Use the MAL to find the treasure. Keep in mind the following:
The treasure is found in a random location (anywhere in the zone) for every person in your group. If you're in a group, you will be heading to different treasure locations for each group member in order to complete this step.
The MAL gives you two basic readings: a directional color and a distance strength. The directional colors are: Red = directly behind you, Orange = somewhere behind you, Green = straight ahead, Yellow = somewhere in front of you. So when you're heading the right direction, the MAL will glow with a green hue. The strengths for distance in order from far away to right on top are faint, dim, dull, bright, and blinding. When you're right on top of the treasure, the MAL will glow with a blinding greenish hue.
Sometimes even a single step in a different direction can change how the MAL glows. If you think you're really close to the treasure and then suddenly seem to be far away, try stepping backwards a number of steps and try again. It takes a little bit of tweaking to find the treasure.
Once the MAL glows with a blinding greenish hue, use the MPMDD to dig up the treasure.
Return to Heron Cogcarrier ( -1056, -146, -634 ) /waypoint -1056, -146, -634 for your reward.
Addendum: I have made a different experience. When you're close, Yellow means you should turn right. Red means you should turn around, orange means you should turn left, green means it's ahead.