The best thing to do is find some loam and then ask in local chat. THIS IS A HARD QUEST - you need lots of people and even then it does not always work. So chances are many people around you are trying for it too,
i only have SA3 and i just completed this yesterday with one other person... so you dont need lots of people. listen to shepherdmoon -- find a few streets with lots of dirt piles (we used kajuu too) and just keep hitting each pile till you're done. i think it took 3 streets (3 or 4 piles per street) for both of us to finish the quest.
I agree that if you go to Kajuu by yourself you should be able to complete this quest. I tried to do it w/several friends and it worked out for one person, but not the others. If you don't want to do it alone, try w/a single helper. Good luck.
Not sure when you all completed this quest but I tried it recently with someone who did it a while ago and we harvested hundreds of lumps of dirt and only 2 loams. He said that it was way easier when he complete it earlier and thinks it may have been changed and made harder or something. Just a thought. (We were in Kajuu etc doing just what you all suggested, too.)
I just managed to complete it by myself with SA3. It took A LOT of dirt...pretty much the first 15 minutes of consecutive digging yielded no loam, but once it started coming, it came more often and was definitely doable. Good luck!
Miss Larky Lion is brilliant at organising groups for this quest..look her up .. I know she will be more than willing to help...You will find her on my friends list..Good Luck! :-)