On February 2, 2022, a precise and long-distance breakthrough was achieved by JCHX between the service decline and 1# shaft on -200mL at Cukaru-Peki Copper & Gold Mine in Serbia for Zijin Group, following the successful breakthrough between the service decline and 2# shaft on -80mL achieved earlier on November 17, 2020, indicating that Kinsey project has made remarkable headway regarding the fulfillment of 2022 production and excavation target.
Development on -200mL is the critical path for annual production target of Cukaru-Peki mine. The production target for the areas below -80mL (-160mL and -200mL) accounts for 49% of the annual target for 2022, which is a bit challenging, especially considering the fracture zone.
In order to successfully pass fracture zone and reach -200mL, after proactively communicating with the Owner, an optimal technical proposal was prepared which include the application of grouting, fore-poling, steel arches and installation of bolt + mesh + shotcreting at FOG areas.
Work was progressed efficiently with 16 steel arches and application of bolt + mesh + shotcreting completed as scheduled. In view of the poor stability of wall rock after passing FOG areas, the project then decided to execute works based on the principle of applying support immediately after excavation and advance slowly but surely to maintain the stability. Therefore, the advance footage per cycle was controlled within 2.5m, cover drilling was conducted every 4 blasts, and 1 blast per day was basically guaranteed.
The advance footage reached back to 3.5m per cycle when only 45m was left before breakthrough. Besides, the construction speed was accelerated when the mucking distance was 3600m and whole-section bolts + meshes + shotcreting support method was applied, during which a record of 3 blasts in 2 days was achieved.
When the service decline was developed to the critical point for the breakthrough, various measures were taken to motivate workers and improve work efficiency, such as optimizing work organizations and assigning specific personnel and fleet to specific working areas. Besides, construction methods were adjusted accordingly based on geological conditions, so as to ensure unhindered work progress and fully prepare for the development of the service decline under more challenging conditions below -200mL.
