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The mine surveying profession in Zimbabwe is rapidly evolving from traditional measurement work to a strategic role at the heart of mine management. Stewart Gumbi, President of the Association of Mine Surveyors of Zimbabwe (AMSZ), explains how technology, regulation, and collaboration are transforming the profession from “Survey to Strategy.”
Here is how our interview went.
Thank you for discussing the changing role of mine surveyors. It’s a significant time for our field, especially in Zimbabwe.
The Association of Mine Surveyors of Zimbabwe, AMSZ, is leading a shift from traditional surveying to strategic leadership, as highlighted by our recent conferences, “From Survey to Strategy” in 2024 and “Advancing Data Integrity, Operational Excellence, and Investor Confidence for a Thriving Zimbabwean Mining Sector” in 2025. Surveyors now act as spatial data custodians, independent production auditors, and vital links between digital plans and physical operations. With new technology and updated regulations from the Ministry of Mines and Mining Development MMMD, the mine surveyors continue to play a key role in ensuring safe, compliant, and profitable mining. I look forward to sharing insights on our profession.
What is the role of mine surveying in designing and validating mines, pit limits, and stope layouts?
Mine surveyors bridge the gap between engineering plans and on-site reality through a continual process of preparation and validation.
1. Preparation (Informing the Plan)
Surveyors provide precise 3D topographic and as-built models essential for creating accurate mine designs. A solid initial survey ensures mine plans are both practical and economical.
2. Validation (Controlling the Plan)
Surveyors act as independent auditors by:
- Setting out design limits in the field,
- Surveying completed excavations with advanced tools, and
- Comparing designs to as-built conditions to identify deviations.
Reports highlight overbreaks, underbreaks, geometric compliance, and safety concerns. Accurate stope scans inform engineers, helping optimise future stope designs and improve resource recovery and safety. Surveyors don’t just measure compliance—they enforce it, tying every variance directly to financial outcomes.
How do you collaborate with geologists and mine planners to ensure that survey data supports optimal extraction and safety?
Practical and Effective mining relies on close teamwork between surveyors, geologists, and mine planners. Each role depends on sharing accurate information: geologists create resource models, planners design based on survey maps, and surveyors set out plans and verify results. Regular feedback ensures designs match field conditions and helps update geological models.
The Integrated Workflow
Geologists build the 3D resource model; planners use this and surveyor maps to design safe, cost-effective mines; surveyors set out and record actual excavation results.
The Critical Feedback Loop
Surveyors report on how well the as-built matches the plan, guiding planners on practical adjustments and cost efficiency. Surveyors also provide precise coordinates for geologists, helping refine resource models after excavation.
The Technological Enablers
Collaboration is supported by integrated software and Mining Data Management systems, ensuring everyone works from up-to-date plans and data. Professional workshops and shared data standards further strengthen this technical partnership, making spatial control the backbone of all mine planning.
How do you ensure accurate reconciliation between mined material, processed ore, and resource models?
Reconciliation compares the geologist’s resource model (prediction), the mine’s reported output (production), and what the plant actually processes (final product). Surveyors play a vital role by providing precise “actual” measurements to pinpoint where and why discrepancies occur, enabling better reserve understanding.
Surveyor’s Role in Reconciliation
The reconciliation considers three key components:
- Resource Model: Predicted tonnes/grade before mining.
- Mined Material: Surveyor’s as-built survey, serving as the first actual measurement.
- Processed Ore: Certified plant production figures, the ultimate reference point.
Ensuring Accuracy
Surveyors are accountable for “Mined Material” and “Stockpile” figures, making accuracy crucial. We achieve this by:
- Conducting precise 3D as-built surveys (often using LiDAR/SLAM)
- Accounting for blast movement to avoid misaligned dig lines
- Performing meticulous stockpile surveys to prevent phantom variance
- Collaborating across teams and ensuring data consistency (e.g., adjusting for moisture content differences)
This process not only identifies discrepancies but also improves planning. Reliable data converts unknown variances into predictable factors, reducing financial risk and supporting continuous improvement.
