A simple ComputerCraft pinwheel mining script.

pinwheel.lua

-- Allaryin's pinwheel miner
--
-- v1 - Dec 14, '12
-- v2 - Dec 15, '12 - attempts to deal with gravel
-- v3 - Dec 16, '12 - improved gravel & refueling

-- instructions
--   fuel goes in slot 1, torches go in slot 2
--   place turtle on left of 2x2 tunnel to be dug
--   run script :)

print("pinwheel start @ " .. os.time())

-- check torch level
--   18 torches used

if turtle.getItemCount(2) < 18 then
  print("! insufficient torches")
  exit()
end

-- check fuel level
--   46 fuel per arm length +1 is used
--   for a total of 277

while turtle.getFuelLevel(1) < 277 do
  print("- refueling")
  turtle.select(1)
  succ = turtle.refuel()
  if succ ~= true then
    print("! insufficient fuel")
    exit()
  end
end

print("fuel = " .. turtle.getFuelLevel())

-- mine the 2x1 block in front of the turtle
function mine()
  turtle.dig()
  -- try to go forward
  if turtle.forward() == false then
    clearGravel()
  end
  turtle.digDown()
end

-- clear some gravel
function clearGravel()
  repeat
    turtle.dig()
    sleep(0.25)
  until turtle.forward() == true
end

-- dig
while turtle.up() == false do
  turtle.digUp()
end

for len = 1,6 do
  -- main hallway
  mine()
  turtle.turnRight();  mine()

  turtle.turnLeft();   mine()
  turtle.turnLeft();   mine()

  turtle.turnRight();  mine()
  turtle.turnRight();  mine()

  -- dig arm
  for arm = 1,18 do
    mine()
  end

  -- return, placing torches
  turtle.select(2)
  for torch = 1,19 do
    turtle.back()
    if (torch % 8) == 1 then
      turtle.place()
    end
  end

  -- get ready for the next step
  turtle.turnLeft()
end

-- reset
for k = 1,19 do
  while turtle.back() == false do
    turtle.turnLeft(); turtle.turnLeft()
    turtle.dig()
    turtle.turnLeft(); turtle.turnLeft()
  end
end

turtle.turnLeft()
while turtle.down() == false do
  turtle.digDown()
end


print("fuel = " .. turtle.getFuelLevel())
print("pinwheel stop @ " .. os.time())