The following are the biggest percentage gainers on the TSX Venture Exchange in mid afternoon trading with their price movements SIERRA IRON ORE (NAA.V), $0.40, +0.11, +37.93% YOHO RESOURCES (YO.V), $0.24, +0.05, +26.32% BCM RESOURCES (B.V), $0.20, +0.04, +25.00%