A check survey is an independent re-measurement that confirms — or challenges — the accuracy of survey work, whether done in-house or by a contractor. Survey House performs this auditing function for new mines and as third-party checks on existing surface and underground workings, acting for either a client or a contractor.
The cost of getting it wrong is real: the company has seen a hoist chamber and main shaft set out in the wrong place, where rectification and contract extension were estimated at around R14 million per month over six months. Independent control surveys are essential to maintaining the accuracy of an underground network, whose bearing can drift over time if left unchecked.
The work includes re-observing and adjusting control networks, verifying setting-out and as-built positions against plan, checking primary bearings with gyro observation, and confirming statutory survey records and plans. On the Mine Audit & Consulting side, a surveyor on the shaft offsets for over- and under-break before each blast — assurance that protects management, regulators and partners alike.
An audit re-observes independently rather than reviewing the original surveyor’s computations. Reviewing arithmetic confirms only that the arithmetic was consistent; it does not detect an error in the observations it was based on.
Where control is suspect, it is re-established from an independent origin — national trigonometrical stations where available.
An audit reports the state of the work at the time of audit. It is not a warranty of work performed afterwards, and where access or programme limits the audit, those limits are recorded in the report rather than left implicit.
