The Pinnacle Reef (Aplite Creek) occurrence is located at an elevation of approximately 1220 metres on a south-facing slope, north of Aplite Creek and approximately 4.75 kilometres east-southeast of the southern end of Ahdatay Lake. The Pinnacle Reef property (formerly called the Later property) is wholly owned by Pacific Empire Minerals Corp. (ca. 2017). The property is comprised of 24 mineral claims totalling 6684 hectares and covers the Aplite Creek, Ian (MINFILE 093N 236) and Sooner (MINFILE 093N 169) occurrences.
Regionally, the area lies within the Quesnel terrane, which is characterized by Upper Triassic to Lower Jurassic volcanic and sedimentary rocks of island arc affinity that have been intruded by a variety of intrusive phases related to the Upper Triassic to Lower Jurassic Hogem Intrusive Suite. Geology can be summarized as intermediate volcanics locally intruded by syenitic to dioritic dikes.
The area straddles the contact between intrusive rocks of the Hogem Intrusive Suite and volcanic rocks of the Lower Jurassic Chuchi Lake succession. Chuchi Lake succession volcanic flows, pyroclastics, and associated rock are predominate to the north and Hogem intrusive rocks dominate to the south of this contact. The Chuchi Lake succession is dominated by subaerial to submarine, maroon to green, plagioclase ± augite phyric latite, trachyte and andesite flows and pyroclastics. Regional mapping has the Chuchi Lake succession dipping gently to the south at roughly 20 degrees. Intrusive rocks of the Hogem Intrusive Suite in the area of the property are highly differentiated and span a range from hornblendites and pyroxenites to diorites and syenites, with a predominance of monzonites to monzodiorites.
The Aplite Creek occurrence is hosted within the Early Jurassic Aplite Creek Intrusive Complex (informal name); a possible phase of the larger Late Triassic to Early Cretaceous Hogem Intrusive Complex. The Aplite Creek complex is composed of equigranular and porphyritic diorite and gabbro, augite (hornblende) porphyritic monzodiorite, intrusive breccia and aplite and monzonite dikes. The complex is assumed to be Early Jurassic because it intrudes the Lower Jurassic Chuchi Lake succession of the Takla Group.
Rocks of the Aplite Creek Intrusive Complex are cut by fracture zones trending northwest (345 degrees) or northeast (060 degrees). Deeply incised gullies with good outcrop exposures are coincident with the subvertical fracture zones and form prominent topographic linears. Moderate to intense propylitic and potassic alteration envelopes (potassium feldspar, biotite, chlorite and epidote) up to 20 to 25 metres thick occur around the fractures.
Locally, a calcite-quartz breccia zone cutting potassic- and propylitic-altered andesite and/or rhyolite hosts disseminated pyrite, pyrrhotite and chalcopyrite in anastomosing quartz-carbonate veins up to 4 centimetres thick associated with epidote, chlorite, and weak potassium feldspar veining. The strongest fracture direction is reported to strike 110 degrees. Disseminated to blebby sulphides, primarily pyrite and chalcopyrite, are also present in the matrix of the country rocks, up to 100 metres away from the fractured zone in weakly altered andesite and/or basalt. Various amounts of malachite, azurite, magnetite, limonite, jarosite, and hematite are associated with the sulphide minerals. The mineralized zone is approximately 6 to 7 metres in width with a more mineralized footwall zone and less mineralized central and hangingwall zones and has been traced for approximately 30 metres along strike before being masked by overburden to the east and possibly terminated by a fault to the west. The mineralized zone strikes north 75 degrees west and dips 65 to 80 degrees south.
Disseminated chalcopyrite and pyrite with malachite staining are also reported in at least two other separate outcrops of epidote-altered basalt north and northeast of the main mineralized breccia.
Another zone of mineralization, referred to as the Junction zone, is located approximately 800 metres northeast of the main Aplite Creek zone and comprises quartz-carbonate veining with chlorite-calcite-epidote alteration associated with north-east–trending faults.
