Does coal industry have a future in Wales?
The Gleision mining tragedy in the Swansea Valley which killed four men almost a year ago was shocking.
It was also a reminder both of the dangers of an industry that once employed tens of thousands in Wales, and that coal mining still exists here.
It may come as a surprise to many that about 1,200 people still work in the coal industry in Wales.
One big advantage is that there are still huge reserves under the ground but, as ever, the issue is the cost of getting at it compared with the cost at which you can sell it.
Another advantage for the mines in south Wales is that they have two massive consumers of coal on their doorstep: the Tata steelworks in Port Talbot and the coal-fired power station in Aberthaw. Between them they buy about 80% of all Welsh coal.
Opencast mining dominates. For the three months to the end of June, 94% of all Welsh coal came from opencast sites, the remainder from drift mines.
The two largest opencast sites are at Ffos y Fran in Merthyr and at Tower Colliery, the site of the last deep pit in Wales in the neighbouring Cynon Valley. They are among the top three largest opencast sites in the UK.
Both of them aim to mine some 1m tonnes of coal a year for their limited lives which, in the case of Tower, is for the next seven years.
Despite producing a small proportion of Welsh coal, the four underground pits in Wales employ nearly 600 people.
The vast majority work at two pits in the Neath Valley: Unity and Aberpergwm.
There are two drift mines of a similar size to Gleision which have licences but none are in production at the moment.
Between them all, coal production in Wales rose by a third in the first six months of the year. It is the only place in the UK where there has been a rise.
Scotland still produces more coal than Wales, but everything comes from opencast while the bulk of English coal still comes from the underground pits in the north of England.
Producers say current prices are making life difficult. Due to a surplus of coal in the US, the price has dropped significantly to just over £50 a tonne which is squeezing margins, and is one of the reasons why the the owners of the Aberpergwm mine say 90 jobs out of its 350 are currently under threat.
The Gleision tragedy threw a spotlight on the nature of some of the small drift mines that were once dotted around Wales, but the reality of modern day opencast mining is as far removed as you get can from a pit like Gleision.
Rather than a handful of men working in close confines about 90m underground, at a site like Tower there are some of the largest earth movers in the UK digging a hole 180m on the surface.
However, even though modern methods and machinery have made the industry safer on the whole, the events last year in the Swansea Valley showed that there is always danger in an industry like coal mining.