The 72 (formerly Dirk) prospect is underlain by Upper Paleozoic marine sedimentary and volcanic rocks of the Stikine Assemblage. Faulted slivers of early Permian carbonate, late Carboniferous conglomerate and Devonian to Early Carboniferous volcanic rocks comprise the Stikine package in the immediate Dirk region. The limestone structurally overlies older rocks consisting mainly of quartzite and phyllitic quartzite. Volcaniclastic rocks, tuffs and shales are also found locally within this older sequence of rocks.
The limestone locally appears to exist as rafts within larger bodies of porphyritic plutonic rock. Highly altered rocks, presumably the same as the volcaniclastic rocks, tuffs, and shales that are found locally are in contact with the plutons. In the 72 Zone the limestone has been completely recrystallized.
Several ages of syenites intrude the sediments and volcanics. The early syenites are porphyrltic with large phenocrysts of potassium feldspar and vary from pink to grey in colour. This phase is intruded by a biotite syenite. These earlier phases are locally brecciated forming angular to subrounded fragments supported in a dolomitic matrix. Skarn alteration is locally developed around early syenite porphyries and biotite syenites.
At the main 72 Zone showing sits a large intrusive breccias which cuts and contains abundant fragments of the potassium feldspar porphyry and megacrystic dikes, and is cut by the later biotite bearing syenite dykes. Alteration within and haloing the breccias is intense, and a pervasive “baked” texture is dominant across the entire area,
Sulphide mineralization at the 72 prospect consists of chalcopyrite, bornite, chaclocite and pyrite (Assessment Report 34623). Gangue minerals include magnetite, hematite, epidote, chlorite, green mica and garnet. The gangue minerals are found in limestone which has skarn alteration adjacent syenite porphyries. The sulphides form banded zones at the lower limestone-volcanic contact. Chalcopyrite was also noted in the syenite breccia matrix 100 metres northwest of the Dirk showing. Abundant chalcopyrite and bornite oxidize to form gossans of malachite and azurite.
More recent descriptions contradict early reports, saying that the main 72 Zone consists of bornite, covellite, and trace chalcopyrite mineralization (Assessment Report 34623). Mineralization occurs in irregular, discontinuous, resistively weathered veins and breccia bodies. The veins are seen cutting large, silicified limestone rafts within the syenite intrusive complex east of the intrusive breccia and as less obvious, fine veinlets of bornite within dusty white altered limestone. A skarn assemblage of euhedral epidote-garnet replacement within the limestone also contains copper mineralization seen as disseminated to coarse and clotty chalcopyrite plus/minus bornite. At the contact with the limestone rafts, advanced argillic alteration can be seen as feldspars become white and dusty, and vuggy textures indicate strong leaching of primary minerals.
The weighted average of chip samples taken at the showings yield 4.6 per cent copper 3.09 grams per tonne gold, 85.72 grams per tonne silver over an average 1.2 metres (Assessment Report 22377).
In 2012, drilling on 72 Zone intersected copper-gold-silver, high-sulphidation, porphyry and breccia-hosted mineralization over significant widths that remain open to the west and south. In this zone, drilling encountered a 5.42 metre horizon that assayed 3.09 grams per tonne gold, 1.33 per cent copper and 27.55 grams per tonne silver. This intercept occurred within a wider zone of mineralization, 10.47 metres in width, which assayed 1.67 grams per tonne gold, 0.49 per cent copper and 6.21 grams per tonne silver. (Assessment Report 33620). The occurrence of the sulphide minerals bornite, digenite, chalcopyrite and chalcocite at the 72 zone, in addition to anomalous concentrations of selenium and tellurium, suggest the 72 zone may be a deep to intermediate type of high-sulphidation (HS) epithermal zone (News Release, Romios Gold, October 10, 2012). Deep HS types of mineralization often occur along faults or other favourable ground adjacent to or above major mineralizing porphyry systems and often within carbonaceous stratigraphy.
