nether_mine.lua

local function place()
    while turtle.getItemCount()==0 do turtle.select(turtle.getSelectedSlot()%16+1) end
    turtle.place()
end
local function placeUp()
    while turtle.getItemCount()==0 do turtle.select(turtle.getSelectedSlot()%16+1) end
    turtle.placeUp()
end
local function placeDown()
    while turtle.getItemCount()==0 do turtle.select(turtle.getSelectedSlot()%16+1) end
    turtle.placeDown()
end
local function sideblocks()
    turtle.turnLeft()
    place()
    turtle.turnRight()
    turtle.turnRight()
    place()
    turtle.turnLeft()
end
while true do
    placeDown()
    sideblocks()
    turtle.dig()
    turtle.digUp()
    turtle.up()
    placeUp()
    sideblocks()
    turtle.dig()
    turtle.forward()
    placeUp()
    sideblocks()
    turtle.digDown()
    turtle.down()
    sideblocks()
    turtle.placeDown()
    turtle.dig()
    turtle.forward()
end