So today we had a soil mechanics lab and performed sieve analysis.  Our soil sample was terrible, actually the whole experiment was terrible (the instructor knocked a portion of one sample into the other while showing us how to separate the sieves "properly").  Our sample specifically had 21 percent of the mass end up in the pan.  How do you calculate for D10 when there is no data available in that range because the soil was too fine and ended up in the pan?  Would it just be considered the size of the last sieve screen?  Thanks.