersects basement rocks that may host mineralization that is the cause of the magnetic anomaly.
The diamond drilling program was initiated to test the airborne magnetic anomaly, with the location confirmed by a ground magnetic survey as a possible reflection of a basement seated copper-nickel mineralized norite plug. DDH RIO -I was drilled to a depth of 948.0 meters and did not reach the basement rocks. The hole was prematurely terminated in Athabasca sandstone before intersecting the basement rocks because the drill rig had reached its ability to extend the depth of the hole any further.
Magnetic susceptibility readings indicate that all of the Athabasca sandstone intersected so far is non-magnetic and as such the cause of the surface magnetic anomaly has not as yet been determined.
I) DDH RIO-I should be extended until the basement rocks have been intersected as the surface magnetic anomaly may be a reflection of a mineralized magnetic basement feature.
2) Establish a grid over the entire property on a 200 meter section line spacing, for ground control of ground geophysical surveys.
3) Carry out a ground VLF survey on the grid to determine if the east-west trending escarpment that occurs on the property is a possible fault in the sandstone that may be due to continued movement on a fault in the basement.
4) If the VLF survey results are favourable, a drill program should be carried out to explore for an unconformity type uranium deposit.
Pioneer Metals Corporation announces winter drilling confirms uranium potential at Riou Lake, geophysics identify land target
VANCOUVER, June 2 /CNW/ - Pioneer Metals Corporation
Pioneer Metals Corporation (''Pioneer'') is pleased to announce the results of the 1999 winter geophysics and drilling program at its Riou Lake Uranium Project, Athabasca Basin, northern Saskatchewan, Canada. Pioneer is operator of the Project. Work was carried out on both the 100% Pioneer-owned Riou Lake claims as well as those (''PM Claims'') optioned to Cameco Corporation. The results of the program were presented to Cameco representatives at Pioneer's offices late May. The program has added significant value to the property because it established the presence of both a structural and a hydrothermal uranium-mineralizing system. Thus, the likelihood of a uranium deposit being discovered at Riou Lake has increased. Cameco's exploration team indicated they were encouraged by the progress and reaffirmed their financial commitment to the Project.
Under the direction of Pioneer's consulting geophysicists and geologists, a twelve-week program of ground geophysics and drilling was carried out this past winter, commencing January 11. Quantec Consulting Inc. collected one hundred and fifty line-kilometres of geophysical data on three separate grids during the first six weeks of the program, mainly on the PM Claims optioned to Cameco. Eight diamond drill holes totaling 4,687 metres were completed by Midwest Drilling Ltd. Seven of the eight holes successfully tested the unconformity, which lies at depths between 500 and 700 metres. The four holes drilled on the PM Claims (RLGD-1, 2, 7 & 8) tested targets identified by
geophysical surveys from both the 1999 and 1998 winter programs. The remaining drill holes are located on the 100% Pioneer-owned Riou Lake claims (RLGD-3, 4, 5 & 6) and were intended to provide geological information.
Drilling has confirmed that the essential elements of the unconformity-type uranium deposit model are found at Riou Lake, specifically that:
1. the basement lithology in the magnetic lows is pelitic;
2. graphitic conductors are present within these pelitic basins;
3. the Riou Lake corridor has undergone considerable post-Athabasca tectonism;
4. hydrothermal alteration has affected the region;
5. conditions are favourable for the preservation of uranium.
1. Prior to Pioneer's drilling at Riou Lake this winter, no drill holes had tested the basement rocks in the Riou Lake corridor. The Riou Lake corridor is characterized by a line of dissected magnetic lows striking in a west-northwesterly direction across the otherwise northeast-trending magnetic anomaly pattern south of Lake Athabasca. Pioneer's geologists and geophysicists had speculated that these were caused by a pelitic basement underlying the Athabasca Group sandstones. A pelitic basement underlies all of the major uranium deposits in the Athabasca Basin. Pioneer's drilling tested a number of these lows and intersected pelite in five of the seven holes that tested basement rocks (RLGD-1, 3, 6, 7 and 8). After conducting a petrographic study of Pioneer's drill holes, Saskatchewan Research Council staff (''SRC''), who have studied most of the uranium deposits in the Athabasca Basin, describe the Riou Lake basement as ''fertile for unconformity-type uranium mineralization''.
