The Lake Cinch deposit occurs in Tazin gneisses on the footwall side of the Black Bay fault. Ore is localized by the Main Ore and the Crackingstone River faults. The Crackingstone River fault is barren, has an easterly strike and dips 80° south. The Main Ore fault strikes northeasterly, dips 50° to the southeast and abuts the footwall of the Crackingstone River fault. Ore also occurs in tension fractures striking northwest and dipping southwest, straddling the trough between the two faults. The Main Ore fault, Crackingstone River fault, and the tension fractures are a connate system. The Crackingstone River fault is thought to be a wrench fault, while the Main Ore fault is considered to be essentially a thrust fault. The block of ground between the Main Ore fault and Crackingstone River fault is interpreted as a small horst.

Pitchblende is the principal radioactive mineral of the deposit. It is intimately associated with hematite and occurs in calcite gangue. X-ray diffraction patterns of six samples of pitchblende were found to be poor to absent. This has been shown to be the direct result of a small particle size of the order of 2.2 x 10^-8 cm. A sample of pitchblende taken from the Eldorado property and studied for comparison was found to have a particle size of 2.2 x 10^-7 cm. This fine state of subdivision is apparently inherent in the method of formation of pitchblende from alkaline carbonate solutions.

The intimate association of pitchblende with earthy hematite was investigated by X-ray fluorescence analysis of seventy samples. It has been found that the iron content of the ore is directly proportional to the uranium contents up to 0.25%U, and thereafter it remains constant. Such a relation indicates a catalytic relation between the two elements.

Uranium is believed to have been transported in the hexavalent state as the uranyl tricarbonate ion [UO₂ (CO₃)₃]^-4, and deposited as pitchblende due to a decrease in pressure. The uranyl tricarbonate ion was reduced to pitchblende by ferrous iron which was oxidized to the ferric state to form hematite. The oxidation potential and pH considerations indicate that pitchblende could have formed under reducing conditions in a slightly acid to basic environment.

Pressure of formation of the deposit has been estimated as 160 atmospheres and the termperature is thought to have been 250°C. Thus the deposit belongs to Lindgren's mesothermal class.

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