The Rampalo occurrence is located on the northern slope of Lightning Peak, approximately 2 kilometres northwest of the summit. This occurrence includes the Silver Lump adit, 135 metres to the east of the upper Rampalo adit.
The Lightning Peak area is underlain by limestone and greenstone of the Devonian-Triassic Harper Ranch Group. These are underlain and intruded by granodiorite and diorite of an unnamed Middle Jurassic intrusion. Quartz porphyry dikes are common in the Harper Ranch Group; pegmatitic variations are sometimes associated with mineralization in the Lightning Peak camp. Several remnants of Miocene-Pliocene Chilcotin Group plateau basalts are found in the area, including the summit of Lightning Peak.
The occurrence has been explored by three adits that expose quartz veins and shear zones.
The uppermost, 18-metre adit follows a vein that strikes 37 degrees and dips 62 degrees to the southeast. The vein varies in width up to 60 centimetres, and is associated with a quartz porphyry dike. Near the portal, the vein is offset approximately 1 metre by a fault striking north and dipping 45 degrees to the west. Disseminated pyrite and, locally, minor amounts of galena and silver-rich sulphides are found in the vein. Silver assays are reported to be highest near the fault. Native silver has also been found in high-grade samples.
Another adit, located 50 metres to the northeast, reportedly intersected the downdip extension of this vein approximately 15 metres below and 60 metres north of the upper adit.
The portal of the lowest adit, 135 metres east of the upper adit, is located on the Silver Lump Crown grant. Although known as the Silver Lump adit, it is a crosscut driven by T. Cortiana, and approximately 100 metres of its 135-metre length is on the Rampalo Crown grant. The adit terminates roughly under the upper adit's opencut. Exposed in the adit is a 7-centimetre wide vein that appears to be repeated by a series of parallel fractures striking north and dipping 40 degrees west. Approximately 5 metres from the portal, a 30-centimetre wide quartz vein cuts across the adit in a shear zone. The vein dips steeply to the east and underlies a 3-metre wide quartz porphyry dike.
A channel sample of quartz with sparse sulphides from a lens at the portal of the no.3 drift assayed 1.4 grams per tonne gold with 322.8 grams per tonne silver, whereas a sample of ‘high-grade’ ore yielded 15.0 grams per tonne gold with 2927.5 grams per tonne silver (Property File - Unknown [Unknown]: Report - Lightning Peak Area).
In 1967, a dump sample assayed 2.1 grams per tonne gold and 410.4 grams per tonne silver (Property File - J.C. Stephen [1967-10-20]: Report - Lightning Peak Area - Mastodon Highland Bell Mines Ltd.).
In 1992, a chip sample from a 60-centimetre wide quartz vein in the upper Rampalo adit containing minor calcite stringers and mineralized with pyrite, tetrahedrite and minor galena and sphalerite assayed 12 grams per tonne gold and 1193 grams per tonne silver, whereas a sample of quartz and pyrite from the upper adit dump assayed 15.5 grams per tonne gold and 314 grams per tonne silver (Assessment Report 22875). Many other samples collected in the Rampalo and Silver Lump adits returned anomalous silver values.
The Rampalo claim, staked in 1897, was the first claim located in the Lightning Peak area. It and the adjacent claim were Crown granted in 1902 as the Rampalo (Lot 2408) and Silver Lump (Lot 2409), respectively. A 1930 report describes the adits, which vary in length from 18 to 118 metres. Initial development consisted of drifting in two adits, followed by a 118-metre crosscut to explore the vein below and to the east of the other adits. This development work was carried out by T. Cortiana during the period 1919 through 1921.
In 1967, Mastodon-Highland Bell Mines prospected and sampled the area. In 1968 and 1969, International Mine Services Ltd. carried out a number of geochemical and geological surveys of the Lightning Peak area for the Great Horn Mining Syndicate. The area around the Rampalo occurrence was covered by the Peak claim group during this period; however, little attention appears to have been paid to the Rampalo occurrence.
In 1984 and 1985, Zalmac Mines Limited carried out VLF-EM and IP surveys over portions of the BIG P 1, 2 & 3 claims, which surrounded but did not include the Rampalo showing. The surveys identified three polarizable anomalies coincident with east-west VLF-EM conductors. It was speculated that these anomalies might represent mineralized shear zones. Several northeast-trending conductors were detected by a 1985 VLF-EM survey. It was suggested that they could be extensions of the Rampalo, Victoria (MINFILE 082ENE076) and Lumpy (MINFILE 082ENE031) structures.
During 1987 through 1989, Grazina Resources Ltd. carried out several exploration programs on their Silver Lump property, which included the Silver Lump Crown Grant (by this time reverted) and several claims around the Lightning Peak area. Geological mapping, soil sampling, VLF-EM and magnetometer surveys were carried out, mostly in an area to the north of the Rampalo and Silver Lump adits. Coincidental soil, VLF-EM and magnetometer anomalies were found.
The Rampalo Crown grant was forfeited in 1992, and was staked as the Rampalo Fraction by Zalmac Mines Limited in June, 1992. Zalmac Mines proceeded to carry out a program of geological mapping, soil and rock sampling, surveying and aerial photograph studies of the general area around, and including, the Rampalo occurrence. Lineations identified by the aerial photograph study coincide with anomalous gold, silver and base metal soil geochemistry.
