CORE SAMPLING

Gathering accurate borehole survey information

SPT employs unique technology in its equipment to ensure the most accurate borehole logging results

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The main objective of mining companies investment in exploration is to obtain core samples and from those samples obtain all the geological and hydrogeological information needed to make an evaluation of the reserve.

These core samples must be clearly positioned geospatially (X, Y, Z) otherwise they will not have the necessary validity to support any discovery since they determine the depth and size of the ore body.

Most of the geological programmes undertaken by mining companies are focused on the core orientation, however, that is only 50 per cent of the task.

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Stockholm Precision Tools' GyroMaster measures each data point at each centimetre of depth of a borehole

Stockholm Precision Tools AB (SPT), in Sweden, assists its worldwide clients' geological departments with training courses to teach that the other 50 per cent of the challenge is related to gathering accurate borehole survey information. The training emphasises that the use of correct technology such as SPT's GyroMaster and Gyro RigAligner is extremely important.

The best technology is not the one that has the best marketing but the one that complies with standard quality control procedures not only in theory but also in real data comparisons. It is the task of the mining companies to verify each technology and compare it with real borehole data making in-run and out-run comparisons, verifying that the north-seeking gyro matches the land surveyor. But this is usually not a reliable indication of the accurate result. SPT tools, thanks to Navibore Technology, make use of a down-hole autopilot, which is capable of finding and correcting itself along a survey path, eliminating all possibility of drift.

GyroMaster

The GyroMaster has been accepted as an industry standard and this reputation has been gained due to the excellent results that customers are getting from using it. It is the only north-seeking gyro capable of working in continuous mode from vertical to horizontal.

The big advantage offered by GyroMaster is that each data point is measured at each centimetre providing multiple X, Y and Z values which make the ellipse of uncertainty very tight. The accuracy is less than 0.1 per cent of the total measured depth compared to one per cent with other technologies.

Taking into account the importance of the clarification above, the GyroMaster and the Gyro RigAligner deliver the accuracy and precision needed by SPT's clients exploring and developing gold or other precious mineral reserves in the global mining industry.

Stockholm Precision Tools AB approach is totally different to what its competitors are promoting because its highly focused, in-country support service includes providing the customer with a calibration service that ensures the integrity and reliability of the tool provided in each country.

In addition, the company's remote control and onsite monitoring service of tool parameters from anywhere in the world ensures SPT can address any issues instantly saving time and money by avoiding having to ship tools out of the country or having people travel to the worksite for repairs. This remote backup service is especially important in difficult times when transportation can be a limitation for many mining companies.

Reliable technology

The accurate orientation of drilling rig is a key factor for the borehole deviation. For the development of mining drilling campaigns, specialised drilling companies are hired. They have their own protocols and procedures for conducting drilling activities but when it comes to the borehole survey it is difficult to control the parameters if reliable survey technology is not available.

This is an area where SPT has dedicated resources and developed a borehole survey gyro technology that has automated internal QA/QC (quality assurance/quality control) procedures ensuring that every borehole meets or exceeds the QC requirements.

Each survey is evaluated automatically by SPT's in-house designed intelligent software application which includes an integrated error model capable of preventing any problems with erroneous data and thus securing the customer's investment. In addition, its portable automatic calibration stand is always available in each county.

As part of the drilling programme, the mining company provides an action plan that includes the starting coordinates of each drilling point. The drilling company must then assign its machine to ensure that it is starting at the exact place that has been assigned according to the plan (Inclination or dip angle, azimuth, and coordinates). This control is as equally important as the well trajectory measurement.

Reduce integration risk

If the drilling rig does not start with the initial data provided by the mining company, there is a risk of economic loss (loss due to drilling at a wrong point, or additional cost for repeating or reinstalling the machine with the actual data).

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The driller operated Gyro RigAligner uses north-seeking technology paired with automated software to replace the need for 3rd party surveying services

If the drilling rig starts correctly with accurate information and in the final measurement there is still a difference in angle and/or azimuth, it is an operational or terrain problem.

The approach of SPT is to ensure the SPT Gyro RigAligner works back-to-back to with the GyroMaster providing the client with both technologies calibrated and verified by the same manufacturer thus reducing the risk of any integration problems.

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