Turtle Snow Generator (computercraft)

print ("Snow generator & crafter")

j = 0


while true do

    if j % 20 == 0 then
        for i = 1, 16 do
            turtle.select(i)
            turtle.dropDown()
        end
    end

    j = j + 1

    totalSpace = 0
    totalMined = 0
    turtle.select(1)

    for i=1,4 do
        totalSpace = totalSpace + (16 - turtle.getItemCount(i))
    end

    while totalMined < totalSpace do
        if turtle.dig() then
            totalMined = totalMined + 1
        end
    end

    turtle.select(5)
    turtle.dropDown()
    turtle.select(6)
    turtle.dropDown()

    turtle.select(3)
    turtle.transferTo(5)
    turtle.select(4)
    turtle.transferTo(6)

    turtle.craft()

    turtle.dropDown()
end