Rockgate Capital Corp. is a TSX Venture listed mineral exploration and development
company focused on advancing its portfolio of uranium/silver and gold projects in West
Africa.
Rockgate's main project is the 100% owned Falea Uranium/Silver deposit located in
southwest Mali. Initially discovered by Cogema (Areva) in the late 1970's, Falea has
been substantially expanded by Rockgate with over 45,000 metres of diamond drilling now
completed in over 175 holes. This work identified a new zone of uranium and high grade
silver and on May 15, 2009, Rockgate released the first independent NI 43-101 resource
calculation for the Falea project reporting a total uncapped resource of 20,252,000
pounds of uranium and 31,600,000 ounces of silver.
Falea Project Location
Located in western Mali, west Africa, approximately 20 kilometers north of the Guinean border, centered on the village of Falea
The property covers an area of 150 square kilometers situated on a relatively flat plateau with scattered low rolling hills and a few shallow rivers
Falea is accessible both by vehicle and by air directly from Bamako. Rockgate has built a 1.6 km airstrip located next to the 20-man camp to meet year-round supply and safety requirements
Regional Geology
The Falea epicontinential and intracratonic basin is typical in age and style of sedimentation of known uranium producing basins and overlays Birrimian stratigraphy that has been intruded by uraninite bearing Saraya granites.
Falea Property Geology
Locally, sedimentation of the Neoproterozoic, Falea Basin was structurally controlled by north-south and east, south-east trending structures. These structural orientations are similar to those occurring during the Birrimian indicating a rejuvenation of the interlocked grabens. On the Falea project area the stratigaphic sequences are up to 300 metres in thickness. The Kania Sequence occurs near the basal unconformity and can be up to 26 metres thick. It is this sequence that the uranium and copper mineralization is situated in.
Alteration and Mineralization
Entire Neoproterozoic Falea sequence varies between reduced and oxidized states. Some oxidization may be diagenetic
Oxidized units and bleached containing clay minerals and sericite with lower portion silicified
Copper oxidation assemblages include covellite and digenite with rare native silver inclusions in digenite
In the periphery of the oxidation, copper mineralization occurs as chalcopyrite, bornite, tennantite and mispickel. Chalcopyrite is dominant and always associated with uraniferous minerals, often rimming the sulphides
Protected from oxidation, the Kania Group black-grey sandstones and shales carry the higher copper content (4.7% Cu DDH-Bodi 4*) as generally uniformly distributed sulphides throughout the sequence. (*All figures taken from historical Cogema reports, NOT to NI 43-101 standards and subject to verification.)
It is in these higher grade copper zones that radiometric responses were most intense at 16,000 counts/second AVP Ra. Therefore, the presence of copper, brecciated or in place stromatolites have a strong relationship to uranium mineralization
Deposition of uranium mineralization appears to occur after the copper mineralization
Uranium mineralization consists of pitchblende and coffinite
Microscopic observations indicate that uranium was carried by oxidizing fluids, thereby being deposited at the REDOX contact in the oxidation of the copper minerals with local crystallization of hematite on the surfaces of the sulphides
Interpretation of Uranium Mineralizing Environment
Observations indicate that favorable conditions characterized by a reducing environment are found principally in the Kania Group where all radiometric anomalies occur
Stromatolites grew in reduced, carbonate rich environment, favorable for sulphide deposition
Oxidant diagenetic uraniferous fluids leach the carbonate cement from the sandstones, alter feldspars to sericite
Sulphides are oxidized in part or totally and sandstones are silicified
Uranium is always found at the REDOX contact
Falea Sedimentary Basin
Three distinct north south trends, 10% of Central zone tested to date by Rockgate
50 holes completed to date and tested the U/Cu-bearing Kania Sequence, majority at 100x100m intervals
Appears to be classic roll front style of uranium mineralization.
Drilling to date has located potentially economic U mineralization over approximate 850x250 metre area (Central Zone)
Central Zone remains open in three directions with higher grade holes near edge of zone.
Central Zone/North Zone and Proposed Program
Completed Drill Holes
Indicates consistent uranium and high grade silver mineralization on North Zone, open in all directions.
Drilling highlights include: DF-168: 0.18 % U3O8, 2,645 g/tonne Silver over 7.0 meters, DF-169: 2.37% (52.14 lb/tonne) U3O8 over 1.00 metres and DF-175: 2.37% (52.14 lb/tonne) U3O8 over 1.00 meter (Discovery is near the edge of Falea plateau and within 200 meters of favorable horizon reaching surface)
NI 43-101 resource estimate from 100% owned Falea, uranium/silver/copper project
The current drilling program has four main objectives:
Define and expand the North zone to the south toward the Central zone. Both the North and Central zones remain open in most directions. The Central zone is approximately two kilometers south of the North zone;
Define and expand the North zone to the north toward the Bodi zone. The Bodi zone is situated approximately 1.6 kilometers north of the North zone;
Test historical drilling by Cogema (Areva) in the Bodi area where uranium mineralization was discovered within 30 meters of surface;
Test numerous downhole radiometric anomalies identified by Cogema located across the Falea licence.
