POTENTIAL HAZARD MAP FOR THE WET MUCK FLOW PREVENTION AT THE DEEP ORE ZONE (DOZ) BLOCK CAVE MINE, PAPUA, INDONESIA

The Deep Ore Zone (DOZ) Block Cave Mine lies at Tembagapura (Papua), one of the third lift of block cave mines in the East Ertsberg Skarn System (EESS) after the Gunung Bijih Timur (GBT) Surface Mine and the Intermediate Ore Zone (IOZ) Block Cave Mine. This mine is an underground mine that utilizes the gravity flow system and has produced about 150 million tons of ore with 1.06% Cu and 0.81 ppm Au, operated since 2000 with production was about 58k tons/day and production is being ramped up to 80k tons/day by the end of 2009 until now. The increase of production arose various challenges and the most dangerous one is the wet muck flow. Potential impact of the wet muck flow is relative to fatality and economic loss. There are three main aspects that influencing the wet muck flow formation, such as wet muck material forming, triggering mechanisms, and wet muck flow potential. Conditions of the wet muck material forming are analyzed from drawpoints mapping and water balance data from the Underground Geology and Hydrology, there are fine grain (grain size 5cm, loose grain (less than 90% optimum density), and saturated or near saturated (80%). In addition, the high intensity of rainfall at the active mining area influences the wet muck material forming. Triggering mechanisms are caused by mining activities such as mucking and blasting, analyzed based on the Engineering Cave Management data. The combination of both aspects show the wet muck flow potential that summarize into a potential hazard map. The potential hazard map is calculated and divided into high, medium and low risk. The calculation will combined with status of drawpoints and showed the wet muck flow potential area in 2D map. This map will help the Operation to see the concern area of mucking pattern for preventing the potential impact of the wet muck flow.