IMG_1580, originally uploaded by Mic2006.
At Bear Lake the exposed centers of the dykes are composed of salmon coloured calcites that have been impregnated by large apatite spikes and titinite crystals (more on titinite later). Some apatites have grown to several inches in length – the occasional piece can exceed two or three feet, but those once-in-a-lifetime monsters are rare. They lie only in the deepest trenches.
Books of biotite mica and crystals of feldspar and hornblende cluster on the overhanging trench walls. They are like a jumbled box of greasy black lego pieces; a great profusion of fused blocks and prisms that drop down along the rocky walls deep into the dirt. It is very difficult to work them free and the impediments are multiplied by the size of the holes. Some are so tight that it is impossible to use a hammer and chisel.
In the late 19th century apatite was the chief source of phosphate for fertilizers. 1870 marks the first recorded commercial shipment of that mineral from Ontario. The load was extracted from a deposit in North Burgess Township.
Apatite is most abundant in Lanark, Leeds and Frontenac Counties in Northeastern Ontario. There are also many good deposits around the Gatineau and Lievre Rivers in Quebec. In the Rideau area there are over twenty small abandoned pits. The largest of those mines was the Opinicon Mine. It was worked between 1888 and 1892. Most mining around Ottawa was conducted on a relatively small scale where farmers made ends meet by working local pits in the winter instead of pursuing the more traditional winter lumbering practices.
Ontario’s small farm/mine industries quickly died with the establishment of the Southern guano industry but it was only a temporary setback because the pegmatite dykes that contained apatite were also rich in other minerals. A pit that had begun as a source of apatite often went through several cycles of mineralogical rebirth, an abandoned phosphate pit often re-emerging as a mica mine in the early 1900’s, later, as a feldspar pit in the 1920’s and if the owners were lucky, as a source of radioactive ores in the 1950’s.
The Sand Lake Mine, from where 15 tons of apatite was exported to Germany in the 1870’s now sits forgotten in amongst the tangled forest near Ottawa. It is a putrid, black, pool about twenty-five feet wide and said by locals to drop to a depth of 75 feet. It is clogged with sticks and pond slime. This is one of the several pits associated with the better-known “McLaren Mine”. In 1900 the Brockville Mining Company acquired the property for its alternately appearing deposit of phylogopite mica. The mineral occurs in a chimney deposit that runs through pyroxenite and biotite gneiss. The property was mined intermittently from 1905 through to 1907 and from then, on an irregular basis, through to 1916. This is the typical phoenix like nature of the small Ottawa area mines, to all appearances dying and then, unexpectedly reviving with some new use of its mineral abundance.
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