Effective mining tax rates across countries

Comments on Dennis Shanahan “Kevin Rudd to backflip on mining tax rate”, 27/05/2010, http://www.theaustralian.com.au/business/in-depth/kevin-rudd-to-backflip-on-mining-tax-rate/story-fn5eo6td-1225871786155

If what the graph (copied from the article and attached below) shows is true, it means the effective tax rate on mining is already higher than most large producers for mineral and at the middle for petroleum, bearing in mind that some large oil producing countries are not shown.

Then what is the point to have the RSPT and why does Australia move to an even higher mining tax country?

While minerals are immobile, mining production is capital intensive. So why did those leading economists who issued a statement yesterday note this? Professional negligence, or economic incompetent?