GEO-MRI | NMR Technology: ACTION above the clouds!

At 5 selected survey sites on the Yanacocha mine ground, NMR drill hole profiles were logged with Vista-Clara Inc. technology between 85 and 115m.

To ensure the smoothest possible measurement, the logging vehicle must be optimally aligned with the winch. The rigging of the equipment components is performed on a wooden pallet. The functionality of the entire equipment chain is tested outside the borehole before it is lowered into the borehole for the actual measurement.

It requires good coordination of the entire team to move the (sensor | bottom + digital | top) components from the initial horizontal-resting to the vertical position, bolt them together and securely hang them in the borehole before lowering it downhole. Driving the winch at a very low speed rate ensures recording a high-resolution logging profile.

Vista-Clara Inc. technology is being used at 5 selected monitoring sites on the Yanacocha Mine property for drill hole logging. Drill hole profiles are compared to previously determined stratigraphy measurements.

Because of the constant threat of an approaching thunderstorm (and therefore a potentially narrow window of logging opportunity), we measure from the surface to the respective maximum borehole depth - rather than logging from the deepest to the zero measurement point as we usually do.

We are lucky, because only at the last measuring point - almost as feared every day - shortly after the noon hour "Thunderstorm Red Alert" is declared mine-wide: all persons on the mine site have to stop their respective work outside immediately and seek shelter - in a vehicle or in specially arranged shelter containers. In our case, the measuring probe remains submerged in the borehole, and all measuring systems are switched off to avoid electrical damage.

Thunderstorms are a potential dangerous hazard at this high altitude and can occur within a very short time. A sophisticated warning system on the mine site reacts to atmospheric disturbances and uses a siren alarm to prompt all persons being outside a building | vehicle to immediately seek suitable shelter.

After a few hours, the atmospheric disturbance is usually over, and we can complete our measurement. In reversed order, the entire measurement chain is pulled out of the borehole, successively disassembled, stowed away, and prepared for the next measurement mission.