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Sven "... If anyone had done this before me": In the early(ish) days of palaeomag people used drills with rigs - cumbersome things, first drill your bolt holes to lock the rig to etc. Then they realised that they could get away without them. So yes, there is a history - there are references in Collinson, DW, Creer, KM & Runcorn, SK (eds) 1967 Methods in Palaeomagnetism (Elsevier) - McElhinny talks of drilling 2 ft (60 cm). But I don't think it's much help to you! Cheers Bill ________________________________ From: Tectonics & structural geology discussion list on behalf of Sven Morgan Sent: Wed 19/04/2006 18:51 To: [log in to unmask] Subject: Re: deep rock core drill thanks Zoe, I have collected cores down to 15 cm using the standard paleomag drills (converted petrol powered chain saws), but I want to get deeper. I have seen a lot of deeper-going equipment from mining equipment websites, but I wanted to know if anyone had done this before me. Several folks suggested going with a mining/drilling contractor - which I might do. thanks again, Sven [log in to unmask] wrote: Hi Sven I've used a petrol-powered palaeomag drill to collect samples from sandstones. The longest core we ever managed to get was about 10 cm from a more massive sandstone. A major problem in well-bedded sandstones is that they tend to shear into little biscuit shaped pieces along the bedding. To get cores longer than that the trick is holding the drill still enough so you don't shear the core off at the base. The taller and heftier members of the field team had more success (i.e. not me!). For over 50 cm you might have to design some kind of rig to hold the drill still? And you'd need longer coring bits than the standard... The drill was petrol-powered and light enough for me to carry in a backpack A second person had to carry the water needed to lubricate the drill bit. I've seen palaeoseimologists use a gadget for very long cores which involved jumping up and down on a platform attached to the corer (again, hefty folks required) - but that was in loose sediments. Good luck! Zoe well, it depends on the rock type and the diameter of your bit. standard 1 inch diameter drillbits, as used for paleomag are about 35cm in length. with those bits, drilling basalts all the way wouldn't be a problem, sediments are more tricky as well as granites and likewise metamorphics. anyway, a lightweight portable rock drill, running on on two stroke petrol should do the job. the best bits can be bought here <http://www.marcrist.co.uk/> <http://www.marcrist.co.uk/> . as far as engines are concerned, try ASC <http://www.ascscientific.com/drills.html> <http://www.ascscientific.com/drills.html> . alternatively, a lighter and perhaps ergonimically superior model can be found here <http://paleomagnetism.geophysik.uni-muenchen.de/images/montafon0007.AVI> <http://paleomagnetism.geophysik.uni-muenchen.de/images/montafon0007.AVI> . Valerian Sven Morgan wrote: Does anyone have exerience using a portable rock core driller that will go approximately 50 cm depth? And still be able to recover the core? Deeper would be better, but 50 cm is the minimum goal. The outcrop is about a mile from the road, so we need to drag the equipment, but it is fairly flat terrain. I would be willing to drag or roll out a generator (or have undergraduates do it). thanks, Sven -- Prof. Dr. Valerian Bachtadse Dept. Earth and Environmental Sciences Theresienstrasse 41 80333 Muenchen, Germany Fon (office): +49 (0) 8921804237 Fax (office): +49 (0) 8921804205 Mobile: +49 (0) 17624098499 Fon (home): +49 (0) 67132710 http://www.geophysik.uni-muenchen.de/people/faculty.php?user_id=valerian -- Sven Morgan Associate Professor Department of Geology Central Michigan University Mt. Pleasant, MI 48859 U.S.A. [log in to unmask] (989) 774-1082 Fax (989) 774-2142