2. The ground geophysics program discovered a significant electromagnetic anomaly (the ''KC'' conductor) within a previously unsurveyed magnetic low lying immediately to the south of the uraniferous boulder field at the east end of Riou Lake (the ''W-Zone'', see News Release, Sept. 24, 1998). A new grid, the W-grid, was established to further define this conductor. Interpretation of the EM results from the W-grid by Pioneer's geophysicists, in collaboration with geophysicists from Cameco and Quantec, pinpointed two targets which were subsequently drilled (RLGD-7 & 8). Drilling of hole RLGD-8 proved that the KC conductor is caused by a zone of basement graphite conductors hosted within a mylonitized zone in a pelite basin. The presence of a graphitic basement conductor is thought to be an essential element of the unconformity-type uranium deposit model in the Athabasca Basin. The individual graphite bands grade up to 15% graphite and show evidence of alteration. Pioneer is especially pleased that the conductor is wholly located on land, making it accessible for year-round drilling.
3. The Riou Lake Property, particularly the eastern area, is highly tectonized. Drilling at three drill holes intersected breccia zones in the sandstone (RLGD-1 & 2) and at the unconformity (RLGD-7). The breccia zone at RLGD-7 is associated with a reverse fault structure that offsets the basement by 60 metres, delineating a sandstone wedge similar to those associated with some uranium deposits found in the Wollaston Belt. If all three breccia zones were part of the same structure, it would indicate the presence of a major west-northwest fault system. RLGD-6 proved the presence of a graben in the central Riou Lake area. The graben is a fault-bounded block that has been displaced downward with respect to the neighbouring rocks in excess of 100 metres. The directions of the bounding faults are inferred to trend north-northeast. The presence of two major fault trends at roughly right angles will result in many highly brecciated, ''open'' cross-fault structures on the property. Further study of the area this summer will map and provide targets for drill testing of the fault structures in and around Riou Lake.
Brecciated fault zones provide the plumbing system required for the development of stable hydrothermal focussed flow that carries uranium and associated metals -- the ''hydrothermal system''.
4. Geoscientists from SRC are of the opinion that the strong bleaching and clay alteration in the sandstone observed in RLGD-1, 7 and 8 and the Numac hole (see News Release, September 24, 1998) indicates the presence of a hydrothermal system. These holes are contained within a 6 sq. km area inside the PM claims. Discrete alteration was also recognized in other holes within the sandstone and into the basement, demonstrating the regional extent of the phenomenon. Geochemical analysis of the core shows that there is a strong uranium anomaly at the unconformity under much of the Riou Lake Property. Anomalous uranium was encountered in the seven drill holes that reached the unconformity with values as high as 330 ppm (background equal to 5 ppm). Anomalous uranium (12 ppm over a background of 0.25 ppm) in RLGD-1 associated with anomalous lead, cobalt, nickel, boron and arsenic was also detected in
sandstone fractures as high as 620 m above the unconformity. The vertical extent of these metals is particularly significant in that it shows the strength and magnitude of this hydrothermal plumbing system that has removed these metals from their source and circulated them so close to surface.
5. The pervasive presence of pyrite and siderite in the sandstones throughout the Property confirms that the sandstones in their more recent history did not suffer oxidizing conditions. This would have helped to preserve any uranium mineralization emplaced by the hydrothermal system. In every sense, the winter's exploration effort met and exceeded expectations in that it proved the presence of the essential elements of the unconformity-type uranium deposit model on the Property. Presently, Pioneer's consultants are assessing the last of the geochemical and X-ray analyses of the core from the winter program. In order to provide specific areas of interest for the summer field program, an air photo study and analysis of a reprocessed detailed aeromagnetic survey dating from 1979 are about to begin.
The summer program of reconnaissance and detailed geological mapping, till boulder studies, lake sediment geochemical surveys, and a borehole EM geophysical survey of RLGD-7 will begin in mid-July and continue for four to five weeks.
ON BEHALF OF THE BOARD OF DIRECTORS OF PIONEER METALS CORPORATION