I have mined stars for several millions of experience on a regular basis. It is hardly possible to get more than 60k exp per two hour wave, and it would be very hard to get more than 35k from one star. The best experience/hour is actually in the lowest layers, not the highest layers. The low level layers are mined far more swiftly than the high level layers, allowing for more total experience per time unit, albeit the dust being worth less exp individually. This is excluding tags(the experience you get for finding a star), but this would not be a constant factor anyway, so you can't include it in any calculations. Sometimes I would get 30k+ exp from tags in one wave, sometimes none. The average exp per wave I got, tracking multiple stars on my own(chats are horrible if you want experience, loads of freeloaders) was about 50-55k, so I would say a rate of 35-40k exp per wave wouldn't be too far off as an average; excluding tags. Not to mention that you can hardly ever mine properly for two hours straight. The double ore bonus only applies to mining ores(not other stars) and you can only get it once a day, just like the item rewards. It works exactly the same as Varrock Armour, and stacks with it. It lasts for 15 minutes after trading in your stardust after the star is done. Conclusion: Not even close to being a faster method than LRC. P.S. This does show the shift in Jagex philosophy, though. At stars you are practically afking, but it requires some effort to find them and get there first(hence the exp reward for being the first player to get there), but it's worse exp in total than when you are actually doing something click-wise. The work you did was rewarded(getting there first yielded a reward, and afking yielded less exp than mining granite). They were a bonus, but they weren't as good as granite. At LRC you can afk and still get near-granite exp rates. In my opinion, LRC really destroyed mining as a skill. It turned it into another Wc/Fishing and took away the unique aspect of going from rock to rock, or choosing to stay at one rock(star) but getting only half the exp rates for it. With the LRC update you can get the same experience with not even half the work you have to do at Granite or with any other mining method. Of course, Jagex is doing this everywhere. ^^ Every skill used to be slightly different(even Wc and Fishing: the products have different uses and you can influence Wc exp by getting a better axe, there is no such thing as a better net/harpoon), but now the goal seems to be to make everything faster with less effort. x] Good thing I stopped paying them membership fees... =D
