Located 35 km northeast of Manado in North Sulawesi, Indonesia, the Toka Tindung Gold Mine, owned by PT Archi Indonesia, is one of Southeast Asia’s largest open-pit gold mining operations. The mine, produces an average of 130,000 ounces of gold annually. The Toka Tindung mine deposit features low-sulphidation epithermal gold mineralisation hosted within narrow quartz vein structures.

The situation

The complex geometry and scale of the narrow veins at Toka Tindung made blasting ore and waste separately impracticable. Blasting ore and waste together inevitably resulted in ore loss and dilution that adversely affected the grade and volume of ore delivered to the processing plant.

Historically, ore control at Toka Tindung involved manually defining mining polygons from pre-blast grade control models, then adjusting them in the field using visual inspections of blast indicators. Reconciliation results showed discrepancies between predicted grades and mill outputs, indicating that this method did not reliably account for ore movement caused by blasting. It also introduced safety risks, as personnel had to access the post-blast muck pile to locate and recover the blast indicators.

PT Archi Indonesia sought a practical and safe way to improve ore recovery and reduce dilution without slowing production. Improving post-blast material classification was a key step toward maximising recovery while maintaining head grade and productivity. 

"OREPro 3D Predict is an impressive solution that I personally would recommend to geologists who work in open pit mines. It can be implemented to develop a plan for addressing blast movement if it is identified as an issue in the mine-to-mill reconciliation process."

Wendhi Septiadi, Mine Geology Manager, PT Archi Indonesia, Tbk

Technical solutions

In 2025, PT Archi Indonesia partnered with Orica Digital Solutions to introduce advanced blasting technologies: SHOTPlus™ Premier and OREPro™ Predict. SHOTPlus™ Premier enables engineers to design, visualise, and analyse complex blast sequences with precision. Complimenting this, OREPro™ Predict simulates the dynamic 3D movement of blasted material, transforming the in-situ grade control model into a post-blast grade model, enabling more accurate ore classification and recovery.

The primary objective of the collaboration between PT Archi Indonesia and Orica Digital Solutions was to demonstrate how the integration of SHOTPlus™ Premier and OREPro™ Predict could significantly improve ore recovery and grade control. By incorporating blast movement predictions into the blast design process, the team aimed to optimise designs for recovery and dilution prior to firing the blast.

In the blast design workflow, multiple blast designs developed in SHOTPlus™ Premier were seamlessly imported into OREPro™ Predict to simulate blast movement for each scenario. This enabled a detailed assessment of the impact on ore recovery and overall blast performance from each design scenario.

By accurately modelling blast-induced material movement, generating post-blast models, and creating optimised dig polygons, OREPro™ Predict enables maximum ore value recovery while accounting for minimum mining unit, digging direction, and other key operational constraints.

To evaluate the impact, a comparative analysis was conducted focusing on ore recovery and overall net value. Table 1 compares calculated value of real blasting scenario optimised using OREPro™ 3D Predict against the original manual method of ore block delineation which does not consider blast movement.  The result shows a 28% increase in the value of the blast after it is optimised using OREPro™ 3D Predict. 

The workflow is significantly enhanced by seamlessly transferring the optimised dig polygons to the Fleet Management System. This eliminates delays and hazards created when mine personnel have to mark out dig boundaries on broken ground. 

The result

In the studied blast, integrating SHOTPlus™ Premier and OREPro™ Predict delivered a direct financial benefit exceeding USD $260,000. This improvement was driven by the ability to evaluate multiple blast scenarios and select the design based on net value calculated from simulated blast movement and optimised dig polygons.

This successful collaboration between PT Archi Indonesia and Orica Digital Solutions highlights the power of digital transformation and innovation in mining, delivering measurable improvements in ore value recovery while significantly enhancing safety for mine personnel. 

Acknowledgements

Orica Digital Solutions wishes to thank Archi Indonesia, Toka Tindung Operations for their support and permission to publish this case study.

Orica are grateful for the collaboration with PT Archi Indonesia, giving us the opportunity to jointly find improvements for your operation through our technologies, while complying with safety standards, maintaining positive interaction with communities and preserving the environment.

Authors: Ryan Pratama, Diyafakhri Andriandita, Chandra Budiman and Wendhi Septiadi
Date: June 2026