What specific techniques and controls maintain accuracy during underground surveying in GPS-denied environments?
In underground settings with no GNSS access, surveyors rely on a dead-reckoning approach, primarily using a high-precision traverse. Traverses consist of wall stations measured with a 1-second total station, with each station’s position calculated from the previous one. Errors can accumulate over distance, so strict procedures are needed:
- Observation Protocols: Measure angles on both faces, distances both ways, and use forced-centring to reduce errors.
- Gyro-Theodolite: Finds True North for absolute azimuth; sets initial direction and re-checks traverse periodically to control angular errors.
- Closed Loops: Connect traverses back to starting points or known coordinates to calculate and adjust misclosure.
- Redundant Resections: Use measurements to three or more control stations for setup quality and local stability checks.
SLAM Technology and Hybrid Methods:
SLAM offers fast mapping for complex areas, but it drifts and isn’t suitable as primary control. The best method uses a precise traverse and gyro for establishing main control, while SLAM scanners handle secondary mapping tied to known traverse stations.
Survey control is critical; mine operations depend on the accuracy provided by surveyors, underlining the importance of professional standards.
How do you manage and correct cumulative errors when extending underground survey networks?
Cumulative error is a major challenge in underground surveying. Each measurement introduces small random errors that build up over a traverse. Rather than eliminating error, surveyors aim to quantify, control, and correct it through four main stages:
- Management: Minimise errors by using calibrated instruments, strict field procedures, and techniques like zig-zag traverses.
- Azimuth Correction: Use gyro-theodolites to reset directional error with true north bearings.
- Position Correction: Employ closed loops by returning traverses to known points, allowing calculation and correction of misclosure.
- Adjustment: Apply statistical methods (typically least-squares adjustments) to distribute and correct error across the network.
The “Open Traverse” Problem
In situations where a closed loop isn’t feasible (e.g., new mine declines), error management and regular checks are crucial. Two-way traverses and repeated station surveys help detect issues. Surveyors must balance rigorous control for critical measurements with faster methods for production tasks, weighing operational needs against risk to maintain survey integrity.
How will automation, AI, and real-time data shape mine surveying?
These technologies are converging to enable fully self-optimising mines, with surveyors as key information architects.
1. Automation and Robotics
Autonomous vehicles and robotic surveyors already operate in mines. Surveyors will move from field data collection to managing automated fleets—overseeing drones and robots that handle routine tasks remotely, greatly improving safety by removing people from hazardous zones.
2. Artificial Intelligence (AI) and Machine Learning (ML)
AI rapidly interprets collected data, automating point cloud analysis, feature extraction, and reconciliation. Surveyors will approve AI-generated compliance reports instead of manual processing. Advanced analytics will allow for real-time pattern recognition—predicting slope failures and identifying resource-rich areas using integrated geological and survey data.
3. Real-Time Data and the Digital Twin
Automation and AI combine to create a dynamic “Digital Twin”—a live 3D replica of the mine updated by autonomous systems. This allows managers to test scenarios virtually and enables automatic rerouting of equipment according to real-time conditions.
The Surveyor’s Role
Far from replacing surveyors, this shift elevates their responsibilities: ensuring data accuracy, maintaining the digital twin, and focusing on advanced analytical work. Surveyors remain essential as trusted custodians of mine data, guaranteeing the integrity of digital models and supporting strategic decision-making. I encourage all Mine Surveyors to adopt this technology quickly, learn it thoroughly, and apply it in their daily work to provide better services for our expanding mining industry.
Conclusion
The mine surveying profession in Zimbabwe is transitioning from manual methods to a digital, strategic role. With new government regulations and technologies like LiDAR, UAVs, and AI, surveyors are now key leaders in information management and data governance in mining. The Association of Mine Surveyors of Zimbabwe (AMSZ) is dedicated to equipping its members with the necessary skills and recognition to advance a safer, more sustainable, and profitable mining sector.
