The Silver Pond (South) occurrence is located on the west side of a ridge separating Caribou Creek to the east and Lawyers Creek to the west, approximately 6.5 kilometres south of the Toodoggone River.
The Lower Jurassic Toodoggone Formation (Hazelton Group) volcanic rocks form a northwest-trending belt, at least 90 kilometres long and 35 kilometres wide, preserved between undivided Lower to Middle Jurassic Hazelton Group rocks to the east and the Upper Cretaceous to Eocene (?) Sustut Group rocks to the west. Where observed, they rest structurally on Upper Triassic Takla Group rocks.
Toodoggone pyroclastic and epiclastic volcanic rocks are a predominantly calcalkaline andesitic to dacitic subaerial succession. The region as a whole resembles a synclinorium in section from northwest to southeast. Potassium-argon studies of hornblende and biotite indicate the age of Toodoggone volcanism ranges from 204 to 182 Ma. This age appears to be divisible into two main groups: an older, lower stage of volcanism dominated by andesitic pyroclastics and flows characterized by widespread propylitic and zeolitic alteration; and a younger, upper stage of volcanism dominated by andesitic ash-flow tuffs which generally lack significant epithermal alteration. All the known epithermal gold-silver deposits and occurrences are restricted to the lower Toodoggone Formation volcanics and underlying units (Fieldwork 1988).
Toodoggone volcanic rocks display broad open folds or homoclines with attitudes generally less than 25 degrees dipping predominantly to the west. The overlying Sustut Group sedimentary rocks are structurally unaffected and are horizontal. A northwest-trending set of younger, steeply dipping faults and synvolcanic half-graben margins are the dominant structure in the region. Major structural breaks are postulated to have been caused, or be the result of, a northwest-trending line of volcanic centres. Small stocks are also aligned northwest, suggesting they were also influenced by the same structural trend. Subsequent to volcanism and intrusion, young faults are recognizable as northwest-trending lineaments. Major north-northwest fault systems are from west to east: Attorney; Moosehorn-McClair; and Saunders-Jock. Most prominent gossans are aligned along this configuration of faults. The Attorney fault system passes through the Lawyers property.
Two distinct mappable sequences of the Toodoggone volcanics, consisting of an older pyroclastic quartz andesite crystal tuff sequence (Adoogacho Member) and a younger trachyandesite sequence (Metsantan Member), are evident on the Silver Pond property. These volcanics strike northeast and dip 5 to 20 degrees to the northwest. The two sequences are intruded by steeply dipping rhyolite to rhyodacite dikes and are generally associated with steeply dipping fault zones. These are overlain by pyroxene basalt. The volcanic sequence in stratigraphic order is composed of: a) quartz andesite crystal tuff, b) fine-grained to aphanitic chocolate brown tuff, c) welded trachyte tuff, and d) trachyte crystal and crystal lapilli tuff with interbedded volcanogenic greywacke. Several north- northwest striking faults have been identified and are slightly offset by younger east-striking faults. The north-northwest striking faults apparently were the conduits for the mineralizing fluids which also gave rise to mineralization at the Silver Pond (North) (094E 069), Silver Creek (094E 075), Amethyst (094E 160), Ridge (094E 162) and West (094E 163) prospects. The Toodoggone volcanics are affected by widespread weak propylitic alteration and weak silicification.
The southern portion of the Silver Pond property is capped by younger Sustut Group conglomerates in slight angular unconformity with the underlying Toodoggone volcanics.
Alteration associated with structurally controlled epithermal mineralization, in the area, consists of pervasive silicification grading outward into weaker silicification, sericitization, argillic and potassic alteration. An alteration zone, two kilometres across, covers much of the area and is marked by a gossan of abundant goethite, jarosite and hematite. Quartz, alunite, kaolinite, montmorillonite, dickite, illite, sericite, and minor amounts of barite, fluorite, limonite and pyrite comprise secondary minerals in intermediate to advanced argillic-altered zones (Forster, 1984).
Two general styles of acid-sulphate type epithermal gold-silver mineralization occur on the Silver Pond property. These consist of vein and breccia-type ore shoots and pods, such as the Silver Pond (West) prospect (094E 163) and the Silver Pond (Silver Creek) prospect (094E 075); and high-level stockwork-type mineralization such as the Silver Pond (North) prospect (094E 069). Gold and silver are generally absent from intensely altered regions in the area, with pyrite and magnetite being the only visible metallic minerals (Forster, 1984).
