Dr. David R S Thomson - Cia. Minera Catedral - Santiago, Chile.

SUMMARY.
     The large tonnage of easily mined high grade limestone, the strategic location, the nearby gas line, as well as the shortage of suitable and accessible limestone in Chile, strongly favour a lime producing operation at Catedral. The market study undertaken for SAGC’s new Quellon lime operation, shows there is a market opportunity in which the expected low cost and volume of lime production at Catedral could result in a very competitive lime producer.

GEOLOGY.
    The Catedral Project is located 80 km in a direct line south east of Santiago. The distance by road from Santiago is 110 km, with travel time taking approximately two hours. The last 48 km are unpaved.

    The limestone belt in the project area corresponds to the upper part of the over 200 meter thick Cretaceous LoValdes Formation. The limestone beds dip steeply and are on the western limb of a broad anticline, which strikes 10 to 15 degrees north west and plunges gently towards the south. The extension of the limestone to the north is truncated from the younger sediments of the Colimapu Formation by a strong N60E trending fault zone. A kilometre south of this break, a massive N30W fault called the Mona fault has distorted the limestone beds forming a zone up to 200 meters wide. From this point towards the south, the limestone formation is unaffected by large breaks. It extends for 6 km before passing out of Cia. Minera Catedral’s claims at an altitude of 3800 meters. In all, there are 8 km of LoValdez Formation limestone beds within the company claims.

    At the northern end of the limestone belt and up to an altitude of 2300 meters, the rocks are largely covered by deposits of glacial origin. Good rock exposures occur to the south above 2700 meters. On the north-west trending Mona Ridge, there are good exposures of limestone over a length of 600 meters and a width of up to 150 meters (photo 3). This ridge lies parallel and immediately to the north of the strong Mona fault referred to previously. Limestone exposures on the extension of the belt to the south, beyond the influence of the N30W fault zone, start 500 meters south of Mona Ridge at an altitude of 2750 meters. At this point the limestone is 215 meters thick.

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