Each company has been assigned to a category / description based on its dominant focus. Note that some of the companies are involved in more than one category.

Producers:
These are companies that have at least one mine in production. The producers have active exploration and/or development projects that provide upside potential of a magnitude that can drive the share price independent of moves in the metal prices.

Feasibility Study or Pre-Feasibility Study:
This category encompasses companies that have a defined deposit and that are already moving toward the start of commercial production. In some cases they already have processing facilities and other infrastructure in place. Even though the companies have a defined deposit, there is still considerable risk in developing a mine. That risk is offset by the potential for large gains as the companies advance their projects toward the start of production.

Defined Resource:
The earliest stage of defining a metal deposit – known as an inferred resource – attracts a low valuation. As a deposit moves through the exploration and development cycle, and the uncertainty is lessened, the value can be expected to increase. Not all deposits will be successfully advanced. The value of a company can rise substantially as its deposit is successfully advanced toward production.

Outlining a Resource:
These companies have identified potentially economic mineralization through surface sampling (for example, trenching), widely spaced drilling and perhaps some underground tunnels. Companies in this classification are those for which there is a reasonable expectation that the next phase of drilling will produce sufficient information on which to estimate a resource. Companies in this category still carry a risk, in that the value depends on getting favourable drill results. That risk is mitigated by existing evidence for the presence of mineralization of a size and concentration that are potentially economic. The value of the company can be expected to increase substantially if the company is successful at defining a resource.

Prospect Generators:
These are companies with considerable geological talent that acquire interests in numerous early stage exploration properties, often by simply staking open ground. By focusing on a particular region, they can develop a leading edge of geological understanding that allows them to see opportunities before others and inexpensively accumulate numerous prospects. Prospect generators typically use joint venture partners to help fund their exploration programs. Bringing a partner into a project to fund the high risk early stages of the exploration program is generally preferable to giving away part of the company by way of an equity financing. If managed well, the prospect generators should have a continual flow of projects that should  eventually result in a significant discovery and a big gain in value.

Exploration Companies:
These are companies that have one or more early stage exploration projects. The companies in this category intend to fund the work on the projects themselves. They take on the exploration risk and in return, they  retain their interest in the projects. While this approach is highly speculative, they exceptional management and geological teams and have high-quality projects. Ideally the projects have already had the benefit of at least some prior work. The high level of risk of these companies is offset by the potential for big payoffs from exploration success.