I think for a stock to be added to the GDXJ it needs to be over...

I think for a stock to be added to the GDXJ it needs to be over a US$150M but also have a couple of consecutive quarters of daily volume above a certain number (US$1Million from memory).

MML only trades small volume so could struggle to get back in soon.

DRM might be a potential candidate but I imagine there are a lot of gold stocks who are starting to look like candidates for addition to the GDXJ.

In terms of effects on share prices, what tends to happen is front-running by a lot of hedge funds etc prior to the announcement of stocks to be added/deleted from the indices (the addition/deletion announcement happens a week or more before the actual rebalance and is published by Van Eck somewhere).

There is so much front-running of these rebalances that the potential gains are harder to get. A lot of funds got burnt last quarter when they shorted NST/EVN before the rebalance only to buy them back higher on the Friday rebalance. Plus the fed meetings tend to coincide with the rebalance dates and make gold more volatile.