Miners known as Developers worked in pairs to drill a pattern of holes into the tunnel face using drills powered by compressed-air.
Two machine men or 'developers' worked together to drill a pattern of holes into the face of the tunnel. The holes were then charged with blasting gelatine - a powerful explosive - and fired with electric detonators. This would extend the tunnels underground to reach and follow the lode. Developers could extend tunnels at a rate of about 2.4 metres (8 feet) per day.