tunnel2

l = 30
local tCount = 0
turtle.select(2)
turtle.refuel(1)
for i=0,l do
    if(turtle.detect()) then
        turtle.dig()
        tCount = tCount+1
        if( tCount>11 ) then
            turtle.select(1)
   turtle.turnLeft()
            turtle.placeUp()
   turtle.turnRight()
            tCount = 0
        end
        turtle.forward()
    else
        break
    end
    if(turtle.detectUp()) then
        turtle.digUp()
        turtle.up()
        if (not turtle.detectUp()) then
            turtle.select(3)
            turtle.placeUp()
        elseif (not turtle.detect() ) then
            turtle.select(3)
            turtle.place()
        end
    else
        turtle.placeUp()
        break
    end
    turtle.down()
    if(turtle.getFuelLevel()) < 10 then
        turtle.select(2)
        turtle.refuel(1)
    end
end