At the stage of detailed exploration, the area of the open pit was drilled by core holes to the full depth of mineralization on a grid of 100×50 m (100×75 m in the plane of dip of the ore body). At the stage of operational exploration, it was drilled to a depth of 30–40 m on a 50×25 m grid (50×40 m in the plane of dip of the ore body). The 50×25 m grid was used to drill the central part of the pit, where mainly rich and poor ores are concentrated. The hanging and foot walls of the ore body (poor ores and barren interlayers) were explored on a 100×50 m grid. Exploration boreholes were sampled within the ore body in sections, with a section length of 2–3 m. Samples were analyzed for iron, sulfur, and phosphorus. Blast holes 10–20 m deep were drilled on a 6×6 m grid, sampled as one sample, and analyzed for iron and sulfur.