The Saddle North occurs in quartz monzonite or monzodiorite bodies intruding Lower to Middle Jurassic volcanic rock of the Hazelton Group or Upper Triassic Stuhini Group lapilli tuff or reworked lapilli tuff (debris flow conglomerate) of intermediate to mafic composition. Saddle South is cut by a prominent northwest-trending brittle fracture zone that affects the Hazelton rocks. It may be the cause of the shearing, fracturing & alteration encountered during drilling of the southern contact of the Saddle South monzonite. The mean orientation of the foliation is dipping 77 towards 222. The Saddle North zone is bounded to the NE by the SE-striking, steeply-dipping “Poelzer Fault”. Mineralization is terminated by this fault & abrupt changes in lithology & alteration occur across the fault.
Initial drilling at Saddle North followed indications from early rock and soil geochemical sampling, geology, and geophysical work which outlined a kilometre-scale geochemical, magnetic and Induced Polarization (IP) chargeability anomaly coincident with local exposure of quartz-sericite-pyrite altered rocks. Reconnaissance holes TTD062 and 064, completed late in the 2017 drilling season, indicated the presence of a copper-gold porphyry system that bore some similarities to the nearby Red Chris copper-gold mine. The results from the 2018 program demonstrated the potential for a significant copper-gold porphyry system at Saddle North, with grades exceeding 1.0 per cent copper equivalent (CuEq1) and 1.5 grams per tonne gold equivalent (AuEq1) in a higher-grade core zone. It is also reported that this core zone reached from near surface (hole TTD108) to greater than 1300 metres down-dip, where it remains open. True width of the core zone is approximately 100 metres in hole TTD108, at a depth of 200 metres. Copper equivalent grade appears to increase with depth, and in mineralized thickness increases to greater than 300 metres in holes TTD093 and TTD109. The 2018 results also demonstrated that the high-grade core zone extends along strike at least 500 metres (to hole TTD102) and that it lies within a much broader, strongly mineralized envelope with a drilled strike length in excess of 650 metres, a true width of approximately 700 metres, and a down-dip extent of more than 1300 metres. This large, high-grade copper-gold mineralized zone generally appears to trend northwest-southeast and to dip steeply to the west-southwest, while the central higher-grade core zone may plunge similarly west-southwest. The 2019 drilling suggests that the high-grade core zone also extends to surface to the northwest along trend of TTD108. This large, high-grade copper-gold mineralized zone generally appears to trend northwest-southeast and to dip steeply to the west-southwest, while the central higher-grade core zone may plunge similarly west-southwest.
After the final results of the 2018 drill program GT Gold stated that "The south-southwesterly-plunging, northerly-elongate higher-grade core zone now has approximate dimensions of 1400-1500 metres (down-plunge), 250-300 metres (thickness), and 400 metres (strike). It is contained within a well-mineralized northerly-trending and west-southwesterly dipping envelope 600 or 700 metres thickness, over 1500 metres down-dip, and over 700 metres along strike. The system remains open in most directions, with highly prospective targets remaining at depth, to the west, and to the southeast."
GT Gold describes the deposit as follows. The Saddle North intrusive complex appears to be similar lithologically to the nearby Red Chris porphyry system, but with high-potassium calc-alkalic rocks predominating. The host intrusive rocks comprise equigranular to crowded hornblende feldspar porphyritic (quartz) monzonite or monzodiorite bodies, locally rich in subround inclusions, and are commonly strongly altered by potassic alteration assemblages (magnetite, potassium feldspar, biotite). The intrusive rocks appear to be bound on either side by relatively intense phyllic alteration assemblages (quartz-sericite-pyrite), as well as by peripheral propylitic assemblages (chlorite, epidote, plus/minus pyrite), mainly developed in Upper Triassic lapilli tuff or reworked lapilli tuff (debris flow conglomerate) of intermediate to mafic composition. Mineralization occurs in quartz-magnetite-pyrite-chalcopyrite veins and as closely associated disseminations, with the principal sulphide phases being pyrite and chalcopyrite.
Saddle North mineralization comprises at least three generations of veins as well as disseminated magnetite, pyrite and chalcopyrite in the host rock. From oldest to youngest, there are 3 vein generations as follows:
i). Magnetite plus/minus Quartz Veins: The earliest generation of veining at Saddle North is stringers to narrow veins of pure magnetite or quartz+magnetite. At shallow depths or in or near to zones of fractured and broken rock, magnetite is often oxidized to hematite. These veins have many orientations, with no clear pattern or prevailing orientation.
ii). Quartz-Pyrite-Chalcopyrite-Magnetite Veins: Crosscutting the early magnetite veins are quartz±pyrite±magnetite±chalcopyrite veins. These veins were emplaced over an extended period of time with later veins cross-cutting earlier ones. More magnetite-rich veins appear to have been emplaced early, with pyrite±chalcopyrite becoming more dominant over time. These veins appear to be the main host of mineralization at Saddle North. The highest grades of copper and gold mineralization coincide with where these veins are most numerous and largest.
