cobble

function dig()
  if turtle.detect() then
    if turtle.getFuelLevel() < 10 then
      turtle.select(16)
      turtle.refuel()
      turtle.select(1)
     end
     turtle.dig()
    end
if turtle.getItemCount(1) > 63 then
  turtle.select(1)
  turtle.turnLeft()
  turtle.turnLeft()
  turtle.drop()
  turtle.turnLeft()
  turtle.turnLeft()
 end
end

while true do
  dig()
end