reclaim

-- place against starting quarry block, it will dig out marker, then block beneath it
-- it's not the fastest (because it digs regardless of block presence) but it works

width=31
turtle.up()
turtle.dig()
turtle.forward()
turtle.turnLeft()
for y=1,4 do
  for x=1,width do
    if turtle.inspect() then
      turtle.dig()
    end
    turtle.forward()
    if turtle.inspectDown() then
      turtle.digDown()
    end
  end
  turtle.turnRight()
end