a sandpile on a graph is an integer-valued function on the vertices. it evolves according to local moves called topplings. some sandpiles stabilize after a finite number of topplings, while others topple forever. for any sandpile $s_0$ if we repeatedly add a grain of sand at an independent random vertex, we eventually reach a "threshold state'' $s_t$ that topples forever. poghosyan, poghosyan, priezzhev and ruelle conjectured a precise value for the expected amount of sand in $s_t$ in the limit as $s_0$ tends to negative infinity. i will outline how this conjecture was proved by means of a markov renewal theorem.