Summary:
Mineralization
Four gold mineralization areas presently exist on the Bradshaw Project.
Bradshaw Deposit
The Bradshaw Deposit comprises a geological Main Zone and several lesser Hanging Wall Zones. Gold mineralization in the Main Zone occurs primarily within a fractured and brecciated altered horizon previously interpreted as a shear zone in hanging wall basaltic flow rocks at or near the contact with steeply north-dipping (85°) footwall ultramafic rocks to the south.
The mineralization is not confined to narrow vein-like structures (as can be seen in many other deposits in the area) but rather in a more massive/tabular structure that is consistently present throughout the mineralized horizon. This characteristic is shared by the major past gold producers in the Porcupine camp including Hollinger, McIntyre and present producer Goldcorp at their Dome and Hoyle Pond deposits.
Within the geological Main Zone, higher-grade gold mineralization is localized along the footwall of the horizon, termed the MZ1 Zone (previously referred to as M1 Zone - Harron, 2006) and occasionally along the hanging wall of the horizon, termed the MZ2 Zone (previously referred to as M2 Zone - Harron, 2006). Both gold mineralized zones appear to rake steeply to the east based on current drill data. Their variation in widths may reflect tectonically controlled shoots or boudinage structures.
Sheridan Deposit
In the northwest part of the Frankfield Block, the Sheridan Gold Deposit (formerly the Texmont Deposit) is hosted in a carbonate, hematite and sericite altered shear zone within a sequence of tholeiitic basalt flows. The shear zone strikes N086°E and dips 75° to the north. Sheridan is a sulphide mineralized zone of 3-5% disseminated pyrite and very fine microscopic arsenopyrite with quartz vein flooding. Intex reported in 1982 that the Sheridan Gold Zone contained 103,400 t averaging 7.54 g/t Au across and average width of 3 metres along a strike length of 152 metres and to a depth of 75 metres.
Dowe Gold Showing
The Dowe showing is located on the southeast part of the Frankfield Block. Gowest drilled a single hole GW13-242 at the showing, in 2013. The hole returned an anomalous gold value of 0.80 g/t Au over 0.7 metres in the altered mafic volcanics, 170 metres down dip of the Dowe gold zone. This zone has reported gold drill intercepts of 2.86 g/t Au over 3.38 metres, 1.8 g/t Au over 12 metres, and 1.9 g/t Au over 3.4 metres from drilling in 1997-1998 by previous owners. Mineralization is reported to occur in quartz veins within a wedge of mafic volcanic rocks enclosed in ultramafic rocks. The mafic rocks are reported to be ankeritized and slightly silicified. Visible gold has been reported, together with pyrite. No arsenopyrite has been reported. The showing is reported to have a strike length of at least 150 metres and has not been closed off.
Roussain Gold Showing
The showing is located 3 km northeast of the Bradshaw Gold Deposit on the North Tully claim group. Drilling by Newmont exploration in 1983 outlined a northwest trending carbonate zone in basalts on the south side of an ultramafic horizon and in association with a graphitic horizon. Gold intercepts of 7.1 g/t Au over 1.5 m, 1.65 g/t Au over 5.1 m, and 1.65 g/t Au over 1.8 metres were reported from this drilling. Gowest undertook an exploration drilling program on Roussain consisting of six holes (2,401 metres) in February-March 2013. The Gowest drilling results confirmed and exceeded the historic 1980's assays. Four gold mineralized zones were identified in hole GW13-236 with the best gold zone returning 5.01 g/t Au over 4.4 metres which included 12.00 g/t Au over 0.7 metres. The wider upper gold zone is hosted within a pyritic sedimentary unit and the three other gold zones in carbonated-silicified basalts. These three zones, which includes the 5.01 g/t Au over 4.4 metres are characterized by disseminated arsenopyrite-pyrite mineralization, which is a similar environment to that hosting the Bradshaw Gold Deposit. The Roussain gold zones are open to the southeast and at depth.
Deposit Types
The sulphide enrichment gold deposit model best describes the mineralization of the Bradshaw Deposit.
The sulphide enrichment deposit model is characterized by a dominance of sulphide minerals over quartz veins, and is localized in shear zones adjacent to rheologically differing mafic to ultramafic volcanic rocks of tholeiitic petrochemistry. Mineralization typically comprises native gold associated with disseminated to massive arsenopyrite and vein hosted pyrite and arsenopyrite in silicified chloritic and sericitic schists, within a broad zone of potassium metasomatism and wall rock sulphidation (disseminated pyrrhotite and pyrite). Carbonatization of the wall rocks is a less conspicuous feature than silicification. Pervasive silicification and silicate alteration minerals developed within the shear zone consists of quartz, albite, chlorite, actinolite, tourmaline and amorphous carbon, suggesting a dominance of silicic and potassic alteration. Canadian examples of sulphide enrichment gold deposits include the Madsen and Starratt-Olsen deposits in the Red Lake Camp, (Durocher, 1983) and the ULU deposit in the High Lake Greenstone Belt in Nunavut. The best Ontario examples of sulphide enrichment gold zones include the gold zones of the Holloway and Holt mines about 100 km east of Timmins (Valliant and Bergen, 2008), and the flow ores of the historic giant Kerr Addison Mine about 150 km southeast of Timmins. In the Porcupine Timmins Gold Camp documented examples include the Bell Creek Mine Zone (Pressacco, 2011) and the historic Moneta Mine gold zones.
In the search for sulphide enrichment and quartz lode gold mineralization magnetic, induced polarization/resistivity (IP/RES) surveys can define favourable host environments. Alteration destroys the magnetic minerals in mafic and ultramafic rocks resulting in subdued magnetic patterns. Silica alteration results in enhanced resistivity, while the presence of arsenopyrite and other sulphide species in the quartz veins and their alteration envelopes produce a positive chargeability response. Surveys over other Canadian examples of this type of mineralization have demonstrated the utility of IP/RES and mise-à-la-masse survey methods in defining mineralization. Previous geophysical surveys on the Project have not included IP/RES surveying due to the thick clay overburden of the area, but have relied on HLEM surveys to delineate graphitic horizons in the volcanic stratigraphy (Trinder, 2011).
Typical soil geochemical surveys are not particularly effective in the Bradshaw Project area, as a result of extensive thick overburden cover (greater than 15 metres and locally up to 50 metres thick). Gowest has conducted several SGH geochemical surveys over various parts of the Project area in an effort to "see through" the deep overburden. The SGH results are being evaluated and compiled by Gowest with other exploration data sets to determine its effectiveness on the Bradshaw Project.