iii). Quartz-Carbonate-Chalcopyrite Veins: The latest major set of veins at Saddle North are quartz+carbonate veins sometimes containing chalcopyrite. These veins are later than other sets. Zones where these veins are prevalent coincide with zones of increased copper mineralization, but not gold.
iv). Disseminated Sulphides and Magnetite: All mineralized zones at Saddle North contain at least minor disseminated very fine grained to fine grained pyrite±magnetite±chalcopyrite. The amounts of disseminated sulphides and magnetite increase in more intensely-mineralized, higher-grade gold+copper zones. Disseminated mineralization occurs as a halo around veins in lower-grade zones, broadening to pervasive throughout the host rock in higher-grade zones.
Saddle North displays typical copper+gold porphyry deposit alteration, with zoned alteration assemblages around a higher-grade potassically-altered core. Most of Saddle North is strongly altered, with original mineralogy and textures obscured. The major assemblages encountered during 2017-2018 drilling, from most proximal to mineralization to most distal are as follows:
1) Potassic Alteration (K-feldspar-magnetite-quartz): The core of the mineralized system at Saddle North is hosted by potassically altered intrusive rocks with abundant secondary Ksp, disseminated magnetite and quartz present, ranging from vein haloes to pervasive throughout the rocks. In less-altered rocks magnetite is present as a replacement of original mafic phases, but as alteration increases, VFgr disseminated biotite appears interstitially and becomes ubiquitous.
2) Potassic Alteration (biotite+sericite and chlorite-biotite-actinolite-magnetite-quartz): In some parts of Saddle North, an alternate, biotite-rich, potassic assemblage occurs, with biotite replacing mafic phases and becoming more ubiquitous with increased alteration intensity. This is possibly due to the original protolith being a more mafic phase of the intrusion. Even less commonly, a Chlorite+Biotite+Actinolite assemblage is seen locally replacing mafic minerals.
3) Chlorite-Sericite-Quartz-Magnetite Alteration: Moving outwards from the strongest-mineralized, potassically-altered core of the Saddle North zone a zone of chlorite replacing mafic minerals and Ser replacing feldspars and the addition of interstitial quartz and magnetite to intrusive rocks. This alteration can also be very intense, to the point of obscuring original rock textures original lithologies.
4) Quartz-Sericite-Pyrite Alteration: Further outwards from the potassic core of the deposit, alteration is dominated by patchy to pervasive quartz-sericite-pyrite. On the footwall of Saddle North, across the Poelzer Fault (Figs. 19 and 34), rocks are pervasively intensely quartz-sericite-pyrite altered, with protoliths usually indistinguishable.
5) Propylitic Alteration: In the hanging wall of Saddle North (Fig. 34), further from the core of the mineralization than the quartz-sericite-pyrite alteration, is a zone of propylitic alteration, with mafic phases being replaced by chlorite and actinolite, development of patches of epidote and hairline carbonate stringers.
Drill results released on October 16, 2019 have outlined a well-mineralized, northerly-trending and west-southwesterly dipping envelope of mineralization that has down-plunge, strike and width dimensions of 1400 -1600 metres, 700 metres and 200-560 metres respectively. Within this broader zone of mineralization is a south-southwesterly plunging, northerly-elongate core of higher-grade mineralization with a down-plunge, strike and width dimensions of 1200-1600 metres, 200-400 metres and 40-450 metres, respectively. Drilling confirmed continuity of mineralization with copper-gold grades generally increasing with depth. The system remains open at depth, and targets remain untested along strike to the west and southeast.
On February 20th, 2020, GT Gold reported results of initial Saddle North metallurgical test that showed a high-grade composite recovered 88 per cent of the copper and 67 per cent of the gold in a concentrate that graded 24.5 per cent copper and 32.2 grams per tonne gold; a lower-grade composite recovered 75 per cent of the copper and 57 per cent of the gold in a concentrate that graded 22.0 copper and 23.3 grams per tonne gold (GT Gold Corp., Press Release, February 20, 2020).
WORK HISTORY
In 2011 and 2012, New Chris Minerals Ltd. Conducted an airborne magnetic and transient electromagnetic (“TEM") airborne survey over the bulk of the Property, including over the Saddle zones (North and South) area, involving approximately 8,100 line-kilometres, with approximately 45 per cent of this flown area covered by an airborne radiometric survey.