The Knob showing was visited in 2013. It is located about 300 metres northwest of the main 72 zone showing, was investigated due to its proximity to the 72 Zone main showing and their similar alteration and field relations (Assessment Report 34623). There were small (approximately 5 metres diameter) breccia zones that hosted bornite, but these were not as large nor as rich as the breccias at the main showing of the 72 Zone. At the Knob area a chip line graded 0.19 per cent copper and 3.24 grams per tonne silver over 5.5 metres. (Assessment Report 34623).
The Birthday Jim was also sampled in 2013. This showing exhibits similarities to the Knob and the main showing of the 72 Zone. It is located further northwest from the 72 zone than the Knob. It consists of blocks of limestone sitting within a large porphyry body that have been altered to garnet, epidote, and actinolite; and have been cut by veins and breccias containing specular hematite with bornite. Samples from this area are very rich in hematite however; they proved to be relatively poor in bornite, with only 0.24 percent copper at their highest (Assessment Report 34623).
Crystal Lake's 4 widely spaced diamond drill holes tested a 700 by 300 metre area. All of the holes intercepted widespread sulphide mineralization and alteration styles characteristic of a porphyry copper-gold system. The third diamond drill hole (STDDH19-006) cut through stockwork-hosted and disseminated chalcopyrite-bornite mineralization associated with a potassic alteration zone. A 56.35 metre diamond drill core interval graded 0.45 per cent copper, 0.33 gram per tonne gold, and 3.44 gram per tonne silver, including a 22.28 metre intercept with intense potassic alteration and high-grade hypogene mineralization grading 0.89 per cent copper, 0.71 gram per tonne gold, and 6.65 grams per tonne silver (News Release, Crystal Lake Mining Corporation, October 8, 2019).
Work History
The Dirk claims were first staked by Newmont Mining Corporation in 1972 to cover copper mineralization discovered in 1971. Exploration efforts on the property were completed in 1972 and consisted of 1:9600 scale mapping over the entire claims. Three “A” size drill core holes over the main Dirk showings were drilled. Airborne Magnetics was flown at approximately 244 metre line spacings, oriented north-south. Ground Magnetics were completed over magnetic anomalies seen in the airborne magnetic results. The Dirk and Ridge grids were completed over known areas of outcropping mineralization; the Icecap grid was completed over a permanent snowfield northeast of the Dirk Grid where a small, clearly defined magnetic high was seen in airborne results. Coarse geophysical maps are given in the 1972 assessment report, but no assay results from surface or drillcore sampling are included (Assessment Report 4150).
The Au claim group (Au 1 and 2 and the Biz and Nez claims) were staked in 1987 on behalf of Chandi Resources Corporation. In November 1987 an orthophoto map of the claims was prepared and an airphoto interpretation completed.
In 1988, a 78-kilometre airborne magnetics and electromagnetics survey was carried out over the Au 1 and 2 and the Biz and Nez claims of Chandi Resource Corp. A strong magnetic high feature trending in a northeast-southwest direction for approximately 4 kilometres with a width greater than 1 kilometre on the Au 1 and 2 and Biz claims. The Dirk showing (magnetite-chalcopyrite-bornite skarn) is situated near the southeast corner of this anomaly. A second major-magnetic anomaly occurred on the Nez claim.
In 1990 the Au claims were optioned to Mountain Province Mining Inc. In 1991, Mountain Province Mining conducted a program consisted of mapping of rock exposures and sampling of mineralized specimens over several traverses around and over the "Dirk" showings on the claim. Thirty-two rock samples were collected.
Over the 2009 Season, Romios Gold Resources completed exploration on the Dirk claim group as part of a larger exploration program on the Newmont Lake and Trek properties. Exploration work consisted of geological mapping and geochemical rock sampling over the Dirk and Telena showings. In total, 32 rock samples were taken from bornite and chalcopyrite bearing copper-gold mineralization on the claims.
Over the 2010 season, mapping, prospecting and geochemical rock sampling were completed over the Dirk, Ridge and Telena showings. In total, 62 grab and chip samples of bornite and chalcopyrite bearing copper-gold mineralization were collected. Assessment Report 32050).
In 2011, Romios completed four diamond drill holes collectively totalling 743 metres in length on the Dirk property during August of 2011 which encountered copper-, gold- and silver-bearing sulphides near surface in all the drill holes within breccias and intrusions.
