of previous AMA Tunnel Lasers, but with significant improvements to make tunnelling easier. The T8 design has been perfected during more than 20 years of service. It is extremely robust, built to cope with the harsh tunnelling environment.


The alignment mechanism in each axis consists of two counter working precision thread alignment screws, that lock the laser position in place for maximum stability of the alignment. The 5/8” thread in the bottom allows for use of replaceable, precision instrument positioners. This gives the possibility of dismounting the instrument during blasts when working close to the work face.


The visibility of the T8 laser spot is excellent, making the T8 good for ranges up to 800m. The laser power output is 3,5mW (5mW as option). The laser beam is focused at 600m, which ensures that the laser spot diameter at 600m is typically 35mm.
The T8 is powered by a laser diode. The dura-bility is superior to previous HeNe technology, and the cost of replacing a damaged laser diode is lower.


The T8 is engineered for durability. Its thick-walled aluminium housing can take abuse. The optics are protected against blast rock damage by a thick optical glass, that is easy to replace in case of damage. The alignment mechanism is over-dimensioned to give further protection against damage. The T8 is fully water and dust proof, and is purged with nitrogen to avoid condensation on the optics.


The T8 comes in two power versions, 12VDC and 110-230VAC. The 12VDC version draws less than 50mA, compared to 1A for the previous T810. This means that a car battery will power the T8 for over 1000 hours. It handles 12 to 30VDC, and is fully protected against accidental polarity switch. Fused with a self resetting thermal fuse. The AC version handles 85 to 264VAC, 47 to 63Hz. Fused with 1,6A slow fuse. Mains filter handles dirty power conditions with high transients.