Quite simply...it depends.
What is the average diameter of the trees? Average volume/tree?; total merchantable volume?; # of trees?; average merchantable length?; stem/bole quality?; Is the site accessible by logging equipment?
Therefore, it would behoove you to contact a professional forester for an on-site assessment and evaluation to answer some of these logistical questions:
Please contact an ILDNR district forester or a local professional consulting forester to determine whether this patch of "mature" white pine is saleable.
http://dnr.state.il.us/conservation/forestry/
Best of luck!