Geological units encountered in historical drilling in the Aplite Creek area consist primarily of andesitic to latitic (Takla Group) volcanics locally intruded by syenitic to dioritic dikes and ‘hybrid’ rock. Syenite and monzonite porphyry dikes, 0.5 to 3 metres wide, have been encountered in this area and are locally associated with alteration and copper-gold mineralization. Alteration, from the 1990 drilling, was described as primarily propylitic but with moderate potassic alteration, both in the intrusion and immediately adjacent. A 2-metre-thick bed of thinly laminated limestone is located southwest of the mineralized zone. The limestone bed strikes 150 degrees and dips 74 degrees northeast.
Work History
The Luc 1-4 claims were owned in 1970 by John King. Work at that time included geological mapping, magnetometer (7.3 kilometres) and a soil geochemical survey (192 samples) by the Luc Syndicate (Assessment Report 2450). A 6-metre-wide pyrite rich zone was observed cutting a rhyolite unit with malachite, chalcopyrite, calcite, and hematite. Chalcopyrite was observed primarily occurring as blebs in andesites. The geology of the work area was described as primarily underlain by andesites with minor rhyolites. A near-vertical, barren, feldspar porphyry dike was also observed.
The claims subsequently lapsed. The property was re-staked by G.C. Gutrath as the Cul 1-30 claims, with the Cul 15-18 claims covering the former Luc 1-4 claims. Calico Silver Mines Ltd. optioned the property in November 1971. The former soil geochemical survey grid was extended and filled in along selected lines with an additional 88 samples. An exploration program consisting of line cutting, mapping, rock chip sampling and soil sampling was completed (Assessment Report 3865). The geological mapping located a copper-mineralized zone on the Cul 17 and Cul 18 claims as well as relatively widespread pyrite mineralization associated with minor chalcopyrite, which indicates the possibility of a much more significant deposit in the general area. Sampling of the mineralized zone on the Cul 17 and 18 claims yielded 0.60 per cent copper over 6.0 metres (Samples 57727C through 57729C), including 1.40 per cent copper over 1.8 metres of the footwall of the mineralized breccia zone (sample 57727C; Assessment Report 3865).
Following a reconnaissance geochemical program in August 1971, Noranda Exploration Company Ltd. staked 52 contiguous mineral claims (Sooner 1-36 and Sooner 1-16 Fr.) called the Ahdatay property (MINFILE 093N 169) in October 1971 and performed exploration work in 1972 and 1973. The property was believed to cover the contact between intrusive rocks of the Hogem Batholith and Takla Group volcanic rocks, but a blanket of glacial till masks almost all bedrock in the area. The property was described as being underlain by glacial rubble and detritus of chiefly an intrusive nature, with intrusive float being dominated by granodiorite, granodiorite porphyries, syenites and diorites. Volcanic float was described as andesite and andesite porphyry (Assessment Report 3962). Several small copper anomalies with associated molybdenum anomalies were identified and a ground induced polarization survey was conducted over the area (Assessment Report 4431). Although no further work was filed for assessment purposes, it is believed that Noranda followed up with diamond drilling because historical drillcore has been observed at this location by several authors. The four holes were reportedly drilled on Sooner 16 and 27, and Sooner 14 Fr. claims. Assessment Report 13342 describes abandoned core from an early 1970s drill program at a location near 379215 E/6131996 N, which falls in the current Pinnacle Reef property boundaries.
During 1972 through 1974, Pechiney Developments Ltd. completed programs of soil sampling; magnetometer (Assessment Report 4430), induced polarization and resistivity surveys (Assessment Report 4653) and four diamond drill holes (Assessment Reports 5148 and 5212) on the Ian group of claims. The historic Ian claims were located approximately 800 metres north of the Later 11 mineral claim in the vicinity of what is now the L7 claim. Three of the holes were abandoned prematurely but one hole was completed to a depth of 152 metres.
