Topographic survey

The benefits of laser scanning for mine survey are well-defined. The advantages of topography scanning before mining starts are less often realised.

Havilah Resources NL has discovered iron ore in the rugged northeast of South Australia. Drilling and exploration work
has identified what is under the ground, geologists have modelled the deposits, and the engineers can now plan how to mine.

‘An accurate pre-surface allows you to design your mine properly from the start,’ said Havilah Resources Chairman Bob Johnson. Once we have those surveys we can start making decisions - here’s the pit we’d design, this is where the stockpiles and infrastructure should be.’

The Maptek I-Site™ 8810 offers 5 different scan resolutions depending on the point density required. Terrain in the area is flat so standard resolution gives more than adequate survey coverage for the majority of scan locations.

The I-Site 8810 can be mounted on a vehicle and remain there for the entire day’s scanning, withstanding temperatures in the 40s, dusty conditions and vibration. Battery life is not an issue as the scanner runs off the vehicle power supply.

The I-Site mobile scanning system means the surveyor rarely has to leave the vehicle.

The lack of elevated vantage points makes it necessary to stop and scan every 450 metres or so. If foliage is too dense to get a backsight, the internal compass helps with scan registration.

Scanning beyond the orebody boundary ensures the surrounding topography is surveyed in enough detail for planning waste dumps, tailings dams and other mine infrastructure.

The I-Site 8810 incorporates internal GPS, wireless connection to the rugged scanner controller tablet, and vehicle compass calibration. It operates over a wide scanning temperature range.

The combination of vehicle mount and fast operating speed of the I-Site 8810 makes for very efficient field work, with time savings of about 3 hours per day over laser scanning from tripod setup.

At Havilah’s Grants lease, scanning was completed in about 4 hours, with data captured over 6 million square metres. Surveying the Maldorky lease, with fences and creek washouts, took 16 hours over 16 million square metres.

‘Getting accurate survey data at the start of the design process can really save time later on. With an accurate surface, the volume of the orebody can be calculated. Knowing how much material has to be removed in overburden, and where to store it, is the key to good mine design,’ concluded Johnson.

Thanks to Havilah Resources NL