tminer

tPos = 0
tLength = 250


function turnAbout()
  turtle.turnRight()
  turtle.turnRight()
end

function findOrigin()
    turnAbout()
    while tPos > 0 do
      turtle.forward()
      tPos = tPos - 1
    end
    turnAbout()
end

function tryDig()
  while turtle.inspect() do
    if not turtle.dig() then
      turtle.select(getItem("minecraft:cobblestone"))
      turtle.place()
      turtle.dig()
      break
    end
    os.sleep(0.3)
  end
end

function getItem(item)
  for i= 1, 16 do
    local data = turtle.getItemDetail(i)
    if data then
      if data.name == item then
        if turtle.getItemCount(i) > 0 then
          return i
        end
      end
    end
  end
  return 1
end

function checkTunnel(digStage)

  turtle.select(getItem("minecraft:cobblestone"))

  if digStage == 0 then
    if not turtle.detectDown() then
      turtle.placeDown()
    end
    turtle.turnLeft()
    if not turtle.detect() then
      turtle.place()
    end
    turtle.turnRight()
  elseif digStage == 1 then
    if not turtle.detectUp() then
      turtle.placeUp()
    end
    turtle.turnLeft()
    if not turtle.detect() then
    turtle.place()
    end
    turtle.turnRight()
  elseif digStage == 2 then
    if not turtle.detectUp() then
      turtle.placeUp()
    end
    turtle.turnRight()
    if not turtle.detect() then
      turtle.place()
    end
    turtle.turnLeft()
  elseif digStage == 3 then
    turtle.turnRight()
    if not turtle.detect() then
      turtle.place()
    end
    turtle.turnLeft()
    if not turtle.detectDown() then
      turtle.placeDown()
    end
  end
 end

function moveForward()
    if not turtle.forward() then
        tryDig()
        turtle.forward()
    end
end

while tPos < tLength do

  if turtle.getFuelLevel() < 10 then
    turtle.select(getItem("minecraft:coal"))
    turtle.refuel()
  end

  tryDig()
  checkTunnel(0)
  turtle.up()
  tryDig()
  checkTunnel(1)
  turtle.turnRight()
  moveForward()
  turtle.turnLeft()
  tryDig()
  checkTunnel(2)
  turtle.down()
  tryDig()
  checkTunnel(3)
  turtle.turnLeft()
  moveForward()
  turtle.turnRight()
  moveForward()
  tPos = tPos + 1

  if tPos % 5 == 0 then
    turtle.turnLeft()
    tryDig()
    turtle.select(getItem("minecraft:torch"))
    turtle.place()
    turtle.turnRight()
  end

end

findOrigin()