The Jericho 1 (Adit) occurrence is located on the western arm of Moly Creek, a small north-flowing tributary of Witches Brook, and immediately north east of the Highmont tailings dam.
The area is situated on the eastern flank of the Lower Jurassic Guichon Creek Batholith and is underlain by Guichon-variety rocks of the older Highland Valley phase of the batholith. These rocks are medium- to coarse-grained, creamy grey-pink–coloured granodiorite to quartz diorite, rich in biotite and plagioclase. Foliation strikes 305 degrees. Intense sericite, chlorite and clay alteration is associated with -northeast striking and north-dipping fault zones that host mineralized quartz veins.
The No. 1 zone consists of mineralized quartz veins and/or tension fractures, up to 15 centimetres wide, in the hanging wall of a fault striking north 62 degrees east and dips 63 to 65 degrees north-west. The veins and fractures trend north 30 to 60 degrees west and dip 60 to 70 degrees north-east. The principal sulphides are bornite associated with primary chalcocite, chalcopyrite and seams and disseminations of molybdenite. The vein walls are sheared with chlorite, sericite, potassium feldspar and zeolite alteration. The zone strikes west to north-west, while the similarly mineralized 890 and 1725 zones trend east-north-east. The No. 1 zone has been traced by diamond drilling over a length of 84 metres along strike, a width of 9 metres and to a depth of at least 135 metres below the lower adit, whereas the 1725 zone has been traced for a length of at least 93 metres, to a depth of 30 metres below the lower adit and averages 1.5 to 2.1 metres in width.
In 1963, diamond drilling intercepted a altered porphyry dike that hosts disseminated bornite and chalcopyrite mineralization yielding an estimated grade of 1.5 per cent copper over 17.7 metres in hole no. 6, 1.5 per cent copper over 5.1 metres in hole no. 1 and 0.75 per cent copper over 4.2 metres in hole no. 3 (Property File - Sirola, W.M. [1963-12-20]: Correspondence re: Jericho Mines).
In 1964, drilling indicated a zone approximately 45 metres long and 6 metres wide averaging 1.44 per cent copper (Property File - Stephen, J.C. [1964-06-22]: Correspondence Re: Jericho Mines current exploration - Highland Valley area). Other reports indicate that test holing on the no. 1 zone from the upper adit yielded 1.50 per cent copper over a length of 84 metres and a width of 9 metres, whereas assays from a 42- metre long drift on the 1725 zone averaged 1.50 per cent copper over a width of 2.1 metres (Property File - Phendler, R.W. [1970-07-09]: Report on the properties of - Jericho Mines Ltd. and Gaza Mines Ltd. - Highland Valley, British Columbia - for Alwin Mining Company Ltd.). A possible reserve of 160 ,790 tonnes grading 1.93 per cent copper was reported at this time (Property File - Phendler, R.W. [1970-07-09]: Report on the properties of - Jericho Mines Ltd. and Gaza Mines Ltd. - Highland Valley, British Columbia - for Alwin Mining Company Ltd.).
In 1965, sampling of the 890 zone from the lower adit yielded 1.0 per cent copper over 1.35 metres and 0.80 per cent copper over 2.7 metres, whereas sampling of the 1725 zone yielded 1.19 per cent copper over 3.0 metres (Property File - Jericho Mines Ltd. [1965-06-01]: Progress Report to May 31st, 1965). An indicated resource for the No. 1 zone, to a depth of 139.5 metres, of 235,870 tonnes grading 1.5 per cent copper was reported (Property File - Jericho Mines Ltd. [1965-06-01]: Progress Report to May 31st, 1965). Later in 1965, a probable ore resource of 235,870 tonnes was reported for the No. 1 zone, with 181,440 and 45,360 tonnes of indicated ore in the 1725 and 890 zones, respectively, all grading from 1.5 to 1.6 per cent copper (Property File - Jericho Mines Ltd. [1965-11-22]: Summary Report for the Period November 1964 to November 1965 - Jericho).
In 1968 and 1969, drilling yielded intercepts of 0.55 per cent copper over 45.15 metres in hole no. 7, 0.77 per cent copper over 57.6 metres in hole no. 9 and 0.40 per cent copper over 29.1 metres in holes no. 10, and surface sampling of trenches yielded from trace to 0.63 per cent copper over 1.2 to 2.4 metres (Property File - Tremar Minerals Ltd. [1969-05-12]: Drill Hole Sections and Trench Plans - 1968 and 1969 - Jericho).
