The Quatsino Formation is a limestone sequence 60 to 250 metres thick that occupies a belt 3 kilometres wide extending northwest from Gillies Bay to Blubber Bay at the tip of Texada Island. It conformably overlies Karmutsen Formation volcanics and mainly comprises pure, massive to poorly bedded calcareous and dolomitic limestone. Both formations form part of the Upper Triassic Vancouver Group. Exposed contacts between the limestone and underlying volcanic rocks are usually marked by steep faults. The volcanic rocks comprise rhythmically layered amygdaloidal, feldspar porphyritic and spherulitic basalt flows. A major episode of folding (F1) has been recognized; this resulted in the limestones and, to a lesser degree, the underlying volcanics, being deformed into a series of broad, northwest trending open folds that plunge northwards. Two subparallel, northwest striking lineaments are evident in the area. The Ideal and Holly faults have apparently controlled the emplacement of some Jurassic intrusions and their associated skarn mineralization.

The Middle Jurassic Gillies stock intrudes both the Quatsino and Karmutsen formations. The stock has yielded a zircon U-Pb radiometric age of 178 Ma (Fieldwork 1989) and is genetically associated with several magnetite-rich skarn deposits (Prescott 092F 106, Lake 092F 259, Yellow Kid 092F 258 and Paxton) in an area 1524 by 609 metres. It mainly comprises a grey, medium-grained equigranular quartz monzonite that contains amphibole, biotite and occasional pyroxene phenocrysts. A late potassium feldspar rich phase is also present. The stock and the surrounding limestones are cut by sets of north and east trending feldspar porphyritic dykes that reach 10 metres in thickness and postdate skarn mineralization. The Gillies stock and its associated iron-skarn deposits lie close to the Ideal fault. Locally, at the iron mines (Prescott, Lake, Yellow Kid and Paxton), the volcanic-limestone contact is highly deformed and these structures have partly controlled the distribution of the magnetite ore. The Karmutsen volcanics in the vicinity of the Gillies stock are variably metamorphosed, most generally to a chloritized or epidotized basalt; the Quatsino limestone is bleached white and coarsely recrystallized.

Magnetite skarn mineralization at the Paxton mine is generally developed close to or along the eastern margin of the Gillies stock. Mineralization is concentrated along either the Quatsino-Karmutsen formations contact or the margin of the Gillies stock. Magnetite orebodies adjacent to the stock are generally associated with abundant garnet-pyroxene-amphibole skarn. The massive magnetite occurs with reddish-brown garnet, pyroxene (hedenbergite-diopside), epidote, amphibole (actinolite), minor calcite and sporadic chalcopyrite, pyrite and pyrrhotite. Traces of arsenopyrite and rare sphalerite are also observed (International Geological Congress Guidebook, Day 2-Texada, by A. Sutherland Brown). The skarn alteration and mineralization overprints all phases of the Gillies stock and, to a lesser degree, the limestone and volcanic rocks, although it is difficult to distinguish between exoskarn and endoskarn. The main ore mass appears to have formed in a wedge between the intrusion and the southwest dipping limestone-volcanic contact. High grade ore replaces either quartz monzonite or adjacent volcanic rock. Lower grade ore and skarn continues north as a subhorizontal tongue-like projection along the limestone-volcanic contact. The contact of skarn with volcanic rocks is generally gradational over several metres and only occasionally is sharp. In contrast, skarn always terminates abruptly against limestone. Mineralogical zoning is recognized in the main ore lens. The centre of the lens comprises coarse-grained massive magnetite relatively free of skarn and containing small pods of calcite mineralized with chalcopyrite and pyrite. Calcite veinlets project into the main mass of magnetite. The massive magnetite then grades in a mixed magnetite and skarn zone in which magnetite both veins and replaces skarn. Locally, chalcopyrite and pyrite occur close to the outer margins of the skarn envelope, adjacent to limestone or marble. Magnetite veinlets commonly cut garnet-pyroxene skarn. Early garnet-pyroxene assemblages were followed by the introduction of magnetite and late sulphide mineralization. In the southeast portion of the Paxton pit, thin stringers of molybdenite cut both skarn and quartz monzonite. A feldspar porphyry dyke 10 metres wide strikes through the northwest part of the pit. The ore at the Paxton mine contains a high copper content and concentrates produced from milling contain recoverable amounts of gold and silver.

The initial discoveries of the four main iron-skarn deposits were from west to east, the Prescott (092F 106), Yellow Kid (092F 258), Paxton and Lake (092F 259). Subsequent discoveries by underground exploration included the Midway and the Le Roi (combined with the Yellow Kid), Lake Extension (combined with the Lake) and Anomaly A (combined with the Prescott).

During the years 1885 to 1903, and 1908, 26,213 tonnes of magnetite ore were reported to be shipped from the Prescott deposit except for approximately 964 tonnes from the Lake deposit (092F 259). Sporadic activity continued until 1916; at that time the workings at the Prescott mine included a large quarry, shaft, an adit connected to the shaft and four working levels above the adit. No further activity was reported until 1952 when open pit operations began in earnest at the Lake, Paxton and Prescott deposits. Production figures from the Lake (092F 259) and Paxton mines are included with the Prescott (092F 106). The Yellow Kid deposit (092F 258) was discovered in 1953-1954; in 1955 an open pit operation started and in 1957 milling of magnetite ore began. Underground exploration began in 1959 in an adit driven from the shoreline to explore beneath the Prescott and Yellow Kid open pits. In the course of this underground development, the Midway deposit was discovered between the Prescott and Yellow Kid pits and production, beginning in 1964, is included with the Yellow Kid. A shaft and 5 levels were established to mine the deposits. A crosscut driven in 1964 to intersect the Lake Extension orebody (an extension of the Lake deposit), discovered another orebody, the Le Roi, which occurs between the Paxton and the Yellow Kid open pits. The Le Roi orebody, due to its proximity to the Yellow Kid deposit, has been included with the Yellow Kid. A decline was started in 1966 from the Lake open pit to mine the Le Roi and Lake Extension orebodies. By 1968 all open pit mining ceased. Some underground development work was done on the Anomaly A orebody in 1969-70, located 440 metres northwest of the Prescott open pit.

The Texada Mines, which encompassed all of the above deposits and orebodies, closed on December 17, 1976 due to exhaustion of ore reserves.

Consolidated Van Anda Gold Ltd. reported that its processing mill is now in place, and it has approval to process a 10,000-tonne bulk sample of magnetite from the Paxton pit. The mill will initially produce magnetite as a heavy medium for use in the coal industry; production was scheduled to commence in October 1997 to secure contract bids in January, 1998. The magnetite has also been successfully tested as a sandblasting abrasive (T. Schroeter, personal communication, 1997).

The mill, completed in 1998, will produce clean magnetite from skarn ore stockpiled by Texada Iron Mines in the 1960's. Consolidated Van Anda shipped a small amount of magnetite to the Quinsam Coal operation (092F 319).