I don't think it is manipulation. These stocks just have too much risk and too little reward for the public to care about them. Costs have gone up and also production is down for some companies making things worse. Until they offer some kind of share buyback or huge dividend increase, i think these stocks will contine to be horrible investments.
Gold companies are making money hand over fist, yet they are priced at the same level as when gold was $800. I think your bearish stance is way too late. The time to be a bear was when gold was at $1900 not seven months later.
It also appears to be that the entire market is trading at a lower PE, not just the miners. The public just doesn't seem to have any risk appetite to invest so the trend for all stocks will probably be lower.