The profile of the average bitcoin miner has changed dramatically over the course of the currency's short history.

Once the pursuit of hobbyists with powerful CPUs (and later GPUs), mining is now a highly competitive business performed on an industrial scale.

But what is life like inside one of these power guzzling giants? Blogger Bitsmith found out first-hand on a trip to a one of the world's biggest facilities at a mystery location in China. Check out the scenes he witnessed in the gallery below:

As more mining firms pile in, bitcoin's network difficulty is soaring higher and higher. Additionally, the price has been struggling to break beyond $600 for several months now, so the days of near-instant profit are long gone.

When these factors are combined, more powerful – and, crucially, more power efficient – hardware is needed for miners to make a profit.

The resulting 'arms race' is clear to see from these pictures: barely dry cement, giant racks of hardware and a mounting pile of empty cardboard boxes sat in a warehouse that took just fifteen days to construct.

Here, at least, these aggressive tactics appear to be paying off. With an output of several petahashes, staff estimate that the centre accounts for around 5% of the entire bitcoin network's mining power.

Pictures republished with permission. View Bitsmith's original post here.