How to Apply Handheld Laser Rangefinders in Underground Mines?
As a type of rangefinder, the handheld laser rangefinder possesses unique functions and characteristics compared with ordinary rangefinders.
The application of DISTO in mining mainly relies on combining the DISTO with a domestic theodolite to form a prismless semi-total station. It is used for measuring survey points, section heights, stope volumes and other parameters in underground workings.
Before the company purchased the DISTO handheld rangefinder, what was their original underground surveying method? According to a person in charge of the survey unit, they used a combination of theodolites, tape measures, fishing poles and domestic pulsed rangefinders to conduct underground stope surveys. The main drawbacks of this method are listed below: ① Low measurement accuracy. A set of data can illustrate this point: at the end of 1998, two geological survey teams jointly measured the volume of one stope. One team obtained a result of 55,000 cubic meters while the other got 68,000 cubic meters. Each measurement yielded a different value, and the discrepancy between repeated readings was so large that they dared not continue the survey. ② Slow speed and low efficiency. Underground working conditions are far inferior to those on the surface. Restricted by harsh underground environments, poor lighting and low safety margins, survey work proceeds slowly with low productivity. It often takes several times longer than normal to complete a single survey point. ③ Although domestic pulsed handheld rangefinders can perform distance measurement, they adopt ultrasonic ranging technology. Operators cannot visually locate the target point. Coupled with their short measuring range and low precision, their scope of application is greatly limited.
Changes after adopting the DISTO: For underground surveys, surveyors only need to set up one theodolite together with the rangefinder. No personnel need to stand at the target point. Comprehensive and relatively accurate measurement tasks can be completed smoothly in a short time. It overcomes the previous disadvantages of low speed, poor efficiency and insufficient precision. In particular, the visible red laser dot of the handheld laser rangefinder is highly praised by surveyors for underground measurement. The handheld laser rangefinder can also be used independently underground, which is quite convenient. It can store a large amount of measurement data, eliminating the need for manual on-site survey records. Besides convenient underground operation, handheld laser rangefinders can also be applied to open-pit slope measurement and setting-out.
