Sentence:  This [ore mixture] was <WSD>bucked</WSD> or cobbed down to a 'peasy' size (i.e. the size of a pea) or less, using a flat-bottomed bucking hammer, and then riddled into coarse peasy and finer (sand-sized) 'smitham' grades.Webster 1913 
Meaning of the word marked with <WSD> tags:  To break up or pulverize, as ores.