The Paris Silver project is located upon the Peterlumbo Exploration Licence 6347 which is registered under the wholly owned subsidiary of Investigator Silver Limited (formerly Investigator Resources Ltd), Sunthe Minerals Pty Ltd.
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Summary:
The Paris Silver deposit is interpreted to be hosted within a sequence of flat lying intensely altered, polymictic volcanic breccias related to the Gawler Range Volcanics. Mineralisation is predominantly located in the oxide to transition zones of the host breccia above a palaeo unconformity on a basement of older dolomitic marble. Mineralisation extends for 1,600m of strike length with variable width up to 800m wide. Depth to fresh rock is variable ranging from 60 to 130m below surface. A nominal base to a majority of the drilling is 25mRL, approximately 160m below ground level.
The Paris Ag deposit is likely to have formed at ca. 1594-1590 Ma with S isotopes indicating a dominantly magmatic/mantle source for mineralisation. The magmas associated with the deposit are highly fractionated and consistent with the evolution of a magmatic system to the point where metals (e.g. Silver) could concentrate in the magma and late fluid stages.
The Paris Project has a basal sequence of predominantly dolomitic marbles and calc silicates of Hutchinson Group age, although interpreted faulted sequences of graphitic metasediments, banded iron formation and biotite/chlorite schists are also observed within the margins of the deposit and are interpreted to be of similar age. The upper dolomite surface is interpreted to be a paleo-unconformity, evidenced by development of an iron rich, limonitic cap in many areas and an association with Coronadite (Pb(Mn4+6Mn3+2)O16) a lead oxide mineral.
Overlying this basement sequence is an interpreted blanket of intensely argillic altered Gawler Range Volcanics possibly maar related. Whilst primary features can be displayed within this sequence there has been extensive and pervasive alteration and as such, supportive petrology and structural data has limitations.
Units identified within the altered volcanics include polymictic volcanic breccias, monomict breccias, cross cutting felsic dykes (in some instances peperitic) and layered and flow banded volcanics.
A series of narrow dyke like granitoid intrusives are present which intrude the Hutchinson Suite basement lithologies. These intrusives are interpreted to be of Hiltaba age and some evidence is present to support a co magmatic emplacement with the Gawler Range Volcanics. The emplacement of these dykes is presumed to be focussed on brittle fracturing and faulting of the basal dolomites which likely focussed hydrothermal fluid flow within the deposit.
Deposit Type
The deposit is interpreted to be formed in an intermediate sulphidation epithermal setting and has likely been exposed to multiple mineralising phases. The intense alteration of the deposit makes interpretation of genesis difficult, with current models including a breccia/maar type system or structurally constrained system.
Alteration within the deposit is intense, with tertiary weathering only interpreted to be to a depth of circa 14m over the deposit. Dominant alteration gangue minerals include kaolin, illite and minor talc proximal to the dolomite basement. Intense silica alteration has occurred within the deposit.
The majority of mineralization is interpreted to be strongly structurally controlled and potentially, with hydrothermal fluid presumed from a more distal possible porphyry system as a source to mineralisation. An alternate, purely structurally controlled model for brecciation and mineralisation has also been modelled and considered. Both models considered do not impact on the gross distribution and geometry of mineralisation that has been modelled and estimated.
Sporadic carbonate replacement style mineralization is present within the dolomitic marble and calc silicate basement units underlying the Paris Project. A dominant component to mineralisation is related to flat lying breccia material, whilst a lesser component is constrained to steeply dipping, narrow faults that are sub parallel to the long axis of the deposit.
Mineralisation
Within the basement, below the Gawler Range Volcanics, minor massive sulphide mineralization in the form of pyrite/sphalerite/galena is present in irregularly sized and distributed locations within the dolomitic marbles. This is primarily related to carbonate replacement and brittle fracture fill.
The dominant polymictic breccia host has variable sized clasts, some of which contain sulphides, in addition to matrix sulphide mineralisation. These clasts have a similar sulphide content to that observed within the limited massive sulphide observed within the upper reaches of the dolomitic marble (dominantly pyrite/sphalerite/galena). Clast sizes are variable in size from a few millimetres to tens of centimetres however the average size distribution is approximately 5mm to 10cm.
A syn to late mineralizing event at Paris appears to have been a pyrite dominant phase which resulted in the deposition of fine sulphides within the matrix of the volcanics at Paris. There are zones of significant pyrite mineralisation, particularly within the base of the layered polymictic breccia, where semi massive pyrite and disseminated pyrite are more common.
There is also evidence of late-stage metal dispersion and zones of potential supergene enrichment within the Paris Silver Project.
Silver Mineralisation
The silver mineralisation has been characterised and identified silver is hosted in several forms with the dominant forms being native silver and/or acanthite (AgS) with quartz. Other lesser forms identified include silver with jalpaite (CuAgS2), chloraryrite (AgCl), with pyrite as argentopyrite (FeAgS). The relative proportions of the silver host minerals vary throughout the resource. Silver mineral particles were often identified at sizes that were less than 30 microns (30 millionths of 1m) in size, with a component less than 10 microns. Understanding this size distribution assisted with determining recovery opportunities and processes targeting liberation of silver minerals from their host particles were prioritised.
Dimensions
The main mineralised envelope trends north-south over approxi-mately 2km with an average width of around 400m averaging around 40m thick. It generally lies within the breccia unit and ex-tends only comparatively short distances into the dolomite and metasediment units. The main envelope was subdivided into six domains of comparable of silver mineralisation tenor. The back-ground domain trends north-south over approximately 2km, encap-sulating the main mineralised envelope with an average width of around 530m and reaches a maximum depth of around 240m.
Mineral Resources are constrained above OmRL which approxi-mates a depth of 175m below surface and represents Investigator's interpretation of estimates with reasonable prospects of eventual economic extraction.