M E M O R A N D U M 1 To: MTS UG From: Date: 10/01/2013 Subject: The new Water Risk Matrix and Water Zones at EHM Water Risk Matrix for EHM Purpose This memo summarises the changes that have been made to underground water management through the introduction of the Water Risk Matrix and the creation of 8 Water Risk Zones. Part 1 of this memo outlines how to use the newly introduced water risk matrix. Part 2 of this memo describes the 8 zones in detail and gives a background on the data that was used to define the zones. Summary A water risk matrix has been created for the EHM underground mine, which allows rating the likelihood and consequence of water intersects. In conjunction with the risk matrix the underground mine was divided into eight water zones, which represent different hydraulic characteristics and hence different likelihoods of water intersects. The consequence of water intersects is based on the effective pressure, which is calculated from the level pressure in each water zone and a flow factor. Level pressures and flow factors for each zone are given in a water pressure table. The level pressure table will be updated monthly and the date of the latest update will be indicated on the table. Part 1: Using the Water Risk Matrix The Water Risk Matrix and the Water Pressure Table for January 2013 are shown in Figure 1. An example of the water zones within the mine is given in Figure 2 for Levels 1600, 1325 and 1175. A summary of the water zones for all levels is given in Appendix 1. To use the Risk Matrix: 1. Determine which zone the development is taken place it. 2. Determine the likelihood for water intersects based on the water zone (see left of risk matrix). 3. Than refer to the Water Pressure Table to determine the water level pressure for the development level and zone. 4. Calculate the effective pressure and determine the Consequence of the water intersects. 5. Determine your water risk and proceed with the recommended level of precaution. In the absence of the water management matrix (which is presently being created), red and yellow risk ratings indicate current water cover precautions.
RkJQdWJsaXNoZXIy MjE2NDg3