Here are some suggestions for things you should do before you propose a policy:
1) Look at the policy's economic impact. Try using traditional measures, like expected contribution to GDP, or number of new jobs it would create. Exotic measures like "probable aggregated mass of unobtainium in entire landmass of given geology at net present value" may not be the best measure of a policy's economic impact.
2) Based on its economic impact, cost the policy and assess its impact on Crown revenue. If you are unable to find the Crown, DON'T PANIC. The Crown just means the New Zealand Government. There's a good chance that you're sitting in the government RIGHT NOW. Blow the whistle you're wearing around your neck and a friendly helper from the Crown will assess the revenue impact of the policy for you.
3) If the person that arrives is wearing a hard-hat and holding a pickaxe, THIS IS NOT THE PERSON YOU WANT. This person may be a miner, a geologist or a dwarf. The words coming out of his or her mouth are about rocks. ROCKS ARE NOT THE SAME AS MONEY.
4) If the person gives you a report with NEW ZEALAND MINERAL INDUSTRY ASSOCIATION written on the front, BEWARE! Although they both have "New Zealand" in their names, the New Zealand Minerals Industry Association is not the same thing as the NEW ZEALAND GOVERNMENT.
5) For things that affect commercial investment decisions, or have ecological or reputational impacts, you might want to consider the long-term implications. This may be many years, or even many many years. That's very many years.
6) Sometimes, your friendly helper from the government might say that there are bad things as well as good things about your proposal. Sometimes, they call these things "costs", "risks", "downsides", "negative externalities" or "bad things". Listen carefully. If they use any of these words, you should ask them to come closer and explain them to you. Once they are very close, you must to hit them in the head until they stop making any noise. Find the green civil-servant recycling cube on your desk and stuff the body inside. This will safely remove all the bad things from your policy.
7) Remember, New Zealand is a democracy. Therefore, the government debates public policy rationally. Other people who debate public policy are just batshit hysterical insane.