The Clisbako property is predominantly underlain by a well-differentiated sequence of subaerial, basaltic to rhyolitic tuffs, flows and volcanic breccias of probable Eocene age (Ootsa Lake Group equivalent). Remnants of a younger (Oligocene(?)) rhyolitic ash-flow tuff unconformably overlie the Eocene volcanics in the east-central part of the property and cover a more extensive area immediately south of the property. Flat-lying, red, scoriaceous and black vesicular basaltic flows of Oligocene and Miocene age underlie a relatively broad, flat region extending north and east of the property. Extensive normal (extensional) faulting has affected the Eocene volcanics resulting in an array of variably tilted blocks.
Typically, alteration halos envelope a central zone of siliceous quartz stockwork and breccias within near north trending controlling fault structures. The alteration envelops are dominantly argillic, generally widespread and locally intense. Gold grades are elevated close to the central silicified zone while the argillic envelope is typically barren which may extend up to 150 metres from the central silicified zone.
At least three major hydrothermally altered zones, a number of weaker alteration zones, and extensive areas of quartz float occur within the eastern half of the property. The alteration zones are epithermal in nature and characterized by widespread bleaching and argillic alteration accompanied by a pervasive, moderate to strong stockwork of quartz veinlets and microveinlets. Extensive zones of multistage, intense veining, silicification and brecciation are developed. Very fine-grained pyrite, marcasite and arsenopyrite locally are present in amounts up to 5 per cent. Two hot spring (tufa) deposits are also located on the property.
The three main alteration zones on the Clisbako property are referred to as the North zone (Bucket, Knob and Culvert areas), Central zone and South zone. The Central zone is 500 metres south-southeast of the North zone, and the South zone is 2000 metres south of the North zone. The North and South zones have an apparent true width of 350 to 400 metres; the Central zone is at least 150 metres wide. Two smaller zones referred to as the Trail zone and Discovery zone occur along the projected strike of the South zone, approximately 400 and 1200 metres respectively, to the northeast. Two broad, weaker alteration zones occur along the projected strike of the North zone, centred approximately 1500 and 2000 metres respectively to the southwest. A number of other altered and possible mineralized areas have been identified in outcrop, sub-crop and in boulder float trains on the Clisbako property and include the West Lake (West Lake and West Pit zones) area, the Obvious zone, the West Lake Boulder zone, the Gore zone and the Bari 1 and 2 zones.
On the property, outcrop is sparse and is confined to main gullies and incised drainages; eight lithological units have been mapped. Units 1 to 6 are faulted and variably tilted Eocene volcanics which are unconformably overlain by flat-lying to gently dipping, rhyolitic ash-flow tuffs (unit 8) with a local basal, densely welded, dacitic tuff member (unit 7). Unit 8 overlies lacustrine-type sediments (unit 6). Unit 1 consists of platy, light to medium green, fine-grained andesitic tuffs. The unit appears to be the main host in the Discovery zone, Trail zone, South zone and possibly the North zone. Unit 2 consists of interbedded dark grey dacitic tuff, green andesitic tuff and laminated maroon/purple/green tuff and/or tuffaceous siltstone. Unit 3 is a white to grey, dense, rhyolitic ash-flow tuff with a very finely laminated siliceous matrix; the unit is the principal host in the Central zone. Intensely altered varieties of this unit may also be present in the North zone. Unit 4 comprises medium to dark green, fine-grained, andesitic to basaltic flows. Unit 5 is basaltic in composition, fine grained, dark grey-green flow unit, which may be a member of Unit 4. Unit 6 consists of grey to brown mudstone/siltstone with abundant carbonized plant fossils and appears to be overlain by flat-lying ash-flow tuffs of unit 8. Unit 7 comprises grey, dacitic tuff and is interpreted to be a tightly welded basal member of unit 8. Unit 8 is interpreted to unconformably overlie units 1 to 5 and consists of flat-lying, white to cream-coloured, platy felsic crystal tuffs.
The alteration zones appear to have developed along complex, steeply dipping, north to northeast trending fault structures. Internally, the alteration zones are complex; many appear to be controlled by a series of closely-spaced, subparallel faults rather than a single major structure. The main alteration zones appear to have a long history of development, characterized by episodic periods of strong, resurgent, hydrothermal activity which resulted in several stages of fracturing, brecciation, veining and silicification. Some phases of quartz veining and silicification are sulphide-poor and others are sulphide-rich; pyrite is the main sulphide present, but generally is extremely fine grained and difficult to recognize. Marcasite, arsenopyrite and pyrargyrite have also been identified. In general, better gold-silver values occur in quartz veins which show some banding or in silicified sections which display several stages of brecciation. Carbonate minerals are rare, but coarse bladed carbonate replaced by quartz has been noted in a number of locations.
In most zones, argillic alteration accompanied veining and silicification but as silicification advanced, previously argillic altered units became silicified.
