Thread: Compass Brands

Originally Posted by Tussock

Have seen 40 million dollars worth of drilling pointing in the wrong direction because 20 people got confused over that rule. Not as simple as first glance.

Who sets out a $40m drilling operation with a compass anyway?

I'm an old school kinda guy Dan My take is that you need to understand the fundamentals, and be able to apply them, irrespective of the type of compass, or wether declination is stated as positive or negative. Like Tussock said, it is not that hard to get it wrong, or to get confused, so helps to practise, practise, practise. I've consciously stopped carrying a GPS cos I found it made me lazy wrt map & compass skills.

MSC is still teaching add/subtract...

Can you explain what you mean by bearing off method ?

Originally Posted by Tussock

What were you going to use as an alternative?

I'm a surveyor so can think of plenty of options - total station, GPS/GNSS being the most common methods.

I'm suprised the work (for mining?) is low enough precision that a compass gives acceptable accuracy, they're certainly never considered an option for survey work. Sure there was the odd survey done with by chain and compass back in the 1800s, but we still get some headaches resolving the errors they left.

If your accuracy requirements can be met by a compass then it is definitely the simplest, most portable and reliable piece of gear though - I'm just surprised thats all thats needed.

Shit aye. Better get rid of my chinese hunk a junk.! $1000us compass hope that thing points towards deer!

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Originally Posted by Tussock

Points towards gold.

Sweeeeeet. Should pay itself off pretty quick then aye.

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Originally Posted by Tussock

drilling/surveying stuff

Ah gotcha, yep makes sense for that use. The only drilling control work I've done was surface location for vertical bores - they were trying to locate historic mine tunnels under a site to avoid putting buildings on top of them. Keeping within half metre with a compass is doing well, you must be doing something right!

A lot of second hand gear hit the market when firms went bust or downsized during the last recession which pushed prices down, there are also a few Chinese manufacturers selling survey gear around half the price of the major players now - most of it uses copies of previous-gen Trimble chipsets so should be pretty reliable too.

from me old TF days
My Grannie Sucks=magnetic -grid-subtract magnetic variation
Grand Mas Arse=grid-magnetic -add magnetic variation.

mind you all compass work was in mils ,so dont know if this is still used.

Tussock talking of F..ups with the math reminds me of teaching a TF artillery crew map resections. I asked one gung ho gunner where he'd placed his 105mm howitzer
Hmmmm-plotted on the map it was smack in the middle of lyttleton harbours main shipping lane.
geez that cost him a few ales at the end of the day!!