The Boomerang occurrence is located at an elevation of approximately 1770 metres on the south side an east-west–trending ridge, southeast of Mount McDame and approximately 4 kilometres east of the town site of Cassiar.
The area is underlain by the Upper Paleozoic Sylvester Allochthon located on the northeastern margin of the Lower Cretaceous Cassiar Batholith. The Sylvester Allochthon is a fault bound imbricate assemblage of Mississippian to Upper Triassic Slide Mountain Complex regionally metamorphosed (greenschist) oceanic rocks thrust over the sediments of autochthonous North America. The assemblage contains basaltic to andesitic flows, pyroclastics, argillites, limestones, greywacke, chert, listwanite and quartz veins.
The occurrence area lies on the southwest limb of the allochthon, which has its major axis trending northwest; the bedding dips vary from 45 degrees to subvertical. The volcanics contain three joint sets, the dominant being roughly east with a steep southerly dip. Most of the quartz veins share this attitude.
Mineralization consists of tetrahedrite (massive), sphalerite, trace chalcopyrite and pyrite. Free gold has also been identified in float samples from the vein area. The quartz-carbonate alteration of a parent ultramafic has produced listwanite, which is associated with increased mineralization in the quartz veins. Malachite and azurite are present as the alteration products of tetrahedrite. The vein strikes 122 degrees with a dip of 67 degrees to the southwest and has an average exposed width of 2.0 metres. A north-south–trending fault, 60 metres east of the main trench exposing the vein, appears to truncate the vein with a possible right-lateral offset.
Other quartz veins hosting tetrahedrite or an extension of the Boomerang vein are exposed in trenches located approximately 150 and 300 metres east-southeast of the main vein zone. The veins average approximately 1.5 metres in width along a 97-degree trend with a dip of 78 degrees south.
In 1985, a grab sample (6166) from the Boomerang vein area assayed 65.0 grams per tonne silver, a chip sample (6240) from the eastern (second) vein assayed 71.9 grams per tonne silver with 0.63 gram per tonne gold and a sample (6246) from a 0.5-metre quartz vein with tetrahedrite exposed in trench 100E, further to the east-southeast of the main Boomerang vein, assayed 0.9 gram per tonne gold and 51.3 grams per tonne silver (Assessment Report 14375).
In 1986, a drillhole (E86-4) located several hundred metres northeast of the Boomerang vein in an area of high gold-in-soil geochemical anomaly yielded 8.1 grams per tonne silver over 0.65 metre (Assessment Report 15396).
In 2007, four rock samples (145833 through 145836) of mineralized micaceous zones parallel to bedding and quartz veins, taken from approximately 300 metres northwest to 700 metres north-northwest of the Boomerang occurrence, yielded from 200 to 300 grams per tonne silver with up to 0.67 per cent copper, 0.91 per cent lead, 0.93 per cent zinc and 0.32 per cent antimony (Assessment Report 29978). It is unknown if these samples were from outcrop or float.
In 2018, an undescribed outcrop sample (R9550), located downslope to the south of the Boomerang vein at an elevation of approximately 1580 metres, assayed 1.29 grams per tonne gold and 0.52 per cent copper (Assessment Report 38310).
Work History
In 1980, the area was staked and examined as the Elan 2 and Dee 1-4 claims by AJM Explorations Limited. In 1981, A.J.M. Explorations Ltd. soil sampled the area immediately south of the occurrence as the Angus and Murray claims. Also at this time, in 1980, the Dekalb Mining Company staked the Dekalb 1-6 claims immediately east of the occurrence area. Prospecting, geological mapping, trenching, geophysical and geochemical surveys were conducted during the 1980 and 1981 field seasons. During 1982 through 1985, AJM Explorations Limited and later Erickson Gold Mining completed programs of geological mapping, trenching and geochemical (rock and soil) sampling on the area. In 1986, Erickson Gold completed four diamond drill holes, totalling 313.0 metres, on the Joab and Dee 2 mineral claims.
In 2007, the Boomerang claim was prospected and sampled by G. Diakow and J. Hope. In 2012, a photogeological (structural) interpretation program was completed on the Judy claims, located immediately west and north of the occurrence.
During 2008 through 2010, Hawthorne Gold Corp., later China Minerals Mining Corp., completed regional programs of geological mapping, geochemical (rock and soil) sampling and 11,657 line-kilometres of airborne magnetic, radiometric and electromagnetic surveys on the area as the Cassiar Gold property. In 2018, Cassiar Gold Corp. completed a program of rock and soil sampling on the area.
In 2019, Margaux Resources completed a program of prospecting, geological mapping and rock sampling on the Cassiar Gold property. In 2020, Cassiar Gold Corp. completed a program of regional photogeological interpretation, prospecting and rock sampling on the Cassiar Gold property.
