Friday's close on the sharemarket was probably the best immediate reaction to the new mining tax deal announced earlier in the day.

There was a lot of market talk and immediate number crunching, but not much foresight; some scepticism about the relatively small drop in tax revenues (around $1.5 billion a year), but also recognition that we won't know much more until the final shape of the tax (and the legislation) is hammered out.

That won't come until after the election, if the Labour Government wins; it won't if the Opposition wins.

Today there will be a lot of investors receiving reports from broking houses and their analysts, plus the big fund managers getting reports from their in house analysts and external advisers, about what it means for the likes of the mining stocks.

For the banks, retailers and others, it means very little.

Tomorrow's interest rate meeting at the Reserve Bank has more importance to the broader market than the mining tax issue.

As well there's the very important point of where market prices for iron ore coal, oil and to a lesser extent gas, will be from 2012-13 onwards.

No one knows, they could be higher, they could be around where they are now, they could be lower is the world economy slides back into a low growth "recession" and stays there for a while.

Even though we don't know the details, there is a case of BHP, Rio Tinto and other companies to outline in broad detail what they think the impact could be.

It would help inform the market as a whole.

After an early rise Friday morning off the back of the tax deal settlement, investors got more cautious as the day went on and by the close there were no gains to speak of.

The big miners broadly welcomed the new tax (ha!), the smaller ones moaned that they got nothing and most investors looked at the imminent release of the US June jobs report Friday evening, the long weekend in the US and decided to play it safe.

The market was up just 1-2 points for the major indices

Rio Tinto added just 20 cents to $65.30, BHP Billiton lost 2 cents to $37.09 and Fortescue Metals added 8 cents to $4.08.

Macarthur Coal lost 18 cents to $12.12, Iluka Resources lost a cent to $4.67 and OZ Minerals was steady on $1.00.

Energy stocks were also affected by the changes to the mining tax, with the current petroleum resource rent tax regime extended to all onshore oil and gas projects including coal seam gas, but at a 40% tax rate.

Woodside shed $1.03, or 2.5%, to $41.00, Santos 14 cents to $12.22, Oil Search 6 cents to $5.37.

But Origin Energy added 21 cents to $14.83 and Arrow Energy 6 cents to $4.86 That's irrelevant given the impending Shell/PetroChina takeover).

Gold stocks fell heavily, in line with the Thursday night drop in the gold price.

Merger partners, Newcrest Mining lost $1.13, or 3.2%, to $34.24 and Lihir Gold shed 13 cents, or 3%, to $4.20.

All through the debate it's been the almost continual fall in commodity prices that have had the greater impact on share prices than the tax.

In fact Rio and BHP have both out performed their offshore rivals in the past two months: the falls in their share prices have been much smaller than the falls in prices of the likes of Anglo, Xstrata and others.

It has been the iron ore and coal interests (especially of BHP) that have helped cushion the slide in their share prices.

Odd how both companies never pointed to that factor, nor did the mining industry as a whole.