If you have owned your land for several generations or have purchased it recently without having heard mention of previously sold minerals you could well be the proud owner of natural resources that are highly sought after by many companies who wish to exploit the land and gain access to the minerals beneath it.
If you are in a comfortable position financially it would be wise to hold off on the sale of your mineral rights until such time that the price of the resources is at a peak in the international market. This will help you get the most out of a deal to sell mineral rights on your land. It is always wise to seek professional advice in this matter by either contacting a geological society, which many local governments have and an attorney who is experienced in this kind of transaction.
The general type of deal you can expect to receive for your minerals is to get an upfront payment and a royalty bonus on the minerals that are physically extracted from the land. Be warned though that sometimes companies will buy the minerals on your land but not actually process them for many years until they deem it time and are able to make a profit from the operation. There is a way around this by creating a lease structure rather than outright selling the rights to a third party or agency. The lease will restrict them to extracting the minerals within a certain amount of time.
This is a good way to sell mineral rights as you could make more money in the future if the land turns out to be particularly rich in certain minerals. The next leasing period could be worth more than the initial one, though there is the chance that nothing is found in that time and the price of mineral rights on your land drops dramatically after the first lease period is up. Again, professional advice is the way forward as this will help you avoid as many of the pitfalls as possible and in the long run will protect both parties for all future dealings and interactions.