Better slopes with better deviation detection

Better slopes with better deviation detection

Overview

Since 2015 Antucoya mine has been controlling the construction of the pit walls using two metrics in order to improve the stability, safety, and economic value of the mine, namely: (1) the Design Factor, which evaluate the as-built compliance of the pit walls to the design plan; and (2) the Condition Factor, which assesses the health, damage, and scaling of the bench faces.

Monitoring and controling using these metrics resulted in new best practices defined by the Geotechnical, Drilling and Blasting, and the Loading and Hauling teams. The result is improved compliance with the Berm Width of the benches, which in turn has improved the safety and operational continuity of the mine.

Solution

To improve slope construction, the Geotechnical team at Antucoya mine follows a series of steps which uses SICT to automate the Design Factor calculations. The steps were:

1. Use of the Design Factor to evaluate design parameters such as: Berm Width, Bench Face Angle, Toe Line, etc.
2. Evaluation of the Condition Factor through the mapping of elements such as the presence of half barrels, crest fracturing, face profile or the presence of unstable blocks, among others.
3. Identification and location of compliance deviations with the design and quality of the bench faces.
4. Root cause analysis of the elements that create good or poor slope construction compliance results, based on the correlation with the geotechnical-structural model and the drilling and blasting practices.
5. Review the results of the analysis together with the Drilling and Blasting team, confirm the root causes of the deviations, and collaboratively define the modifications to the process to achieve better slopes.

Using this methodology, the Geotechnical and the Drilling and Blasting teams have a standardized way to see the results of the constructed slopes, allowing them to improve the design of the final wall blasting, introducing the following modifications:

1. The production holes were moved away from the future crest of the bench,
2. A negative sub-drilling was established in the buffer holes (bottom of the hole above the future floor level), and
3. the load configuration of the buffer row was changed.

Impact

Implementing these changes to the drilling and blasting processes have produced the following benefits:

1. Increase in the retention capacity of the built benches, given by an increase of 13% in the Berm Width; improving from an average of 6.27m to 7.11m in the 4th quarter of 2019.
2. Better communication and collaboration between the superintendents involved in the pit construction, and improved compliance with the wall design parameters.
3. Improved scaling and toe lines resulting from training and objective feedback to shovel operators.

These improvements are made possible by SICT.

“The implementation of SICT has allowed us to detect deviations in the construction of benches in a timely manner and to visualize them in a simple and georeferenced way, which has facilitated communication with the different areas, positively impacting the achievement of the berms of the benches built in Antucoya.”

 Boris Duarte, Senior Geotechnician, Minera Antucoya.