Samancor Dikwena tailings dam collapse: Early warnings allegedly ignored

The incident affected access to nearby mine shafts, swept away vehicles and damaged Eskom power lines. It also placed renewed attention on the risks associated with mine residue deposits and the systems used to detect possible failures before they become emergencies.

Investigation identifies failure at northern perimeter wall

Mantashe said the department’s post-incident investigation traced the failure to one section of the facility: the northern perimeter wall of Compartment 1B.

The investigation identified persistent seepage and prolonged saturation associated with that wall. In simple terms, seepage involves water moving through or from a structure, while prolonged saturation can affect the stability of earth and engineered embankments. The significance of those findings is that the department linked the collapse to conditions that had developed over time rather than describing it as an unexplained, instantaneous event.

The probe also found shortcomings in the mine’s safety systems, including inadequate monitoring and early-warning measures for a potential tailings dam wall failure.

Early-warning systems are intended to provide information about changing conditions so that mine operators can investigate risks, protect workers and take preventative action. Where monitoring is inadequate, changes affecting the integrity of a facility may not be identified or acted on quickly enough.

Urgent engineering work was recommended

According to the minister’s reply, a structural-integrity report had already called for urgent engineering work at the facility. One of the recommendations was the installation of a continuous drainage system.

That work was not carried out, the minister said. The failure to implement the recommendation is central to concerns that warnings about the facility’s condition were not adequately addressed before the collapse.

The available findings do not establish every decision made at the mine or identify who was responsible for the outstanding work. However, they do show that a report had recommended urgent intervention and that the recommended engineering measure was not implemented before the incident.

Depositing tailings halted after the collapse

The department considered the situation serious enough to order an immediate halt to the deposition of tailings into the relevant storage facilities. Workers at the dams were also required to move to safety.

Tailings are the residue left after minerals have been processed. They are generally stored in specially designed facilities, where the stability of walls, drainage arrangements and water management are important parts of safe operation.

Stopping further deposition limits the amount of additional material entering a facility while its condition is assessed. It also gives investigators and engineers an opportunity to examine the structure and determine what measures are needed before operations can resume.

Mine ordered to conduct investigations and prepare a turnaround plan

Samancor was required to conduct its own investigation under Section 11(5) of the Mine Health and Safety Act. The mine was also instructed to prepare a rehabilitation plan and submit a turnaround strategy setting out how mining could be conducted safely.

In addition, the department required the employer to appoint an independent suitably qualified person or team to carry out a comprehensive forensic investigation and environmental assessment.

The involvement of independent specialists is intended to provide a detailed examination of the technical, environmental and operational factors surrounding the collapse. Such an assessment can help distinguish between immediate conditions at the failed section and wider issues affecting other parts of a tailings storage facility.

Operations cannot restart without approval

Mantashe said tailings deposition could not resume until the required measures had been implemented and an acceptable presentation had been made to the Principal Inspector of Mines.

This means the mine cannot simply return to its previous operating arrangements once the immediate incident has passed. Any resumption must follow the department’s requirements and be supported by evidence that the necessary safety measures have been completed.

The restriction also places responsibility on the operator to demonstrate that the facility is safe enough for the next stage of operations. The department’s approval process provides an additional regulatory check before deposition can begin again.

Department reviewing risks at other facilities

The minister said the department had urged mine employers to assess risks linked to mine residue deposits before the Dikwena collapse. It had also issued a guideline for a mandatory code of practice on the issue.

Inspectors of Mines would continue checking compliance through routine inspections and audits, Mantashe said. The department will use the findings from the Dikwena investigation to determine whether further regulatory measures are needed.

The assessment of the remaining compartments at the facility was still under way. That work is important because an incident affecting one section does not, by itself, establish the condition of every other compartment. Each area must be assessed on its own condition and the risks associated with continued storage.

Why the findings matter

The collapse highlights the importance of acting on engineering recommendations before a safety concern develops into a failure. It also shows why monitoring, drainage and early-warning systems are critical components of tailings facility management.

For workers and communities near mining operations, the issue is not limited to the structural condition of a single wall. A tailings facility can affect access routes, vehicles, power infrastructure and the continuation of mining activity when a failure occurs.

The department’s investigation has identified several areas requiring attention: persistent seepage, prolonged saturation, inadequate monitoring, insufficient early-warning measures and an urgent drainage recommendation that was not implemented.

The next steps will depend on the completion of the required investigations, environmental assessment, rehabilitation planning and safety measures. Until the Principal Inspector of Mines accepts the mine’s presentation, deposition at the tailings storage facilities is not permitted to resume.