CREATING GRADE CONTROL BLOCK MODEL USING VULCAN GRADE CONTROL

The Cortez Hills and Pediment gold deposits are on the south side of Crescent Valley associated with the Cortez window. The Cortez Hills sub-vertical mineralized breccia and thrust fault-related Middle and Lower Zones are hosted by Horse Canyon, Wenban, and Roberts Mountains units. The Pediment deposit is contained within Miocene-age conglomeratic sediments located immediately southwest of the Cortez Hills deposit.

A grade control model has been constructed utilizing the generated block model output files created during the grade control process. The generated block model files created by each blast are appended into one large model through a set of procedures and manipulations. The result is a model that represents what has been mined and how the material was routed. It is unique in the fact that it fully utilizes the Vulcan Grade Control Module and its features.

The search dimensions and orientations for Cortez Hills and Pediment were optimized with unique parameters for each deposit. Based on the resource model parameters, it allows for an accurate and reliable generated block model to be estimated. The block definition file for the generated block model was also modified to add the necessary variables for manipulation.

The grade control model creates a much more accurate method for reconciliation to the reserve model for end of month reporting and model performance. Individual blocks grades are able to be averaged within a mining shape by material type, as opposed to one average grade per block out. This allows the preservation of the variation of grades within an individual block out.

The procedures of this model were developed while working at a previous mine that used the same Vulcan Grade Control Module. It was instrumental in leading to a more accurate reconciliation and end of month reports, in addition to saving significant amount of time. The model was implemented there in 2012 and is still being used successfully today.