I believe Coolies are an Australian breed. I have a friend who owns two of them, but they are pets, not working dogs. In build, they are a bit between an Australian Cattle Dog and a Kelpie, and about the size of a BC. Both of the ones I know are extremely affectionate with people, although quite standoffish with other dogs. They can be quite prone to barking, though less than an Aussie. Both are intelligent and trainable. I know one (not my friend's) who is an agility champion and obedience champion.
The ones I know are both merles, both shorthaired.
This is Dougie, one of the Coolie's my friend owns. She rescued him from a truck driver who left him chained in a yard all day, and fed him once a week when he got back from long distance driving.