The numbers show last year was just as bad as we felt it was. According to the latest PwC report, Mine 2014: Realigning Expectations, a study of the world’s Top 40 mining companies shows that last year saw a record $US57 billion bill for impairment charges.

On average, the profits of these companies plunged by 72% to just $US20 billion, the lowest in a decade (and do I need to remind you what revenues were like in 2003?)

But, before going on to examine the PwC report, the figures have to be considered in light of two points.

One, the year 2014 is going to prove another tough one. Some of the Top 40 are doing business in troubled sectors, gold being the obvious one with Barrick, Randgold, Goldcorp and Yamana Gold among them.

The rare earths sector is a mess, which will be still causing concern at Inner Mongolia Baotou Steel Rare-Earth High-Tech.

And, how will Cameco be faring with uranium spot at $US28.25/lb? Even though it is selling at much higher contract prices, uranium is still a very depressed sector?

The other question: what if the present malaise, as most likely, persists into 2015?

Just when the market seems to be working up steam, along comes something to knock it back, as happened last night to base metals on the back of news of allegations about fraudulent warehouse receipts for metals at the port of Qingdao.

So, when reading what follows, consider the implications for the present year and 2015.

Of the Top 40, only four saw an increase in their market capitalisation last year, Fortescue Metals Group being the only Australian company in that select group.

Overall, total market cap dropped by 23% to $US958 billion – that 23% represents $US280 billion wiped off the sector’s wealth.

Costs were kept under reasonable control, being up only an average 4%. But net debt soared 42% to $US249 billion (partly due to cheap finance), but revenues rose just 1%.

Shareholders did not miss out. Overall, dividends rose by 5%. But, here is an extraordinary statistic: tax rates soared from 26% on average to 60%, partly due to increasing demands from host governments (which shows that at least some countries know how to design a mining tax that works, even if Canberra doesn’t).

Under the heading “Sleepless nights for the Top 40 CEOs”, the PwC report recalls that in the firm’s study covering 2012 it showed that a quarter of the Top 40 changed leaders.

“However, in 2013 the Top 40 CEO was still awake at night. Another seven (18%) of the Top 40 changed leaders and almost all of them were in the Top 20 companies. This means almost half of the companies that have been in the Top 40 over the past two years have hired a new CEO since 2011 – an incredible statistic”, the report continued.

The average tenure at the big end of the mining business is 6.5 years. Still, that’s 6.5 years at truly wondrous salaries and hurt feelings more than compensated for at the end of their time by golden handshakes that make Lotto division one prizes seem derisory by comparison.

The ups and downs have seen some companies go in and out of the Top 40 list depending on their variable fortunes. All five companies dropped out in 2013 were gold miners.

Coming back into the list after short absences were Consol Energy – which switched from coal to gas – and Cameco. After longer absences, Sumitomo Metal Mining and Randgold were back as well.

Two new ones were Saudi Arabian Minerals with its exposure to the kingdom’s gold, base metals, phosphates and aluminium, and Russian diamond miner Alrosa which joined after an IPO.

Fortescue and Newcrest Mining were the only two purely Australian companies to rank, with BHP Billiton and Rio Tinto being regarded as British-Australian hybrids.

Canada was the sector leader with eight companies in the Top 40, followed by China with seven – although its BRIC mates just scraped in, Russia and India with two each and Brazil one, being Vale of course.

But the financial constraints had to show up somewhere, and that somewhere was exploration – overall, spending in that area dropped by 30%. PwC, looking at announcements so far in 2014, estimates exploration outlays will be down another 10% this year.

Can we deduce from this another supply crunch a few years out? And then off we go again.