Tunnel Miner

function forward()
    if turtle.getFuelLevel() ~= "unlimited" and turtle.getFuelLevel() < 1 then
        turtle.refuel()
        print("Refueling...")
    end
    turtle.dig()
    local x = turtle.forward()
    if (x == false) then
        return forward()
    end
end

function go(dist)
    i = 0
    while (i < dist) do
        i = i + 1
        forward()
    end
end

function goAndPlaceTorches(dist)
    i = 0
    while (i < dist) do
        i = i + 1
        forward()
        if (i % 10 == 0) then
            turtle.select(16)
            turtle.turnRight()
            turtle.place()
            turtle.turnLeft()
        end
    end
end

print("Tunnel length: ")
local length = tonumber( read() )
local i = 0

print("Starting...")
-- first tunnel
go(length)
turtle.turnRight()
turtle.dig()
turtle.forward()
turtle.turnRight()
goAndPlaceTorches(length)
turtle.turnRight()
turtle.dig()
turtle.forward()
turtle.turnRight()
turtle.digDown()
turtle.down()
-- second tunnel
go(length)
turtle.turnRight()
turtle.dig()
turtle.forward()
turtle.turnRight()
go(length)
turtle.turnRight()
turtle.dig()
turtle.forward()
turtle.turnRight()