In 1983 and 1984, BP Exploration Canada Ltd. conducted exploration on the Phil claims. In the summer of 1983, a reconnaissance rock sample returned anomalous gold and copper values from altered Takla Group volcanics (Assessment Report 12149). BP Exploration Canada staked a 20-unit claim (Phil 2) and conducted soil sampling. Following positive results, an additional 72 units (5 claims) were staked (Phil 3-7). The soil geochemistry program (1100 samples) tested for gold, copper, zinc, silver, and arsenic (Assessment Report 12149). Two anomalous zones were identified: the Aplite Creek (MINFILE 093N 085) zone and the Hilltop zone, where anomalous copper and gold was associated with strongly sheared and altered rocks. Two 1.0-metre composite chip samples (23159 and 23161) from a 5-metre-wide mineralized zone at the Aplite Creek occurrence yielded value of up to 0.850 per cent copper, 11.2 grams per tonne silver and 0.800 gram per tonne gold, whereas a sample (23162), taken to the northeast of the main zone, yielded 0.120 per cent copper, 3.2 grams per tonne silver and 0.295 gram per tonne gold (Assessment Report 12149). Later reports, in 1990, indicate that a rock chip sample, taken at this time from the Aplite Creek zone, yielded 9.45 grams per tonne gold and 0.660 per cent copper (Assessment Report 20943).
In 1984, a follow-up program consisting of geological mapping, prospecting and rock chip sampling was carried out to identify potential economically mineralized zones. Rock samples from the Aplite Creek zone yielded values of up to 1.50 grams per tonne gold (sample 821016) and 1.145 per cent copper (sample 823038?) from a zone of potassic-quartz-carbonate-pyrite–altered volcanics, whereas samples (822017 and 822025) from the Junction zone to the northeast yielded values of up to 0.255 gram per tonne gold, 2.2 grams per tonne silver and 0.09 per cent copper (Assessment Report 13342). This work indicated the potential for a mineralized zone greater than 200 metres in length.
During 1989 through 1991, BP Exploration Canada continued work on the Phil A claims. In 1989, an airborne magnetometer and very low frequency electromagnetic survey was completed over the entire Phil 2-7 claim area in an attempt to delineate possible intrusive centres and/or major structures (Assessment Report 19615). Conclusions from the airborne survey describe an extremely broken magnetic pattern with no apparent trend and a vertical magnetic gradient signature suggesting an intensely complex lithologic structure. Very low frequency electromagnetic data revealed a general north-south–striking trend. In June 1990, BP completed a ground induced polarization survey over the Phil 2, 4 and 5 claims. The report notes that three zones of anomalous induced polarization response were observed, one of the zones warranted immediate drilling (Assessment Report 20876).
In September of 1990, BP Resources completed 1067.8 metres of drilling in six holes on the Aplite Creek zone. Highlights from this program include 0.07 gram per tonne gold and 0.102 per cent copper over 20.0 metres (88 to 108 metres down hole) of chalcopyrite-bearing quartz veining and stockwork with propylitic alteration adjacent to a clay-gouge fault in hole AH90-1; 0.40 gram per tonne gold and 0.070 per cent copper over 10 metres (40 to 50 metres down hole) from a chlorite- and pyrite-rich shear zone and crowded porphyry monzonite/syenite hosting chalcopyrite and molybdenite in hole AH90-3 and 1.73, 0.41 and 6.42 grams per tonne gold with 0.004, 0.081 and 0.098 per cent copper over 4.0, 6.0 and 6.0 metres (60 to 64, 76 to 82 and 106 to 112 metres down hole) from zones of chlorite-epidote–altered andesite/latite, a potassic-altered hybrid zone and a sericite-potassic–altered monzonite, respectively, in hole AH90-4 (Assessment Report 20943). Drillhole AH90-1 was located close to the surface outcrop of the Aplite Creek zone and tested the intersection of the Aplite Creek zone and a 345-degree–striking fault zone, whereas drillholes AH90-3 and -4, located at an elevation of approximately 1250 metres, upslope and approximately 350 metres along strike to the northeast of the first hole, tested the same fault zone. Also at this time, rock chip sampling (111015, 111016 and 113045) of the Aplite Creek zone area yielded values of up to 1.78 grams per tonne gold, 6.1 grams per tonne silver, 0.921 per cent copper and 0.014 per cent molybdenum (Assessment Report 20943).
