Help, I am ignorant when it comes to meat!

Thanks so much everyone, I ended up cutting most of it off and discarding. It was a sizable amount!

I think you're on the right track here.

The term "rump roast" is not definitive, except it's safe to say it's from the same primal (round) as your usual cuts. In any case, stewing and braising are ideal preparations so no worries there.

Fat = flavor so I'm always hesitant to throw it away but there is definitely a line between unctuous and greasy. If it were me, I'd cut off the heavy fat layer before browning. Fat will render during cooking but if there's too much, you'll just end up skimming it off or, as Chef June suggests, discarding it after it cools. Most diners would prefer you not serve them a big hunk o' fat and that's the real issue as far as I'm concerned. Personally, like Garlic Fiend, I like a little fat, just not too much.

Now, as to discarding flavor, there are water soluble flavors and fat soluble flavors. The water isn't an issue here. The fat will pick up flavor from the other ingredients and that flavor will go overboard along with any excess fat. Better, then, not to introduce too much fat at the beginning.

If you let your stew cool thoroughly andrefrigerate overnight before serving, it is really easy to skim all that fat off the top of the stew. Then reheat. You get all the flavor the fat adds, without having to consume it.

I love a bit of fat in my food; I won't lie :-). I don't think the fat will disappear. I would throw it away if you object to it. I think you will have enough fat from browning the meat. Either way, a pot of homemade stew is ALWAYS good!

Thank you Garlic Fiend, I had feeling. No I already cut it up and browned it. Some of that "rind" of fat separates easily but some does not. I am willing to cut it off and either throw it away or mince it if that will help it render(?) into the broth.

For a roast with a nice layer of fat on one side, I like to roast it in the oven. Is your heart set on making a stew? If not, I would season the roast with your favorite rub, cook it fat-side up. Cook the potatoes you intended for the stew with the meat and they will absorb all that yumminess. Toward the end of cooking, throw in any other vegetables you might have on hand and you end up with a one-pot meal.