it's possible it is able to be found at hiveworkshop...some of dota's stuff originates from there, otherwise...best bet is to extract the file directly
i haven't checked jetfanginferno's sand models yet, but i think one of those could be it...let me know if it's one of those or not.
no need to import it, i ran into a question exactly like this the other day, there is dust that shoots up with the impale spell (crypt lord spell from Melee maps), that is the dust used dota, most special effects are vanilla effects in dota, but their coding of it is what makes it great
I do know this - xenforo dropped the ball by not keeping the vbulletin reputation comments as a feature. The loss of the Reputation comments data when we switched to Xenforo really was the death knell for the site when it came to all the users that left. I know I missed it so much and I got way less interested in the site when that feature was gone and I run the site.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory