On 30 Mar 2020, Wu Xuchun, GM of Hainan Mining Co., Ltd paid a visit to Haikuang Project along with a delegation, to congratulate JCHX for its successful reconstruction of 2# Ore Pass ahead of schedule.
Project Management lead by PM Wang Hongqin extended sincere welcome to the guests. Both parties had warm discussions in the meeting room, where GM Wu officially extended his earnest congratulations, and probed into further improvement for future production. PM Wang delivered a specific report on safety production, labor organization, technical support, equipment operation, and logistic services. Subsequent production schedule, improvement measures and overall planning were also confirmed, which laid a solid foundation for the completion of annual target and future extension of cooperation.
2# Ore Pass (sublevel -120m to -480m) was put into use from May 2017, with designed capacity of 3.8mtpa. However significantly increased amount of bulk waste rocks was identified in May 2019 with root cause analysis showing that sectional collapse occurred due to worn-out and unstable sidewall on -151m.
Following which the Client required JCHX to reconstruct and reinforce the ore pass. Upon receiving the instruction, team on site immediately made plans and started to mobilize manpower, materials and equipment, facilitating the commencement of reconstruction from 5 June 2019.
According to the design and site situation, support method comprising of double-layer reinforced concrete with manganese steel plate between -151m to -176m, and fibercrete lining from -176m to -207m was applied. Totally 5,669 bolts of various dimensions (2m, 2.5m. 3m, and 5m), and 1,186 pieces of 1.5mX2m meshes were installed, with shotcreting quantity of 512m³, concrete lining of 7,187m³, and 590t of steel structures such as rebar, H steel, steel fiber, and manganese steel plate.
All members on site worked together to overcame multiple challenges to ensure the successful reconstruction of 2# Ore Pass. 1. Materials required for ore pass reconstruction need to be transported via a crosscut at -120m, coincidently it was also a key way for ore transportation, during reconstruction, material and ore transportation were completed without interfering each other through well coordination.
2. Due to extremely poor ground condition, and a maximum exposure of 300㎡, high safety risks and great challenges were encountered with sectional collapses happened frequently. Being aware of the situation, PM Wang took the lead to check construction site, and suggested the application of 5m rock bolts as well as additional shotcreting, which successfully increased the stability of collapsed section and ensured safe and rapid concrete lining.
3. the progress of concrete lining was postponed due to limitation of work area, JCHX team on site suggested the application of two relayed concrete pumps to cover 500m of pumping. Through this approach, a daily concrete lining volume of 260m³ was achieved, breaking record.
Client declared at the end of November 2019 that the deadline for completing ore pass reconstruction was 20 Jan 2020. All reinforcement and reconstruction works were completed with good quality and safety on 9 Jan, temporary facilities were dismantled with permanent facilities recommissioned on 17 Jan, enabling the restoration of production in Feb. In March the daily output reached 15,720 tons, higher than the targeted daily output.
After the meeting, GM Wu presented a silk banner as an honor to JCHX, and group picture was taken to memorize this historical moment.
