Concrete

while true do

if turtle.getItemCount(1) ~= 0 then
    turtle.place()
    turtle.select(2)
    turtle.dig()
    turtle.select(1)
else
    sleep(0.1)
end

if turtle.getItemCount(2) == 2 then
    turtle.select(2)
    turtle.dropUp(1)
    turtle.select(1)
    end