Stages of Mineral Exploration

The stages of mineral exploration move from finding targets, to sampling and drilling, to defining a resource, and then to economic studies and development.

This page explains each stage in plain words and uses the Basin Gulch project of Lannister Mining as a worked example. Basin Gulch already has more than 320 historical drill holes, so its current focus is resource definition: work aimed at a maiden mineral resource estimate.

Last updated: November 2026

What are the stages of mineral exploration?

Most projects follow six broad stages. Names vary between companies and countries, and projects can work on more than one stage at once, but the order is broadly the same. The right column shows where Basin Gulch stands at each stage, based on facts reported by Lannister Mining.

Stages of mineral exploration, with the Basin Gulch project (Lannister Mining) as the example
Stage	Typical work	Basin Gulch status
1. Target generation	Study regional geology, historical records and earlier mining activity to pick areas worth testing.	Done historically. Basin Gulch sits in the historic Philipsburg Mining District.
2. Early exploration	Map rock types and collect soil, rock and trench samples to outline mineralized zones.	Trenching reported gold and silver over lengths up to 159 meters.
3. Discovery drilling	Drill the best targets to see whether mineralization continues below surface.	Done historically, with mineralization intersected from surface.
4. Resource definition	Drill systematically, confirm older data, and prepare a first resource estimate.	Current focus: more than 320 historical holes plus planned confirmation and expansion drilling.
5. Economic studies	Assess whether a deposit could be mined profitably through staged engineering studies.	Not started. Follows a resource estimate.
6. Permitting and development	Obtain permits, finance and build a mine.	Not started.

Which stage is Basin Gulch at?

Resource definition, with room to explore

Basin Gulch is at the resource definition stage for its historically drilled zone. Lannister Mining plans confirmation and expansion drilling of historical drill intercepts and new work programs toward a maiden mineral resource estimate.

At the same time, about two-thirds of the property is unexplored, so other target areas are still at the earlier stages of exploration.

Why historical work shortens the path

Starting from more than 320 historical drill holes means much of the target generation and discovery drilling has already happened. The work ahead focuses on confirming and extending known mineralization rather than searching from scratch. See the Basin Gulch historical drilling for the data.

Is mineral exploration risky?

Yes. Mineral exploration is high risk: most exploration projects never become mines, and results can change as drilling proceeds. A large historical data set reduces some uncertainty but does not remove the need for confirmation drilling, resource estimation and economic studies.

For broader background on how mineral deposits are studied in the United States, the USGS Mineral Resources Program and the Montana Bureau of Mines and Geology are useful public sources. Return to the Basin Gulch project overview for the project itself.

Questions about the stages of mineral exploration

What are the stages of mineral exploration?: The stages of mineral exploration usually run from target generation, to mapping and sampling, to discovery drilling, to resource definition, then to economic studies and development. Basin Gulch already has extensive historical drilling and is working toward resource definition with its planned maiden mineral resource estimate.
What does a gold exploration company do?: A gold exploration company searches for and defines gold deposits that could one day become mines. Its work includes mapping, sampling, trenching, drilling and resource estimation. Lannister Mining is a gold exploration company focused on Basin Gulch in Montana, where it plans more exploration toward a maiden resource.
What is the difference between mineral exploration and mining?: Exploration finds and measures a deposit; mining extracts it. Exploration companies drill, sample and estimate resources, while mining companies build and operate mines. Basin Gulch is at the exploration stage: Lannister Mining is working toward a maiden resource estimate and is not producing gold.
Is mineral exploration risky?: Yes. Mineral exploration is high risk because most exploration projects never become mines, and results can change as drilling proceeds. Historical data such as the 320+ drill holes at Basin Gulch narrow some uncertainty, but confirmation drilling, resource estimation and studies are still needed. Read company disclosures carefully.
What is a maiden mineral resource estimate?: A maiden mineral resource estimate is the first formal estimate of the tonnes and grade of mineralization on a property, prepared under a reporting standard. For Basin Gulch, Lannister Mining plans to use historical drilling and new work programs to produce its first resource estimate.
What comes after a maiden resource estimate?: After a first resource estimate, exploration companies typically keep drilling to grow and upgrade the resource, then move toward economic studies. Lannister Mining describes its plan as further exploration and development toward a maiden resource; its investor presentation is the place to check stated plans beyond that milestone.

See all 44 questions in the Basin Gulch FAQ