You brought up a good question and I have the answer. My lawers set down Nov 1, 2012 with DCNR's lawers in Harrisburg to talk about the laws on Treasure Hunting in Pa. and this was one of our questions. Ted Boriski from the Mineral section said there is a lot of people now that the price of gold has gone up that are paning for gold and it is OK and you get to keep it all. This falls under the hobby law. Treasure Hunting is a hobby to if you have a hand held detector and you go into the earth a few inches. If someone does like we do and go with bigger drilling equipment and GPL's and Radar and Long Range Locators on a bigger scale then we have to be bonded. With a bond we have to tell them were we are and when we are in the woods. If you pan in Pa. it is good to let them know were you are to show good trust but if you get bigger with equipment and dig then you need a bond. They said gold has been found in all parts of Pa. I hope this helps.
You can use a sluice too... just nothing motorized though. If you want to use a dredge, you need to apply for a permit. Here is a link to the DEP fact sheet (right hand column). Hope this helps!