2010/11/22 Richard Moss <[email protected]>: > on 05/11/2010 Martin Koppenhoefer wrote >>> On 11/5/10 11:05 AM, Richard Mann wrote: >>>> Gravel/sand/clay come from river beds, generally. Quarries are when >>>> you blast half a hill away. >>>> But I'm not an engineer... >>> >>> gravel around here comes from excavating in the sides of hills >>> that are actually piles of debris left by glaciers in a previous ice >>> age.
>>could a clay pit that is used only to excavate clay be put under >>quarry, or would that be missleading? I know that these are all >>open-cast mines, but the wikipedia entry for quarry seems somehow not >>precise enough when it comes to delimiting the usage. > I am an engineer :-) (though not in the mining industry) > My Penguin Dictionary of Civil Engineering has > "quarry: An open pit from which building stone, sand, gravel, mineral, or > fill is taken" > This looks a wide enough definition to include clay. Thank you very much, if they publish a dictionary about civil engineering we might suppose that this information is quite reliable I guess ;-). Sand is used for grain sizes from 1/16 mm to 2 mm, silt would be 1/256mm to 1/16 mm and clay is below silt (smaller then 1/256 mm or 4 µm (2 µm)). As they speak of "fill" and fill is just defined by it's usage AFAIK (comprises all smaller grain sizes), we might not have a problem by using quarry for clay pits as well (subtagging quarries as clay_pits). cheers, Martin _______________________________________________ Tagging mailing list [email protected] http://lists.openstreetmap.org/listinfo/tagging
