Check Survey or Survey Audit: Define the Question First

Check survey and survey audit are often used as if they were the same request. On survey audits and check surveys, they answer different questions, and naming the wrong one gets the wrong scope quoted back.

Deciding whether the situation warrants an independent review at all is covered in our article on when to commission a survey audit. This article assumes you have decided, and need to name the right thing.

Check survey or audit: the two questions

A check of survey work can range from re-observing specific measurements on site to reviewing the reported process and records, and these different depths of check answer different questions.

A check survey goes back to site and measures again: a stockpile, a set of control points, a pick-up of built work. It produces an independent figure that can be set beside the disputed one. An audit looks at how the work was done: the control used, the methods, the computations, the checks and the records. It produces findings about the process, and it may show why a figure came out as it did.

Why the difference changes the quote

A provider prices what it is asked for. Ask for an audit when the real need is an independent volume, and you may receive a careful review of procedures and no new figure. Ask for a check survey when the real need is confidence in a provider's monthly work, and you may receive one re-measured figure that says nothing about next month.

Writing the request

A clear request names the question, the figure or process in doubt, and the evidence the provider will be given, so the scope that comes back answers the question asked.

For a check survey

State the figure in dispute, the date and extent it applies to, the control and coordinate system it was produced on, and the surfaces or points involved. On volumetric surveys and stockpile surveys, the date matters most, because material moves after the original survey and a later re-measurement may describe different ground. Where the original basis is not recorded, say so, because it limits what the comparison can show.

For a survey audit

State the work to be reviewed, the period it covers, and the records that will be made available: field notes, computations, control schedules and reports. Say what decision the findings will support, such as renewing an appointment, accepting a handover or resolving repeated disagreements. On long-running work, such as underground mining surveys, an audit may also include selected re-observation, which adds a site re-measurement to the review. Name that in the scope if you want it.

Independence

Whichever you choose, the value of the result depends on who does it. A review by the team that did the original work is a useful internal check, but it is not independent. Ask who will carry out the work and how they relate to the original provider.

It also helps to say what you will do with the result. If the answer will be shared with another party, such as a contractor, a client or an auditor of the mine's own reporting, tell the provider at the start. The report can then be written for that reader, with the basis of every figure stated, rather than rewritten later. And say how quickly you need it. A re-measurement on site depends on access and on the ground not changing in the meantime, so a delay can reduce what the result is able to show.

Where survey cannot help you

Choosing the right engagement makes the answer useful, but some questions sit outside what either engagement can settle.

A re-measurement cannot recover ground that has since changed, so it cannot always say what the original figure should have been on its date. An audit cannot test records that were never kept. Neither one can decide a commercial dispute. They provide evidence for the people who decide. Survey practice in South Africa is regulated through the South African Geomatics Council, which is a useful reference for the professional standards any review is measured against.