At the pumping station there is an orb on the windmill that is to the right and forward from when you first go through the north gate, it is tricky to get to but you can get to it if you do a roll jump from the cliff to the right of the green things that attack you. There is also one in the water on the right side of the bridge past the blown up water tank (it is in the corner).

At the beginning of the game when you're in the process of escaping from prison there is one behind a control panel where the guards are shooting at your from the lower level, there is also one a bit earlier above a control panel (you have to jump fairly high) and just before you bust out of the prison and meet Kor there is an orb in the water behind the crates of health and one at the top of the pile of boxes which you need to jump up.

After you get the precursor stone at the Baron's death scene there is an orb to the left of the ramp(or stairs whatever you consider it to be).

In the artifact level when you are going to go and get the vibrating crystal at the beginning of that there are 2 red metal heads there and there are 2 grind bars, well they may look like grind bars but you can actually climb up them and at the top of the right grind bar behind a tree there is 3 orbs, behind a tree on top of the left grind bar there is another 3 orbs but there is an passage (on the left one), go through it and you will find many more orbs as you go through the passage, ignore the right turn off which has a metal head in there, just keep going straight ahead until you come to the eco lake at the time of doing this mission you wont have the jetboard so just go back and get on with the mission, but come back to that spot after you get the jet-board and hover over the eco lake and you will see more orbs on land, just before you go into go and get the vibrating crystal stand to the right of the little platform that you jump onto to get to the crystal and press R3, look down and you will see an orb hovering on top of that little part of the eco lake, calculate where you need to jump and do it, it doesnt matter if you die. 

Just before you take the glass lense artifact, swim in the water to the far left, there is an orb. 

On the metal head scout level, in the big lake hover around on your jetboard and you will see many orbs IN the water.

At the dig, it is best to get this orb when it is infested with metal heads instead of krimzon guards, i cant remember exactly but you have to go across a little lava river and go up a very steep hill at the top there is an orb once at the top you see the lava waterfall, i mean the lavafall. Once you are on top of the wooden thing that keeps rising as you press buttons instead of jumping up to keep going jump to the  left onto the ground and follow it, it rises up fairly high but at the top there is an orb.
At the Tomb of Mar just as you enter it after Samos and all that get arrested there are two orbs, one to your left behind a statue and one to your right behind a statue.
there are plenty more out there you just have too be looking