During 2013 a reconnaissance survey of 879 soil samples was undertaken in the Saddle valley along lines spaced approximately 400 metres apart, with 50 metres between sample sites. In 2014 an in-fill sampling program (939 samples) was undertaken over the anomalous area delimited in 2013 with line spacing ranging from 50 to 100 metres, and sample spacing from 25 to 50 metres. The results from soil sampling in the Saddle target area show two coherent areas highly anomalous in gold (defined as exceeding 0.1 gram per tonne gold): the Northern Gold anomaly (Saddle North) and the Southern Gold anomaly (Saddle South MINFILE 104G 433). Concurrent with geological mapping 62 rock samples were collected for mapping purposes and analysis in 2013 from the Saddle area, followed by 66 rock samples in 2014. Samples from the gossanous zone taken in 2013 and 2014 for BT Gold on the Saddle North zone yielded 1.23 grams per tonne gold, 2.2 grams per tonne silver and 0.004 per cent copper (NI.43-101 Technical Report on the Tatogga Lake Gold/Copper Project for New Chris Minerals and Manera Captial Corporation, August 12, 2016, Sample H222239, page 53).
In 2016, a soil sampling program continued over the Saddle South zone.
On June 30, 2016, Manera Capital Corp (“Manera”) entered into an agreement to acquire New Chris Minerals Ltd. (the “NCM Agreement”). Pursuant to the NCM Agreement, Manera agreed to acquire 100 per cent of the issued and outstanding shares of NCM, making NCM a wholly-owned subsidiary of Manera. Following the concurrent closing of the New Chris Acquisition, the Greig Acquisition and the Manera Financing the resulting entity proposes to change its name to “GT Gold Corp.”
In 2017, GT Gold Corp reported that an IP ground geophysical survey carried out in June revealed a large target comprising both chargeability and resistivity anomalies trending for more than a kilometre east under glacial cover from the known Saddle North gold-in-soil anomaly. The glacial cover is believed to in part mask the gold-in-soil geochemical response, giving it a discontinuous appearance. Because the IP target remained open off-grid to the east at the close of the June program, and because local outcrops in that area display attractive quartz-sericite-pyrite alteration, an additional 10 line-kilometres of IP was undertaken to the east of the June grid, as shown in the plan view map accompanying this news release.
Prior to the expansion of the IP survey, two reconnaissance holes totalling 597 metres were completed late in July 2017. Hole TTD011, encountered difficult ground conditions and was shut down just short of the targeted IP high. A narrow visual and XRF intercept of Saddle-style mineralization was observed. A second reconnaissance hole, TTD012, drilled from a setup 440 metres northwest of TTD011 achieved its objective. An intercept at Saddle North graded 10.93 grams per tonne gold over 1.17 metre from 190.43 to 192.14 metres depth in TTD012 and; 7.62 grams per tonne gold over 0.80 metre from 86.00 to 86.80 metres in TTD011 (Corporate Presentation, BT Gold, page 18, www.gtgoldcorp.ca).
In August 2018, drilling commenced at Saddle North. An Induced Polarization (IP) ground geophysical survey completed in mid-July of 2018 confirmed that the nearer-surface geophysical signatures outlined in last year’s shallow survey extend to depths of 500 metres or more and are continuous along trend.
In 2018, GT Gold Corp reported the discovery of a new copper-gold-silver porphyry at the Saddle North target, approximately 1.5 kilometres east-northeast of the Saddle South gold discovery. Initial drilling highlights included 430 metres of 0.67 gram per tonne gold, 0.41 per cent copper and 0.89 gram per tonne silver; a later hole, approximately 200 metres metres to the northwest, yielded 363 metres of 1.02 grams per tonne gold, 0.51 per cent copper and 1.72 grams per tonne silver in 904 metres of 0.51 grams per tonne gold, 0.30 per cent copper and 0.93 grams per tonne silver (Exploration and Mining in BC 2018, page 130).
In 2019, GT Gold continued to expand mineralization to depth and along trend. Drilling also identified high-grade precious metal veins peripheral to the main body of porphyry mineralization, which included highlights of 4.11 metres of 25.42 grams per tonne gold, and 15.70 metres of 6.21 grams per tonne gold ((Exploration and Mining in BC 2019, page 33). The 10,000 metre Phase 1 drlll program was completed by September 4th 2019, with results from 8,652 metres reported. Phase 2 was also reported to be underway by September 4th and was to consist of 15,000 metres, bringing total drilling in 2019 to a total of 25,000 metres. The exploration season is expected to last into late October, with infill drilling and expansion of Saddle North continuing to be the focus.
In July 2020, GT Gold Corp Ltd. reported a mineral resource estimate for combined openpit and underground mining methods on the Saddle North occurrence of 298 000 000 tonnes indicated grading 0.28 per cent copper, 0.36 gram per tonne gold and 0.8 gram per tonne silver with an additional inferred resource of 543 000 000 tonnes grading 0.25 per cent copper, 0.31 gram per tonne gold and 0.7 gram per tonne silver using a 0.13 (openpit) and 0.22 (underground) per cent copper equivalent cut-off grade (GT Gold Corp Ltd. [2020-08-20]: NI 43-101 Technical Report on the Saddle North Copper-Gold Project, Tatogga Property, Liard Mining Division, Northwest British Columbia, Canada).
See the nearby Saddle South (MINFILE 104G 433) for additional information.