The North zone lies in a down-faulted block of feldspar (+/- quartz) phyric rhyolite flows and tuffs and dacite flows and pyroclastic breccias south of Camp Lake. It is exposed in a gully in which trench excavations have exposed argillic-altered rocks over 300 metres. It has a well-defined east boundary marked by a fault. The west boundary is poorly constrained and is probably continuous with the West Lake Zone. Alteration associated with north-striking faults consists of extensive silicification, quartz and pyrite stockworks, banded epithermal veins and siliceous breccia. Argillic alteration is most pronounced distal from the siliceous zones. Barren quartz stockworks are common in the argillic zone.
The Central (Discovery) zone is a stockwork lying along the same fault structure that hosts the South zone. Quartz-clay alteration is similar to that at the North zone, with extensive quartz stockworks and pervasive argillic alteration occurring in a flow-banded dacite. The zone is narrow and probably connects with the North Zone to the north. In the Discovery area of the Central zone trenches have exposed two narrow breccia zones. The first comprises a 2-metre wide zone of quartz stockworks, white, vuggy quartz veins and hydrothermal breccia. The matrix consists of a bluish-grey clay gouge. The wallrock, which consists of flow banded dacite, is moderately silicified up to four metres away from the breccia. A second less altered breccia consists of black, sulphidic quartz fragments in a moderate to strongly argillized dacite host.
The South Zone is typified by a large area of silicification and hydrothermal breccia. The main outcrop area, in a small creek at the south end of the property, consists of a zone of hydrothermal breccia, veins and stockworks over an outcrop area of 150 metres and has been traced by drilling for some 300 metres. The zone shows evidence of multiple stages of silicification indicated by cross cutting relationships and clast types within hydrothermal breccia veins. The hanging wall is strongly bleached and variably silicified in which a strongly developed stockwork of pyritic veinlets are cut by irregular veins of dark grey, banded chalcedony. One such vein was traced continuously for 22 metres.
In the West Lake area two anomalous zones, referred to as the West Lake and West Pit zones, have been identified by induced polarization surveys and trenching. At the West Pit zone trenching failed to reach bedrock but sub-crop and overburden contained abundant bright yellow clay with fragments of silicified rock and vein quartz. At the West Lake zone, located immediately west of the North zone, trenching has identified a 3-metre wide quartz stockwork zone hosting banded and bladed, pyritic, quartz-chalcedony veins.
The Obvious zone, located approximately 2 kilometres north of the North zone, comprises float boulders of quartz veins and silicified feldspar phyric rhyolite tuffs.
The West Lake Boulder zone, located near the west shore of Camp Lake, comprises a boulder train, over 600 metres in length, containing massive fine-grained quartz, silica breccias and quartz stockworks.
The Gore zone, located approximately 1.5 kilometres southwest of the North zone, comprises north trending massive silica breccias and quartz vein stockworks within dacite flows and rhyolite tuffs and is exposed over an area of 500 metres by 50 metres.
The Bari 1 and 2 zones comprise two separate silica breccia bodies and several float and sub-crop occurrences, located approximately 2.5 kilometres west of the North Zone. Local lithologies include propylitically altered dacite flows and a 50-metre thick pyroclastic breccia unit with variably silicified angular clasts. Two separate zones, the Bari 1 and Bari 2 zones are partially exposed through a thin cover of till and comprise north-trending zones of hydrothermal breccia up to five metres thick. Accessory minerals include arsenopyrite and barite and possible sulphosalts indicated by an unusual grass green coloured weathering.
In the North zone, rock geochemical values average more than 0.3 grams per tonne gold ranging to a high of 1.07 grams per tonne; silver values are in the 5 to 10 gram per tonne range. In the Central or "Ruby" zone, silver values up to 97.7 grams per tonne have been obtained; gold assayed up to 1.09 grams per tonne. Pyrargyrite was observed in two outcrops in the Central zone (Assessment Report 20864).
Work History
There is no recorded work on the Clisbako Property prior to 1989. During reconnaissance work in 1989, Eighty-Eight Resources discovered zones of argillic alteration and boulder float of pyritic, silicified rhyolite. Subsequent follow up work traced the float to its source where the main mineralized outcrops were discovered. The Clisbako Property was staked and a grid covering the 4 main mineralized zones (North, Boulder, Central and South zones) was completed and 253 rock and 1320 soil samples were collected and geological mapping completed.
In the spring of 1991, the claims were optioned by Minnova Inc. and an additional 100 units were staked and a Dighem Airborne Mag-EM survey was flown over the entire property. Grid lines were added and extended and the gridded area was geologically mapped and sampled. A total of 18 trenches were excavated covering five mineralized zones (North, South, Central, Discovery and Trail zones) all of which were mapped in detail and sampled. Based on the results of these programs a 19 hole NQ drill program was completed totaling 3023.7 metres including 1l holes in the North zone, 7 holes in the South zone and 1 hole in the Central zone. The 1991 exploration program confirmed the presence of widespread anomalous gold concentrations but failed to delineate any zones of economic significance. An historical trench sample is reported to have yielded 3.3 grams per tonne gold over 3.9 metres from the South zone (Assessment Report 26918, Figure 4).
