The Big Red Project, Fraser Range
E28/2322 - Granted - RTR Owns 100%
E69/3190 - Granted - RTR owns 100%
The Big Red Project is prospective for sulphide Nickel and Copper mineralisation similar to the discovery of the Nova deposit almost two years ago by Sirius Resources Ltd (ASX: SIR).
Ground EM Survey
Rumble completed a moving-loop Electro-magnetic (EM) survey to explore the highly prospective magnetic and gravity targets within Rumbles Big Red project. The target areas were recently identified through reprocessing of ground gravity data and 3D inversion modelling of detailed airborne magnetics. Processing of the data identified a significant bedrock conductor which is over 2km long. This very large bedrock conductor is of moderate conductance levels, commences at a depth of approximately 250m and dips to the East.
The conductive body is parallel to the local geology and the conductance levels are also increasing and becoming shallower to the north. It is also a magnetic high which is significant as pyrrhotite, the main constituent sulphide mineral of Nickel deposits, can be magnetic mineral.
The exciting geological factors previously defined in the project area were the result of drilling completed by Teck Australia in 2010 and subsequent study on the drill core by the Geological Survey of Western Australia. This included the intersection of mafic gabbro sills in both Teck Australia drill holes. BRDDH001 & BRDDH002, which is also the host rock unit to the Nova and Bollinger nickel-copper sulphide deposits and interestingly also the host to nickel-copper sulphides intersected at the Mammoth target by Classic Minerals Ltd (ASX:CLZ) announced in December 2013.
Age dating of drill core returned crystallization ages of around 1.3 billion years which are consistent with age dates from within the Fraser Zone close to the Nova-Bollinger deposits. Hyperspectral logging (HyLogger) data from both Teck Australia drill holes has recently been received and will provide valuable data on the local geology adjacent to the conductive body.
Figure 1 Detailed Magnetics with Ground EM
Detailed Airborne Magnetic Survey
A detailed airborne magnetic survey was completed in September 2014.
The 3D inversion results highlight a large area that is both conductive and magnetic and for the first time highlight a relationship with the large gravity body located adjacent to it. It is north plunging and is coincident with the 2.2 km conductor which is one of the largest in the Fraser Range. This 3D modelling is shown as a plan view and also a view looking North in Figures 2 and 3.
The area of both high magnetics and moderate conductance represents a possible feeder zone to a larger body outlined by the large 6km gravity body located to the northwest which is interpreted as a large magma chamber. Feeder zones are important as they can contain significant amounts of nickel and copper sulphides for example the Ovoid deposit at Voisey’s Bay in Canada. The magnetic response may be due to the presence of magmatic magnetite
Maiden Drill Program
A maiden drill program was completed in the December quarter consisting of 4 Mud Rotary/Diamond drill holes totalling 1,503.9m with the programme designed to test a 2km EM conductor outlined by a high powered ground EM survey
Rumble received all assays from its maiden drill program with the assays confirming all three holes intersected large disseminated mineralised sulphide zones within gabbros of the Fraser Range Complex. These sulphide zones are of considerable widths and indicate this large conductor to be a significant mineralised system. Intersecting Fraser Range gabbro is of significance as it is the rock unit which can host magmatic Ni-Cu sulphide deposits.
Detailed petrographic analysis of samples collected from the diamond drilling program confirmed the presence of magmatic sulphides. Nickel (pentlandite) and Copper (chalcopyrite) sulphides in association with pyrrhotite and magnetite are present within Fraser Range gabbro.
Following the drilling Rumble completed a Downhole EM Program which identified 2 very high conductance off hole conductors of 6000 to 8000 siemens which can be typical of massive sulphide accumulations. It is noted that the petrology did not indicate any conductive units within the lower portion of hole BRDD003. Hole BRDD002, which is located 400m to the south, contains the mineralogy present in magmatic nickel copper feeder systems with sulphides of pyrrhotite, chalcopyrite pentlandite and also magnetite. This now makes these off hole conductors first order targets in the company’s exploration of the Fraser Range.