FEATURE
be high too and the subsequent effect on the mining company ’ s investments could be negatively affected .
The following table ( Fig . 3 ) gathers the data and technical specifications of different tools , taken from the websites of their respective manufacturers . Here the error in the final coordinates is evident . Drill trajectory measurement with the use of the GyroMaster ™ true north seeking reduces this error to a minimum ; showing , with real data , that Stockholm Precision Tools is the leader in quality control of trajectory measurement .
Quality Control in Mineral Exploration In addition to the risks that we have already mentioned with the use of a lowprecision north-seeking gyroscope or a reference gyroscope , there is another concerning factor . This is that those who decide to use these tools in their projects do not always have the mechanism or technology to verify that the value of 0.3 º of precision in the inclination , coincides with the reality of the measurement . Many times , it tends to be higher , not to mention the obscure azimuth or direction accuracies stated .
When it comes to quality control and quality assurance in using gyro technology for mining exploration projects , Stockholm Precision Tools ( SPT AB ) has implemented a rigorous model , ( see Fig . 4 ) of controlled checks and audits , making it one of the few companies who have developed and implemented a Quality Assurance and Quality Control ( QA / QC ) process . This process can be seen in both borehole trajectory measurement and measurement during core recovery in B , N , H , P holes .
Understanding the risk for investors of often having millions of dollars invested in mining projects and the devastating effect that this environment of errors caused by the lack of information can have , we are continually ensuring the quality control of our tools and process . Proof of this is also our Gyro RigAligner™ , a compact and lightweight tool that looks for True North , and aligns the rig platform in less than 5 minutes . It is also the only 3-axis aligner that works in all directions ( vertical , horizontal , and inclined ).
Fig . 4 . Quality Control Process implemented by Stockholm Precision Tools ( SPT AB )
Ways to Check the Accuracy of a North Seeking Gyro Survey Tool There are several methods to check the accuracy of a true north gyroscope or north-seeking gyro , the most effective being the measurement in a deep well ( about 1000 meters approximately ) and the subsequent comparison between the values of the In-Run & Out-Run . In addition , the initial data is verified by the topography department .
Another way to check the precision of a tool is to have a calibration stand , such as the Universal Calibration Stand CF . 02 ( Fig . 5 ), designed to work with SPT tools .
In other cases , the manufacturer should be required to show the ability to measure vertically , i . e . -89 degrees in continuous mode , and to demonstrate that both down and up values must not exceed 0.15 % in the coordinate NS / EW .
Let ’ s explain this in more detail : before selecting the gyroscope to be implemented in a project , In-Run & Out-Run measurements must be made to verify that the azimuth and inclination data are repeated according to the specifications declared by the manufacturer .
Both measurements must be evaluated , and the data must be the same . It is the best way to check the quality of the tool , moreover , these measurements should be made in different inclinations and directions .
Finally , the tool should be tested under harsh environmental conditions . If that opportunity does not exist , it can appeal to the topography department to use the calibration stand to calibrate the gyro tool .
The main problem we have detected in our analysis is the lack of a reliable quality control standard for well trajectory measuring technologies globally and that the client is often guided by published specifications , by the ease of use , low prices , or by other factors unrelated to the precision of the tool . Consequently , this can lead to erroneous decision making and financial losses for investors , which could have been easily avoided .
Fig . 5 . SPT Calibration Stand
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