I fish a Smallmouth only quarry pond often, But as far as I can tell It's only forage is bluegill tiny ones at that, I've layed crawfish traps and used bobber and worms (surprisingly worms and gills don't catch nearly as much as lures would)
1. Is this an unhealthy pond? I catch probably 5-15 5 inch bass a day, acording to my friend 5 years ago the average was 12 inch, It's not my pond but I really don't want to see this pond end up starving itself Should I add crawfish or some other baitfish? (Atm even the quarry people themselves don't know who exactly owns it)

 

2. What would the best lures be for this? It's a silt/rock bottom seems to be 50+ ft deep in the middle but quickly rises to about 5-10 ft, I see huge bass jumping at birds but they are beyond casting distance, My main success in this quarry is Wacky senkos, jerkbaits and spooks. biggest I've caught is about half of what I've seen pulled out of this pond a few years ago (my friend has pulled 5 pounders I've only seen and caught 1 1/2 pounders)

If your friends are catching 5 pound smallmouth out of this quarry pond, I'd ask them what they're doing. Obviously the fish aren't starving if they're able to grow to 5 pounds. Playing "bucket biologist", is rarely the answer to finding the right balance to growing bigger fish. You might see if there's any programs offered through the DNR or local colleges that will check the health of your water and the fish in it. 

Catching 5 pound smallies, quarry seems healthy.

Ontario Canada, the pond freezes for a few months so it must  have a spring for water source and run off a small stream.

The spring provides warm water 50-60 degrees year around.

Smallmouth bass #1 prey is crawdads, bait fish are secondary. Large insects like dragon fly and Mayflies and their nymphs, all sorts of terrestrial critters. 

Smallmouth are roaming bass on the move unlike largemouth that tend to be object oriented. I would get a kayak.

Try using a single spin spinner bait, noisy top water lures and Ned rigs. Also larger size plastic worms and jigs at night.

Tom

nm

I would catch a couple of Bluegills. Keep alive  on a thin piece of string tied to a STOUT pipe in the ground. get a 2 " red & white float. Hook the sunny threw the upper lip only with a big hook with a crushed down barb.  Heave hoooo.

Have something to remove the barbless hook . Very long nose plier or those plastic tools with each end having a slit in the ball. 

 

The bass will race to that easy sunny. 3 feet from the bouncing ball.   Enjoy