How is "the original mind" (more of a Zen expression) different, in your view, to Buddha-nature (a more Indian Mahayana way of saying the same thing)?
He says "original mind" and Ajahn Dune Atulo says Buddha-nature (which is a very familiar concept in Thai Buddhism by the way) but they mean the same thing.
I am not trying to reinvent anything here just seeing Thai Forest master pointing to the same thing as Zen and other Mahayana masters, using strikingly similar language, adjectives and similes.
Incidentally Ajahn Chah said this about the Sixth Patriarch of Chan, Huineng, reputed to be the author of the Platform Sutra, which is basically a treatise on the Buddha-nature:
Hui Neng's wisdom is very keen. It is very profound teaching,not easy for beginners to understand. But if you practise with our discipline and with patience, if you practise not-clinging, you will eventually understand. Once I had a disciple who stayed in a grass-roofed hut. It rained often that rainy season and one day a strong wind blew off half the roof. He did not bother to fix it, just let it rain in. Several days passed and I asked him about his hut. He said he was practising not-clinging. This is not-clinging without wisdom. It is about the same as the equanimity of a water buffalo. If you live a good life and live simply, if you are patient and unselfish, you will understand the wisdom of Hui Neng.
Like I've said before - I agree with Tilt that Theravadins don't need to worry
about the Platform Sutra, Zen or Mahayana in general. And I am not trying to convince anybody here that Mahayana is so great or even offers something that Theravadins must have (both of these claims lie outside my knowledge and experience). There is just the fact that outstanding Thai Forest masters have on occasion taught in remarkably similar ways to Zen (Chan) masters and also had some healthy appreciation of their work.
There will of course be many differences as well.