On 22 June 2020, good news came from Huijin Project that a successful breakthrough between air intake shaft and service shaft on -1000mL at Shaling Gold Mine was achieved with a horizontal error of 58mm and vertical error of 36mm.
The air intake shaft is designed with net diameter of 6.5 meters and a depth of 1350 meters, while service shaft with net diameter of 8.2 meters and a depth of 1560 meters. After sinking down to 1000m at both shafts in May, more challenges emerged as technically that’s where ultra-deep shaft sinking commenced. In order to better facilitate power supply, drainage, and ventilation below -1000mL, JCHX proposed to construct a connection drift between two shafts on -1000mL, which was accepted by the client as additional works post mutual discussion. This successful breakthrough should largely improve underground working conditions especially in deep zone.
The connection drift on -1000mL between two shafts was merely 202m long, despite of such short distance both JCHX team and the Client paid close attention to the work, for it is the first breakthrough between two shafts at Shaling Gold Mine.
In order to ensure the safe and precise breakthrough, surveyors made specific technical proposals, engineers reviewed original surveying data many times and gave instructions on site. Mr. Gao Changbao, survey supervisor and senior engineer, paid two site visits to conduct gyrostatic orientation survey. A survey supervisor from JCHX Central South Branch was assigned to site for completing setting-out work. Close cooperation among these technicians ensured final successful breakthrough.
Following the breakthrough, upgrading and optimization to the power supply and drainage systems shall be done to create better conditions for efficient sinking of two shafts in deep zone and to ensure key timelines are kept.