Can't answer for him, but around here (N FLa) lease truck is gonna run $150-200/hour. If hes paying for the gravel, and your paying him, hes going to mark that up atleast 18% over the mines price; plus truck rate; plus profit. So, figure 60 minutes each way, some time on your site; call it 2.5 hoursx150; plus $17/ton; plus 18% mark up; plus 18% profit;
$375 trucking; $240 in material, mark up, profit; $615. Funny part is, thats $615 for 10 tons or maybe $815 for 18 tons with a full sized truck. Thats why a 10T truck isnt really efficient for bulk material delivery. What it does do, is allow you to haul your own small amounts, for contracted work, on your schedule.
I dont speak for the OP, but im guessing if he has a job that requires 80-120 Tons of material delivery, even owning a truck, its more cost effective to hire than, mark their price up, and make the money on spread/finish