The Highland Surprise consists of a group of old Reverted Crown grants situated between Whitewater Creek and the headwaters of Lyle Creek, some 28 kilometres northwest of Kaslo, British Columbia. The Fletcher and Phoenix Reverted Crown grants comprise the main two of eight with extensive workings that produced 1903 tonnes of ore from 1938 to 1942. Excellent detailed descriptions of the workings and associated mineralized quartz veins are provided in Minister of Mines Annual Report 1937 and Bulletin 7.
The main lithologies of the area are assigned to the Permian Kaslo Group, consisting of andesite flows, pyroclastics and tuffaceous sediments. Volcanics are extensively chlorite altered and schistose. Underground workings at the Highland Surprise provide one of the best locations for pyroclastic and sedimentary textures in the area. The volcanics and sediments are generally oriented 320 degrees and the contact between these two units has a strike of 350 degrees. Sediments and volcanics have been intruded by a granitic dike, exposed on the No. 1 and No. 2 levels. The dike appears to increase in size with depth and outcrops to the east of the workings. Serpentinite is the most extensive rock type exposed in this area, forming northwesterly trending bands with steep southwest dips and extending up to 750 metres in width. Talc and asbestos are common alteration minerals associated with this serpentinite unit. The contact between the serpentinite and surrounding lithologies is faulted. This faulted contact has a strike of 350 degrees and a steep westerly dip. The surface trace of this fault can be traced for several kilometres. Underground, this fault is marked by a heavy talc gouge. Dikes and sills in the area are dioritic and feldspar porphyry dikes are common.
Veins at the Highland Surprise occurrence are of two types, both fracture hosted in Kaslo Group greenstone adjacent to serpentinite. One type has a quartz and calcite gangue containing auriferous sulphides, principally pyrite and chalcopyrite with minor amounts of sphalerite, galena and a little free gold, and the other veinlets in shear fractures consisting of quartz and albite. Pyrite is sparsely disseminated in the quartz, albite and adjacent greenstone wallrock. The two types may be found to occupy the same fracture along strike. Mineralization is foliation parallel, however, the zone swings east where the serpentinite body is intersected.
Underground workings at the Highland Surprise occurrence follow the contact between serpentinite and veins and feldspar porphyry dikes. Veins have extremely irregular contacts and pinch and swell from a stringer to within one-half metre and change dips as much as 90 degrees. Briefly, the workings consisted of three adits, the 100, 110 and 120 levels at 1667, 1706 and 1663 metres elevation respectively. See Bulletin 7, Figure 4 for a detailed plan-view drawing of underground workings. The original surface exposure consisted of a 60 centimetre wide quartz vein in sheared greenstone. The vein strikes 335 degrees and dips 90 degrees northeast and is sparsely mineralized with pyrite and chalcopyrite. The vein is traceable on surface for some 45 metres.
By 1940, the 100 level produced 94 tonnes containing 2034 grams silver and 2668 grams gold (Bulletin 7). Production records for other stopes on the 110 and 120 levels are also provided (Bulletin 7). Total production amounted to 1903 tonnes containing 50,947 grams gold, 29,765 grams silver, 145 kilograms lead and 145 kilograms zinc over its 5 year life. Most of this ore was treated at the Whitewater mill or shipped directly to the Trail smelter. Up to 1942, a total of 990 metres of underground work and 231 metres diamond drilling was done on four adit levels.
In the 1970s, this property was re-examined by MCP Resources Corp. Chip samples taken across the vein structure showed significant gold and silver values. Sample No. 1 analysed 33.06 grams per tonne gold and 4.98 grams per tonne silver; sample No. 3A of dump material yielded 34.19 grams per tonne gold and 19.84 grams per tonne gold. Plans were made to begin shipment of selected mineralization on a 18,144-tonne dump (George Cross News Letter No.210, October 31, 1979).
The area surrounding the Highland Surprise was explored again in 1987 with several rock samples yielding significant results. Sample MR-8 was sampled across 0.5 metre of a quartz vein hosted in sheared andesite. The strike of the vein is 145 degrees dipping vertical. The average width of the vein is 45 centimetres. The orientation of the vein is irregular and it pinches and swells over its exposed length. Assay results yielded 15.36 grams per tonne gold and 6.7 grams per tonne silver (Assessment Report 19475). A second sample, Sample MR-11, yielded 54.8 grams per tonne gold and 44.0 grams per tonne silver. This sample was a grab sample of the best looking quartz vein material, hosting up to 5 per cent sulphides consisting of pyrite, chalcopyrite, magnetite and sphalerite? with little or no carbonate. Similarly, samples SH-4 and SH-5 yielded anomalous assay results of a quartz-carbonate vein with disseminated pyrite and minor chalcopyrite (Assessment Report 19475).
