With Facebook set to reveal their Q2 earnings later today, one of the big numbers that people will be looking at is just how much Facebook grew in terms of mobile use over the past few months.

And when those numbers are released, it looks like they will show a big win for Facebook.

According to The Wall Street Journal, who obtained metrics from comScore, Facebook users spent more than double the amount of minutes accessing the site via mobile than they did in Q1. In Q2, U.S. smartphone users spent roughly 225.4 billion minutes on Facebook mobile, compared to just 111.4 billion minutes in Q1.

Specifically, mobile use grew 9.3% in May, and 5.8% in June.

Of course, expanding mobile use is a very important goal for Facebook, who can turn that into more ad impressions. As smartphone use explodes, Facebook needs to see a comparable explosion in its own mobile use – and it looks like today’s numbers will show just that.

The WSJ says that it’s not all rosy for Facebook in terms of mobile, however. They say that Facebook Home, the company’s Android-based mobile platform, didn’t really help in pushing mobile use forward.

Facebook will reveal their Q2 earnings at 2 pm PST today (Wednesday), and you can listen to the webcast here.