In 1991, BP completed a follow-up induced polarization survey to expand upon the induced polarization survey completed during 1990. The results from this survey were not published for assessment purposes and no further work is believed to have been completed by BP.
In 2000, the area was acquired by the Peregrine Syndicate as the Aplite 1-8 claims. Exploration in 2000 consisted of a 6.5-kilometre magnetometer survey over portions of the Aplite 2 and 4 claims to the north and south of BP’s 1990 auriferous drillholes AH 90-3 and AH 90-4. In 2001, a program of ground magnetics was conducted.
In 2007, Solomon Resources Ltd. completed a program of geochemical (soil and silt) sampling and a 1458.4 line-kilometre airborne geophysical survey on the area as the Col-Magnet property.
Following acquisition of the Later 1-12 claims in June of 2012, Pacific Empire Minerals Corp. (PEMC) conducted reconnaissance of existing logging roads, prospecting, data compilation and reconnaissance soil geochemistry. Logging roads and historical access trails were mapped and digitized and 72 soil samples were collected. The area of the Sooner (MINFILE 093N 169) showing was located and one rock sample was collected from outcrop.
In 2013, Pacific Empire Minerals Corp., in conjunction with Nation River Resources Ltd. and Indata Resources Ltd., completed a program of geochemical (rock and soil) sampling and historical data compilation on the area as part of the Col-Later-Klawback property.
On August 13, 2014, PEMC and OZ Exploration Pty Ltd. (OZE), a wholly owned subsidiary of OZ Minerals Limited, signed a Term Sheet for the potential acquisition by OZE of an interest in the Col-Later Project. Between August 31 and December 18, 2014 Peter E. Walcott & Associates Ltd. completed a total of 44.33 line-kilometres of pole-dipole induced polarization surveying over three areas. Two of the survey areas (Elbow and Sooner [MINFILE 093N 169]) were completed using 150-metre a-spacing, whereas the Later target area used 100-metre and 200-metre a-spacing. Surveyed lines were set at a nominal spacing of 600 metres. The induced polarization survey at the Sooner (MINFILE 093N 169) area targeted an ovate resistivity anomaly with a coincident magnetic anomaly identified from the 2007 Fugro DIGHEM survey. Two lines (L7400E and L8000E) were completed over this target area with positive results consistent with an interpreted porphyry copper-gold system. Pseudo sections show a complex yet coherent induced polarization chargeability anomaly and the inverted resistivity data agrees well with the resistivity map from the Fugro airborne survey.
During 2015, PEMC/OZ Minerals conducted a diamond drill program consisting of 2492.9 metres in seven holes. Drilling focused on two target areas, the Elbow and Sooner (MINFILE 093N 169) areas, where induced polarization surveys in 2014 identified areas of anomalous chargeability. In 2015, diamond drilling to the south and west of the Aplite Creek target area encountered widespread pyrite mineralization and propylitic ± phyllic ± weak potassic alteration in addition to gold mineralization with intermittent copper values. Drilling to the west of the 2015 Aplite Creek target area encountered propylitic- and calc-silicate–altered intrusive rocks, locally with anomalous copper values. One hole, DD15SON003, encountered phyllic and lesser argillic alteration in volcanic and volcaniclastic units with abundant pyrite (Assessment Report 37380).
In the fall of 2016, ML Gold Corp. completed a diamond drilling program totalling 1107 metres in three NQ-sized holes on the Elbow zone to the south. Anomalous gold values were present in all three holes although no significant copper values were encountered.
In 2017, a 12 line-kilometre induced polarization geophysical survey was completed over the southern portion of the Aplite Creek target area, extending approximately from the Aplite Creek occurrence to the Sooner (MINFILE 093N 169) occurrence area. The intent of the survey was to obtain induced polarization chargeability and resistivity measurements at a greater depth than historical induced polarization surveys completed in the same area in 1990 by BP Minerals Canada.
In 2019, Pacific Empire Minerals Corp. completed a four reverse-circulation drill holes on the Elbow and Later zones.
