▁set ▁of ▁br ush es , ▁often ▁power ed ▁by ▁a ▁water ▁wheel , ▁which ▁rot ated ▁in ▁the ▁water ▁in ▁order ▁to ▁ag itate ▁the ▁mixture , ▁the ▁result ▁of ▁which ▁was ▁that ▁the ▁heav ier ▁and ▁dens er ▁material ▁- ▁i . e . ▁the ▁ore ▁- ▁t ended ▁to ▁collect ▁at ▁the ▁centre ▁of ▁the ▁pit , ▁from ▁where ▁it ▁could ▁be ▁retrieved . ▁The ▁worth less ▁gang ue ▁was ▁then ▁dis posed ▁of , ▁often ▁by ▁dra ining . ▁ ▁Usually ▁a ▁set ▁of ▁bud d le ▁p its ▁was ▁util ised , ▁with ▁the ▁rich er ▁central ▁depos its ▁in ▁the ▁pit ▁being ▁carried ▁to ▁another ▁bud d le , ▁where ▁they ▁were ▁treated ▁in ▁the ▁same ▁manner , ▁and ▁so ▁on . ▁ ▁Wh ilst ▁the ▁round ▁bud d le ▁pit ▁was ▁the ▁most ▁common , ▁there ▁was ▁a ▁variation ▁called ▁the ▁con ca ve ▁bud d le , ▁which ▁had ▁a ▁con ca ve ▁bottom . ▁ ▁The ▁following ▁detailed ▁extract ▁comes ▁from ▁Mach in ery ▁for ▁Met all ifer ous ▁M ines : ▁A ▁practical ▁treat ise ▁for ▁min ing ▁engine ers , ▁met all urg ists ▁and ▁man agers ▁of ▁mines , ▁by ▁E . ▁Henry ▁Dav ies , ▁C . ▁Lock wood ▁and ▁son , ▁ 1 9 0 2 ▁: ▁ ▁See ▁also ▁ ▁Bud d le ▁p its ▁in ▁D art mo or ▁ ▁Metal ▁min ing ▁ ▁Metal ▁min ing ▁in ▁Wales ▁ ▁References ▁ ▁Category : M ining ▁techniques