Ore Control Technological Innovations at Goldcorp Peñasquito Mine

Author: Christian H. Calderón Arteaga

Located in the northeast corner of Zacatecas State, Mexico, Peñasquito is Mexico's largest gold producer, consisting of two open pits - Peñasco and Chile Colorado - containing gold, silver, lead and zinc. Mining (pre-stripping) began in 2010 and full production in 2011.  The open pit mines feed both a sulphide concentrator (mill) and a heap leach pad. Peñasquito’s project is owned by Goldcorp, Inc. and is a poly metallic deposit with gold, silver, zinc and lead being recovered as payable metals.

New ore control technology

Due to expected lower grade ores with advancing mine-life, Peñasquito is facing a declining metal production profile. The requirement of the ore control system to accurately predict ore feed characteristics is critical to maximising metal recovery at Peñasquito, while the ability to accurately route materials from the ore control system is critical to site success. These challenges have been overcome by the adoption and implementation of a new ore control (OC) technology from Hexagon’s Mining division.

The solution has improved geomodelling, material routing and model reconciliation. The technology’s implementation has also significantly improved selectivity, performance and data management while reducing the variance between planning and execution. This has helped to drive overall improvement across the operation.

This project requires managing blasthole data, model interpolation and model calculations, among other modelling related tasks.  Also required are the creation of new ore control databases to manage material routing, daily mining, model reconciliation and the communication with third party systems at the mine. The implemented solution uses the blasthole database as a primary input while also serving as material routing input for the fleet management system, and as a source to generate various reports. The OC system data is turned into information that supports the decisions and evaluation making processes at the mine.

From weak to wise workflows

The process used by Peñasquito’s ore control team to update the OC model was beset with issues: a lack of knowledge of the intermediate steps from the users, the excessive number of steps, and the ability to troubleshoot when there were errors in the process. These issues prevented Peñasquito from running a robust ore control model that could be accountable for the new needs of the mine. The team sought greater confidence and reliability in the model. 

This old process was replaced with a newer, standardised workflow that allows the users to trust in the results and to make informed decisions with higher confidence. Using HxGN MinePlan Operations (formerly MineSight Axis), a new workflow for Peñasquito’s OC was designed and implemented. The new workflow includes the usage of different tools to resolve the issues that ore controllers had faced using the previous process. 

“Thanks to the new technology, we have increased the reliability of the model, which leads to higher confidence in our reserves,” said Juan Barrios, ore controller for Peñasquito. “We have also reduced the working time to process a blast polygon, and now we can visualise and report the results almost in real time.”

Improving ore control processes

The implemented solution includes new tools to:

• Manage the OC model update process
• Manage the polygon routing and progress
• Report and release the necessary information to all mine consumers
• Run the model reconciliation, where the exploration model is compared against the OC model.

These tools were placed together in a custom design that allows them to work in a step-by-step process. Information flows between the tools so the users can report the necessary information to make informed decisions with more confidence.

Qualitative, quantitative and collateral improvements have been documented since implementation. 

Qualitative improvements include:

1. a) Data security has improved by implementing the usage of SQL server technology;
2. b) The process is now automated with automatic calculations, i.e: automatic naming of the OC cut, or the cut’s automatic material assignation based on reserves from the block model;
3. c) Process is auditable, meaning that the results are repeatable even after a long period of time;
4. d) The user can now interact with the data to make informed decisions.

Quantitative improvements include:

1. a) The new OC process is much faster with an average reduction of 75 per cent in the processing time;
2. b) Monthly reconciliation processing time was reduced by approximately 80 per cent.

Collateral improvements include:

1. a) Density calculations are now reconciled between exploration and OC models;
2. b) A new pit has commenced with no additional project setup required;
3. c) a new forecasting report of the available material for the planning department was implemented;
4. d) New daily and weekly reconciliation reports are possible now and implemented by the end users.

The implementation of the new ore control system from Hexagon’s MinePlan software narrows the gap between what is and what should be. The software helps to not only shape smart change, but also to unlock and realise significant improvements in the OC process.