No. It is the proposed mining tax where the Rudd government had the temerity of suggesting all that dirt belonged to all of Australia and those massive profits should be shared with the country. It wasn't even a bill, just raising the topic for discussion.

Then came a very successful (and in hindsight, cheap) media blitz by mining companies against the idea. Which in turn led to the Labor party dropping their leader only two and a half years into his first term.

You're thinking of the Emissions trading scheme, which the opposition very successfully smeared as a tax. It was never a tax. It was a quota system on the amount of pollution each company would make. It was also deeply flawed, because many of the biggest pollutors got a pass on their emissions.

Even if you want to call it a tax, Labor did not win a mandate from the population to go with just their own platform. They were sent in as a minority government, Australians had directed them to work with other parties like the Greens and their policies. You don't get to turn around and call that a broken election promise. They did what we told them to do.