The Silver Pond (South) prospect is regarded as a southwest splay off the Cliff Creek zone of the Lawyers mine (094E 066). It was originally defined by a coinciding magnetic low, a VLF conductor, and a geochemical gold anomaly peaking at 1.95 grams per tonne (Assessment Report 16952).
The Silver Pond (South) prospect is characterized by narrow silica stringers in hydrothermally altered andesite. Gold mineralization is confined to millimetre and centimetre-wide silica stringers and veinlets. The zone is open at depth and along strike.
The M Grid zone, located approximately 300 to 400 metres northwest of the main South zone, comprises four principal zones of clear to white, massive, comb and druse quartz, quartz-chalcedony veining, brecciation and silicification with local millimetre-scale vein selvages of pale pink adularia, trace to 5 per cent pyrite, and local traces of fine-grained acanthite. The zones, exposed by trenching in 2004, are from 1 to10 metres wide and have been traced for 400 metres along their northwest strike.
In 1984, sampling of trenches on the South zone yielded values of 0.28 gram per tonne gold and 2.4 grams per tonne silver over 132 metres, including 2.64 grams per tonne gold and 10.5 grams per tonne silver over 1.0 metre, in the northernmost trench (no. 3) and 2.19 grams per tonne gold over 3 metres, including 5.25 grams per tonne gold over 1 metre in the no. 1 trench, located approximately 200 metres south of the no. 3 trench (Assessment Report 12911).
In 1985, a sample from a new trench yielded 2.40 grams per tonne gold over 1 metre, whereas diamond drilling yielded intercepts of up to 1.42 grams per tonne gold and 24.2 grams per tonne silver over 0.5 metre in hole 85-18 (Assessment Report 14700).
Analytical results from a number of interesting intersections were obtained in 5 of 7 drillholes in this zone in 1987. The highest gold and silver values were 14.6 grams per tonne and 24.00 grams per tonne respectively over a 2-centimetre-wide stringer. The weighted averages of 8 significant intersections with 1 gram per tonne or greater gold and silver are, 2.155 grams per tonne and 22.124 grams per tonne respectively over 1-metre true width (Assessment Report 16952).
In 1990, a drillhole (90-CC-107), located approximately 50 metres northeast of the later identified M Grid zone, intercepted multiple zones of veining yielding up to 6.3 grams per tonne gold and 816 grams per tonne silver over 0.5 metre (Assessment Report 38447).
In 2001, a composite float sample (W-R8) from the northwest extension of the South zone (M Grid) yielded 51.62 grams per tonne gold and 272.6 grams per tonne silver (Assessment Report 26728).
In 2003, trenching on the area of the area of 2001 composite float sample, located on the northwest extension of the South zone (M Grid), identified narrow zone of quartz veining and argillic-altered zones with quartz fracture filling yielding up to 0.30 gram per tonne gold and 99.0 grams per tonne silver over 0.45 metre, whereas nearby float and boulder samples yielded values of up to 44.84 and 4.95 grams per tonne gold with 2386.8 and 58.2 grams per tonne silver, respectively (Assessment Report 27291).
In 2004, results from chip sampling of trenches on the M Grid zone included 1.5 metres grading 7.06 grams per tonne gold and 66.0 grams per tonne silver (Assessment Report 27663).
In 2018, two rock samples from the M Grid zone yielded 6.6 and 6.8 grams per tonne gold with 53.3 and 141 grams per tonne silver, respectively (Assessment Report 38447).
In 2020, drilling on the M zone yielded up to 5.6 grams per tonne gold and 24.8 grams per tonne silver over 12 metres in hole 20CCRC019 (P&E Mining Consultants Inc. [2021-06-28]: Technical Report and Updated Mineral Resource Estimate of the Lawyers Gold-Silver Property, Omineca Mining Division, British Columbia, Canada).
Work History
The area has been explored in conjunction with the nearby Silver Pond (West) occurrence (MINFILE 094E 163) and completed exploration history of the area and property can be found there.
