At the stage of detailed exploration the area of the open pit is drilled by core holes to the full depth of mineralization on a network of 100X50 m (100X75 m - in the plane of dip of the ore body). At the stage of operational exploration - to a depth of 30-40 m using a 50х25 m grid (50X40 m in the plane of the ore body dip). The 50X25 m grid is used to drill the central part of the pit, where mainly rich and poor ores are concentrated. The hanging and lying sides of the ore deposit (poor ores and ore-free interlayers) were explored using a 100X50 m grid. Exploration boreholes were sampled within the ore deposit section by section, with section length of 2-3 m. Samples were analyzed for iron, sulfur and phosphorus. Blast holes 10-20 m deep were drilled on a 6X6 m grid, sampled with one sample and analyzed for iron and sulfur.