In 1992, Minnova added 17 - 1 unit claims to the Clisbako property to cover internal fractions. The Clisbako Property by the end of 1992 comprised 37 claims totaling 417 units. The 1992 field program included a gradient array IP geophysical survey over 17 partial grid lines covering those zones identified to date in the central portion of the property. An additional seven trenches were completed in the West Lake, Gore, West Pit and Central zones. An 11 hole, 1357.9 metre NQ drill program evaluated the results of the gradient array IP survey and extension to zones identified in 1991 (l hole, Tufa zone; 4 holes, West Lake zone; 2 holes, West Pit zone; l hole, Beaver Pond zone; and 3 holes, South zone). Results of Minnova's 1991/1992 field programs failed to delineate a near surface open pit economic resource despite intersecting broad widths of strong epithermal alteration in each target area. No significant precious metal values were detected. Minnova's option expired in 1993 and the property was returned to Eighty Eight Resources. A number of photos were taken in 1993 of the Clisbako property and area (see property file numbers 821897-821915).
On October 1, 1994, Phelps Dodge Corporation of Canada Ltd optioned the Clisbako Property. Fox Geological Services Inc, on behalf of Phelps Dodge, completed a soil geochemical survey covering 22 kilometres of grid resulting in the collection of 400 soil samples. The work was completed along the Eastern margin of the claim group (Clisbako 13, 14, 15) and failed to define zones of epithermal alteration/mineralization.
In 1995, Fox Geological Services completed 58 kilometres of grid west of Camp Lake to the western claim boundary over which mapping and prospecting generated 339 rock samples for analysis. Soil geochemical surveys covered the western and central portions of the claim group along l kilometer spaced lines with detailed coverage in the Gore, Chris and Bari zones resulting in 677 soil samples. A total of 17.8 kilometres of IP surveys were completed. Drilling evaluated the West Lake boulder train (3 holes) and the Obvious zone (1 holes) totaling 700.9 metres of NQ2 drilling in 4 drill holes. A total of 708.5 metres of unsplit drill core from Minnova's 1991/1992 exploration drill programs were split and submitted for analysis. Elevated sub economic gold results were obtained in drill holes 1991-04 and 1992-22. No new untested IP chargeability targets were generated as a result of the 1995 survey. Drilling failed to encounter economic concentrations of gold with results similar to those obtained from the North and South zones
A limited field program was completed in 1996 by Fox Geological consisting of geological mapping and sampling in the Bari zone area. Following the completion of the 1996 field program, Phelps Dodge concluded the Clisbako property had been thoroughly explored and all mineralized areas located to date had been fully tested. Although a large gold bearing epithermal system had been outlined in the central claim area covering approximately 20 square kilometres, gold tenors are generally low, rarely exceeding 500 ppb. No further work was recommended and the property returned to Eighty Eight Resources.
The Clisbako claims lapsed in June 2000 and the key zones of alteration and mineralization were subsequently staked as the Bako 1 to 5 mineral claims. In 2002, Castle Metals Corp. reported its intention to evaluate the property but no record of work in that year is published. In 2002, a prospecting program was conducted on the Bako 1 to 5 mineral claims for owner Geoffrey Goodall. Fifty-two rock samples were collected and analyzed. In 2003, Bard Ventures Ltd. held the Clisbako under option from Geoffrey Goodall and a total of 23.6 line kilometres of grid was established on the southeastern and southern portions of the property in two separate grids. The grids were established on the Bako 4, 5 and 6 mineral claims over the Brooks and Discovery zones. A total of 19.0 line kilometres were surveyed. No further work in this area of the property was recommended based on the geophysical results. To the end of 2003, nine main mineralized zones had been identified, all of which have had geological and geochemical mapping and sampling, and the majority of these showings have been trenched and surveyed by IP geophysical methods. All of the significant mineralized zones have been either drill tested or mechanically trenched.
A comprehensive geological review of all the exploration work completed to the end of 2003 was finished by Bard Ventures Ltd. in April 2004. No further work was done by Bard Ventures Ltd., and the claims lapsed in 2006.
In 2006, Bako Resources Inc. purchased the Clisbako claim.
In 2008, Bako Resources Inc. conducted geological mapping of the claim.
In 2010, Manado Gold Corp. agreed to an option on the Clisbako claim from Clisbako Minerals Inc. Manado Gold Corp. then conducted geological mapping, prospecting and sampling.
In 2012, Manado Gold Corp. completed a drill program of approximately 2000 metres depth. Manado Gold Corp. also extended its option on the Clisbako claim from Pengram Corp. (formerly Clisbako Minerals Inc.).
