stripmine.lua

upDown = {turtle.down, turtle.up}
digUpDown = {turtle.digDown, turtle.digUp}
detectUpDown = {turtle.detectDown, turtle.detectUp}

function selectItem(item)
    ruta = turtle.getSelectedSlot()
    stop = ruta % 16 + 15
    while ruta ~= stop and (turtle.getItemDetail(ruta) == nil or turtle.getItemDetail(ruta).name ~= item) do
        ruta = ruta % 16 + 1
        if turtle.getItemDetail(ruta) then
            print(turtle.getItemDetail(ruta).name)
        end
    end

    if turtle.getItemDetail(ruta) ~= nil and turtle.getItemDetail(ruta).name == item then
        print("item found")
        print(turtle.getItemDetail(ruta).name)
        turtle.select(ruta)
        return true
    end
    print("item not found")
    return false
end

function digGravel(dig, compare)
    if selectItem("minecraft:gravel") and compare() then
        while compare() do
            dig()
            sleep(1)
        end
    else
        dig()
    end
end

for i = 1,64 do
    digGravel(turtle.dig, turtle.detect)
    turtle.forward()
    for j = 1,8 do
        if i % 6 == 0 and j == 7 and selectItem("minecraft:torch") then
            turtle.turnRight()
            digGravel(turtle.dig, turtle.detect)
            selectItem("minecraft:torch")
            turtle.place()
            turtle.turnLeft()
        end
        digGravel(digUpDown[i%2+1],detectUpDown[i%2+1])
        while not upDown[i%2+1]() do
            sleep(0.5)
        end
    end
end

turtle.turnLeft()
turtle.turnLeft()

for i = 1,64 do
    turtle.forward()
end

for i = 1,16 do
    turtle.select(i)
    turtle.drop()
end