Fibrous Minerals in the Wabush Iron Ore District, Labrador, Newfoundland Canada

Abstract

<p>Fibrous minerals are common in the highgrade, metamorphic, Precambrian Wabush Iron Formation, Labrador, Newfoundland, Canada. The most abundant fibres are amphiboles of the cummingtonite-grunerite series; mineralogical studies support the work of Klein (1960, 1964, 1966) and Chakraborty (1966). Iron ore mining and pelleting operations in the Labrador City are yield tailings containing many fibres (amphibole; iron and iron-manganese compounds) which find their way into the natural waterways. Water samples in Wabush Lake have fibre concentrations greater than 2 x 10⁹ per litre. Analysis of concentration and/or chemical composition of water, tailings, rock, bottom sediment, and soil samples identifies mine waste deposits as the major source of fibres. Comparisons between sediment inputs (and inputs of mineral fibres) from mining operations and natural weathering processes indicate the major impact of mine wastes. Calculations applying Stokes' Law of Settling to the fibrous minerals illustrate how the fibres settle out in Wabush Lake.</p>