That alone would probably pay for a mill if you have use of the lumber. Here are the results of four 12' logs out of one poplar tree that was about 24" diameter at the butt end. 106 2x4x12 plus a couple that could be cut back to something shorter.
Out the door price of a 2x4x12 at Home Depot (here, today) is $9.41 That makes that stack worth $996 (again, assuming you can use them)
I figure my cost to saw is around 5 cents/bdft. 8bdft in a 2x4x12 = 40 cents out of pocket to saw (not counting my labor) 106 x .40 = $42.4
$996-42.4= $954.60
Takes me about 4 hours to saw those 4 logs. (one man show, and I'm old

) That works out to $238 per hour of UN-TAXED income. No doubt there are some highly paid folks on here, but for most of us little guys, 238 bucks an hour ain't bad for doing something fun.
No clue as to the size of your 70 logs, but say they just average 100bdft per log.....that's 7,000 bdft of lumber to saw. That 2x4x12 at Home Depot is running $1.18/bdft Those 70 logs could be worth $8,000, and possibly a lot more, depending on size, species, use you could put them too, etc.
My mill was $13,500 in 1991 when I bought it. LT40 with a Briggs 18hp engine on it. The LT35 is the closest model today, basically the same mill, but comes with a bigger hp engine standard (was an option then) ....it runs $16,000. Those 70 logs could pay for half off a brand new mill comparable to what I have and of course, there are a whole lot of more manual mills than mine out there you could spend a lot less than $8,000 on new.