The mining tax has been called many things by the mining industry. It was “sovereign risk”, we were told, even as Australia was ranked by foreign investment analysts as the world’s best place to invest in mining for four years in a row. It would deter mining investment, we were told, even as mining investment surged to record highs far beyond any previous point in Australian history and Australian mining company stocks outperformed those of foreign miners. And we were told it was unconstitutional as well.

That turned out to be wrong, too. The High Court disagreed, and today dismissed the arguments of Andrew Forrest’s lawyers.

Then again, the government repeatedly claimed the mining tax would generate significant revenue. That, too, turned out to wrong — and the government repeatedly scaled down its forecasts.

That will change, however. If commodity prices remain above their long-term historical average, then the mining investment boom that is now tailing off will see a huge increase in Australia’s mineral production and a surge in mining company revenues that will no longer be offset by their investments in new capacity. Both company tax and the mining tax will generate substantial additional revenue from what may become Mining Boom Mark 3 — again, depending on how commodity prices fare.

The Coalition has promised to repeal the mining tax. More sensible policy would be to leave it in place and, if and when it starts to produce significant revenue, to direct it all into the Future Fund or other long-term Commonwealth investment vehicles, well away from recurrent expenditure. And that goes for Labor as well.