I listened to a news report which suggest the elephant sanctuary was making 40million baht profit per year. they charge something like 2000b entry for foreigners and had plenty of people there throwing water over the elephants - which might have been an additional fee.
The sanctuary also receives large amounts of donations to 'help' the elephants.
It cost about 14mil baht to set up.
It was all in Thai so not sure if this is correct to not.