Apart from google maps and google earth you can also use multimap.com which is very good too.They've been updating their imaging recently so some of it is either the same or perhaps newer than google, that said some of it is still quite old (ie. at least 4-5 years old).Claymore_wam wrote:Which satellite sites do you use, musikman? I know of Google Earth but can't think of any others.
RE:Quarries. I'm not clear as to why there would be clay pools at sand and gravel quarries? Surely they'd be full of sand and gravel wouldn't they? Also, aren't these places all locked up and with cctv or security guards or whatever, or are they just left wide open 24/7?
C_W.
Another site to try is maps.live.com although I believe multimap uses exactly the same imagery.
Clay ponds/pools appear at virtually every sand/gravel quarry because an awful lot of water is used to extract the gravel from the earth and it's often in amongst thick/hard clay or earth so the water is used to separate the gravel from the clay and the run-off from this is stored in huge settlement ponds somewhere on the site.The very fine clay particles just sit there suspended in water and over time the pond develops different consistencies of clay in different parts of the pond so some of it (usually the biggest particles) turn into a hard baked surface that's hard enough to walk across without even breaking the top, whilst other areas of the same pond you could easily sink into upto your chest in very fine,soft clay (although beware sometimes the surface may look hard enough to walk on but actually it will easily collapse under feet and you can find your whole leg's been swallowed up to above the knee in a second!).
Where the age of the satellite imaging is crucial is that these ponds can sometimes disappear rather quickly, depending on what the quarry wish to do with the pond.Some can last for ages (ie. years) so long as it's still in use whilst others are abandoned to nature and dry up and grow over in a matter of months so the mapping might just merely tell you where a pond used to be.That said, if the quarry's still operating they may well have started a new pond elsewhere on the site so that's when to keep eyes peeled on the site for another one that's too recent for the mapping.
In some countries numerous noxious chemicals may still be used to separate gravel from clay so these settlement ponds may be genuinely dangerous but the UK is tied into EU regulation that does not permit their use anymore so environmentally-friendly methods are generally used here as elsewhere in the EU which ensures the quarry sites can be returned to nature safely without harming the local ecology once all gravel deposits have been exhausted. Most clusters of small lakes you see just about anywhere were most likely once quarries and gravel pits and many are now used for watersports/fishing/swimming etc., that couldn't happen if harmful chemicals were used at those sites.
The same cannot be said for some other quarrying operations (limestone/iron ore/gypsum etc.) as hard stone cutting usually makes use of powerful chemicals to speed up the rock-breaking so the run-off from these operations is not something I for one would choose to come into contact with, unless someone else knows more about this and can say categorically that they are as clean as gravel quarrying.
Regarding security etc. it would seem that levels of security can vary widely depending on where the quarry is. For example, in an area of higher crime and numerous break-ins you're likely to find a quarry in that area with plenty of warning signs including dogs/cctv/round-the-clock security guards as they guard the expensive machinery,earth movers and what not. Some of this is bluff but some of it isn't. You can usually tell if the quarry entrance is lit at night, if it has very high inpenetrable fencing and if there is a hut that is clearly in use ( lights on after operating hours) it's probably a good idea to steer clear.
On the other hand, in a remote area of lower crime the quarry can be quite open or at least have the minimum legally required fencing-off that makes them a possibility outside operating hours (usually posted at the quarry entrance) and there are some quarries that have bridleways and footpaths that go right through them and are rights of way that were there before the quarrying started there.Some quarries are duty-bound to keep these rights of way intact so you may walk up one of these paths quite within the law and find a quarry all around you and some can be surprisingly open sites too!
Once you have seen enough different sites you will get a feel for what looks good and what looks like it's worth giving a wide berth, there's not really any rhyme or reason to it in that regard other than what your own experience tells you.
Btw, just about all settlement ponds have KEEP OUT signs (and sometimes THIS IS NOT A PLAY AREA) around them and most likely barbed wire too to stop the chances of children playing around or worse in them as this deep clay is treacherous stuff for the those not familiar with it's inherent dangers.It's not hard to see why little ones can get into great difficulties very quickly in one of the these pits so it's definitely best that way and,besides,it's a legal requirement.