In 1970, underground sampling of the upper adit of the No. 1 zone identified four mineralized zones averaging 0.60 per cent copper over 9.3 square metres, 1.16 per cent copper over 204.4 square metres, 0.47 per cent copper over 55.7 square metres and 1.27 per cent copper over 752.5 square metres (Property Plan - Tremar Mines Ltd. [1971-01-22]: Assay and Geology Plan - Upper Adit - Jericho Property). Sampling of the lower adit of the No.1 zone averaged 1.10 per cent copper over a width of 1.35 metres and a length of 6 metres (Property File - Tremar Mines Ltd. [1971-01-21]: Assay Plan - Lower Adit - Jericho Property). A drill hole (513), which intersected the No. 1 zone 135 metres below the lower adit, yielded 0.39 per cent copper over 1.95 metres (Property File - Phendler, R.W. [1970-07-09]: Report on the properties of - Jericho Mines Ltd. and Gaza Mines Ltd. - Highland Valley, British Columbia - for Alwin Mining Company Ltd.). Sampling and drilling from lower adit of the 1725 zone yielded an average of 1.60 per cent copper over a width of 1.5 to 2.1 metres and a length of 96 metres, and drilling on the 890 zone yielded up to 1.05 per cent copper over 1.53 metres in hole 506 (Property File - Tremar Mines Ltd. [1971-01-21]: Assay Plan - Lower Adit - Jericho Property).
Also, at this time surface drill holes, located to the south east, intersected another mineralized zone, averaging from 0.6 to 0.9 metres wide. The zone strikes south west and north east and has been traced by diamond drilling for greater than 100 metres along strike. Drilling yielded intercepts from 0.20 per cent copper over 0.81 metre to 9.50 per cent copper over 0.21 metre (Property File - Tremar Mines Ltd. [1971-01-21]: Composite Plan - Surface DDH's, Induced Polarization, Underground Workings - Jericho Property)
In 1971, a possible ore estimate from nine ‘ore’ blocks of 283,900 tonnes grading 1.06 per cent copper was reported (Property File - Tremar Mines Ltd. [1971-01-25]: Vertical Sections - Jericho Property).
In 1977, approximate (indicated) reserves were reported at 272,130 tonnes grading 1.0 per cent copper (Property File - Highmont Mining Corporation : Annual Report 1977).
In 1979, drilling (hole J-79-11) yielded up to 1.76 per cent copper over 3.50 metres (Assessment Report 7756).
The mineralization was discovered in 1956 and subsequently developed by two adits. The upper adit, located on a low ridge, was driven 269.4 metres at a bearing of 084 degrees. The adit intersects mineralized quartz veins starting approximately 45.7 metres from the portal. From 190 metres to its end, the upper adit intersects the No. 1 zone. The lower adit was driven in a south direction and intersected the 890, 1725 and No. 1 zones at 267, 525 and 685 metres from the adit portal, respectively. Minor drifting was performed on the 1725 and No. 1 zones.
In 1962, Jericho Mines completed a 6.1 line-kilometre induced polarization survey on the area. The following year, 12 diamond drill holes, totalling 910.8 metres, were completed. In 1964 and 1965, a program including geological mapping, test hole sampling of the upper adit and at least 33 diamond drill holes, totalling 4097.7 metres, was completed. In 1966, Canadian Superior Exploration Ltd. and Jericho Mines Ltd. completed a program of silt and soil sampling, geological mapping, trenching and a 57.6 line-kilometre induced polarization survey on the area. During 1968 through 1970, Tremar Mines completed exploration programs including underground sampling, diamond drilling and a 50.5 line-kilometre induced polarization survey. In 1971, Highmont Mining Corp. optioned the property and completed 17 diamond drill holes, totalling 2538 metres, and 30 percussion drill holes, totalling 2926 metres. In 1972, a program of geological mapping, an induced polarization survey, six trenches, five percussion drill holes and three diamond drill holes were completed on the property. In 1979, Highmont Operating Corp. completed a drilling program including 2 churn drill holes, totalling 174.0 metres, 11 percussion drill holes, totalling 165.0 metres, 2 rotary drill holes, totalling 134.0 metres and 5 diamond drill holes totalling 504.0 metres, on the Gaza and Jericho claims. In 1980, a further three rotary drill holes, totalling 56.4 metres were completed. In 1981, 11 rotary drill holes, totalling 87.8 metres, were completed.