I would doubt that any global data on silver values by ore-field would be
of value.In the Mississippi Valley-type ore-fields the distribution of
silver is erratic (see Proc of Yorkshire Geol Soc,last year/this year? for
papers by Dunham et al.;and Ixer and Vaughan in Mineralisation in the
British Isles eds Pattrick and Polya) 1993) and depends upon which
mineralisation event is chosen. This especially applies to the Alston Block
half of the North Pennine Orefield.
Rob Chapman at Leeds and John Mason in Central Wales might help but will, I
hope, confirm this caveat.
Rob Ixer
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