In 2012, Romios completed drilling, ground magnetics, audio-magnetotellurics (“AMT”) and borehole geophysics on the 72, Ken and Northwest Zones in addition to sample collection and general prospecting. Fifteen (15) NQ-size helicopter-assisted diamond-drill holes, totaling 2,616 metres, were drilled at the Northwest, 72, and Ken Zones on the Newmont Lake Project in 2012. Drill holes at the Northwest Zone and Jazzman both confirmed historical drill results and additionally indicate a new “Northwest Deep” mineralized horizon located approximately 75 metres below the Northwest Zone’s existing NI 43-101 Inferred Resource. On the 72 zone, 1427 metres of drilling were completed in 10 holes.
The 2013 exploration work at the ’72 Zone was directed at an area known as “The Knob”, where chip sampling was performed (Assessment Report 34623). It sits approximately 300 metres northwest of the main 72 zone showing, and the site of 2012 drilling. In total, 36 chip samples were from across the marble-exoskarn body that forms the Knob and three grab samples from an area further northwest (Birthday Jim) were taken for geochemical assay.
In 2013, Geotech Ltd. carried out a helicopter-borne electromagnetic (ZTEM) and aeromagnetic geophysical survey for Romios Gold Resources Inc over the Newmont Lake Block, comprising parts of the Newmont Lake property (Geophysics Report, Assessment Report 35016, Appendix VI). Twenty-one mineral occurrences were covered by this survey including the 72 prospect.
In 2014, Romios Gold Resources Inc. conducted a prospecting and sampling program that included the evaluation of various showings and mineralized occurrences on the Newmont Lake and Trek Properties. A total of 314 rock chip samples and reconnaissance rock samples were taken, and 26 stream silt samples were also collected.
In 2015, Romios Gold reported that a program of additional prospecting and sampling was carried out on the Burgundy Ridge discovery.
No 2016 or 2017 work was reported.
In 2018, Romios Gold Resources Inc successfully completed the airborne magnetic and VTEMTerrain Time Domain electromagnetic survey over three of the Company's most prospective exploration targets on its Newmont Lake property in the "Golden Triangle" of British Columbia News Release, Romios Gold, Feb.26, 2018). The survey was covered approximately 97 square kilometres at a line spacing of 125 metres. The three survey blocks covered are referred to as the Northwest Zone, Ken Zone and the Dirk claims and cover a variety of copper-gold-silver targets including skarns, mantos and porphyry-style occurrences (for further details on the various mineralized targets see Romios' news release dated January 31, 2018). The 72 prospect is located on the Dirk Block as are the Burgundy Ridge (104B 325) and Telena (104B 428), all which occur along a 3 kilometre long oval magnetic high where scattered outcrops are exposed. None of the known showings along the ridge were detected by the VTEM survey which was thought to be due to the disseminated, poddy and vein-like nature of the sulphide mineralization.
Crystal Lake Mining announced that it had signed a Letter Agreement with Romios Gold Resources Inc. for an option to acquire a 100 per cent interest in the 436 square kilometre Newmont Lake Project from Romios Gold.
In 2019, Crystal Lake Mining Corp conducted a drill program, on the Burgundy Ridge prospect area (104B 325) and the Northwest deposit. They also conducted extensive grassroots exploration. Crystal Lake sampled and mapped the Cuba-Thumper trend along its 2.5 to 3.2 kilometre length. This trend is found between the Cuba prospects (104B 334 and 440) in the north and Thumper (104B 445) to the south. The trend is characterized by a high-grade high-grade silver-zinc-copper-lead barite system.
In October, 2019, Crystal Lake Mining Corporation drilled 4 diamond drill holes on the 72 zone and subsequently announced their discovery of a new copper-gold porphyry mineral zone. The discovery is 250 metres west-northwest of historic high-grade copper-gold skarn-type mineralization drilled by the previous operator (Romios Gold) and about 2 kilometres northeast from newly discovered analogous surface mineralization at “Rock Islands” which may be indicative of a larger porphyry system.
See Burgundy Ridge (104B 325) and Talena (104B 428) for related geological and work history details.
Refer to Northwest (104B 281) for a more comprehensive discussion of the Newmont Lake property work history.
