The Monteith Bay geyserite deposit is located near shore on the western side of Monteith Bay, south western Kashutl Inlet.

The deposit consists mainly of replacement silica in a concentration greater than 96 per cent SiO2. It is a paleo-hotsprings deposit of massive thickness, originally of gently dipping bedding, now somewhat faulted, bent and dipping to the south about 40 to 50 degrees.

The volcanic host rocks in the Monteith Bay area consist of hornblende-plagioclase porphyritic andesite, amygdaloidal flows and flow breccias of the Lower Jurassic Bonanza Group. Late intrusive rocks occur as fine-grained porphyritic andesite dikes and sills.

The rocks are altered to various degrees, with silicic and advanced argillic zones present. The lack of structural control, of associated large intrusions and overall distribution of the alteration assemblages suggest that the silicification took place contemporaneously with volcanism before significant structural dislocation. The sericite-rich alteration in Monteith Bay appears to correlate directly with the emplacement and shearing of the later andesite dikes. The presence of chalcedonic silica, alunite and pyrophyllite indicate a probable near surface origin for the main phase of alteration.

Diamond drilling demonstrates the continuity and purity of the geyserite material (geyserite is a synonym of siliceous sinter). A typical analysis of geyserite for major elements is as follows: 1.02% Al2O3, 0.13% CaO, <0.01% Cr2O3, 0.34% Fe2O3, 0.26% K2O, 0.04% MgO, <0.01% MnO, 0.05% Na2O, 0.09% P2O5, 95.6% SiO2, 0.24% TiO2 and 2.0% LOI. Volume calculations on cross-sections spaced 20 metres apart give a preliminary reserve of 1,814,200 tonnes of pure geyserite. (Prospectus, New Global Resources Ltd., September 1993).

Silica, one of the minor constituents of Portland cement manufactured by the Tilbury plant in Delta, is to be supplied from the Monteith Bay geyserite property.

The claims covering the geyserite were staked in 1908. Nearby pyrophyllite deposits provided material for fire clay, pipe and other industrial uses for the B.C. Pottery Company and the San Juan Mining and Manufacturing Company from 1910 onward.

Comprehensive mapping of the deposits was completed in 19 13 by C. H. Clapp of the Geological Survey of Canada.

In 1952, the Crown-granted claims were purchased by St. Eugene Mining Corporation, who subsequently optioned the property to Westport Chemical Inc. during 1959/60. Drill testing was completed on the alunite-pyrophylIite zone.

Two packsack holes were drilled to a depth of 25 feet in the alunite area by Falconbridge Nickel Mines, who acquired the property from St. Eugene in 1962.

The Kyuquot syndicate was formed in 1970 as a joint venture between Falconbridge and MacDonald Consultants Inc. to explore the area for porphyry copper deposits. Mapping and soil sampling were completed near Easy Inlet.

Kennco Exploration staked claims over the Kayouk Peninsula-Jansen Lake area in 1972 and completed geological mapping and a rock geochemical survey.

The B.C. Gold Syndicate explored the Easy claims in 1980 by prospecting, soil-sampling and geological mapping to better evaluated the intense alteration zones as defined by the areas of pyrophyllite-alunite.

Semco completed an examination of the Falconbridge property and Easy Inlet areas in 1980 as part of a program on three pyrophyllite occurrences in the area. A preliminary report for Falconbridge Nickel Mines Ltd. was completed by in 1982 covering historical, exploratory and geological data from past examinations and including geological mapping and geochemical sampling as completed in 1982.

In 1983, Falconbridge, completed 1,066 metres of diamond drilling in seven holes in joint venture with Cal Denver Resources Ltd., on the northern tip of the peninsula. Detailed mineralogical and petrographic studies on the drill core delineated two recognizable alteration zones: (1) a quartz, alunite, pyrophylhte, kaolinite zone to a depth of approximately 140 metres below sea level (low pH zone) and (2) a gypsum with lesser anhydride zone below. An airborne geophysical survey of 128 line-kilometres was carried out in 1985.

Monteith Bay Resources Ltd. initiated the purchase of the Too Easy claim in 1992 and completed detail geological mapping and sampling in November 1992 to January 1993. Accurate topographic surveying, hydrographic survey of Monteith Bay, biological study of the area and detail diamond-drilling were done between January and March 1993. A 9,000 tonne bulk sample and further diamond drilling was done between March and July 1993. The cement plant processed the geyserite during August and September 1993.

In 1995, Monteith Bay Resources Limited received a certificate to produce "geyserite" silica from a seasonal quarry on East Inlet. The quarry is permitted to produce up to 100 000 tonnes per year, but it is not yet in production. In 1998, Tilbury Cement Limited bought the property and prepared it for production. It expects to make its first shipment of approximately 30 000 tonnes in 1999. Construction Aggregates plan production in 1999.

New Global Resources Ltd. received a Mine Development Certificate in 1995. It has applied for permits to extract a 10,000-tonne sample of creamy-white, compact, soapy pyrophyllite from an old quarry a few hundred metres south of Monteith Bay silica deposit.

The Monteith Bay geyserite quarry started commercial production in 1999, providing high grade silica rock to the Tilbury cement plant in Delta. Approximately 120,000 tonnes were mined to the end of 2001 (Assessment Report 26824). In 2002, Monteith Bay Resources Ltd. (an affiliate of Lehigh Northwest Cement Ltd.) produced and barged 43,199 tonnes of hotspring silica from its quarry (Exploration and Mining in BC 2002, page 34). During 2003, Lehigh Northwest Cement Limited (formerly Tilbury Cement Ltd.) mined 51,000 tonnes of geyserite to supply its cement plant in Delta (Exploration and Mining in BC 2003, page 61). In 2005 Lehigh produced 29,500 tonnes from its quarry. This operation was inactive in 2004 Delta (Exploration and Mining in BC 2005, page 81).

The recovered amount of silica has not been published.

In 2006 Lehigh produced 30,500 tonnes geyserite (Exploration and Mining in BC 2006, page 93). In 2007, 2008, and 2009 the quarry remained on care and maintenance (Exploration and Mining 2007, 2008, 2009). In 2012, Homegold Resources completed a ground magnetometer survey on the area of the former quarry. During 2015 through 2019, Homegold Resources Ltd. completed minor programs of rock sampling on the area as the Monteith Bay Pyrophyllite property.

See also Morris (MINFILE 092L 072), At Monteith (MINFILE 092L 117), Sockeye (MINFILE 092L 246) and Sic (MINFILE 092L 276).