Drilling Exploration Targets

Geophysical surveys serve as a crucial first step in mineral exploration programs. They help exploration geologists identify subsurface anomalies and narrow down large areas to specific targets worth investigating further.

The typical workflow goes:

1. Geophysical surveys detect anomalies that might indicate mineralization - using methods like magnetics (for magnetic minerals), electromagnetics (for conductive ore bodies), gravity (for density contrasts), or induced polarization (for disseminated sulfides)
2. Target generation - interpreting the geophysical data to identify drill targets
3. Intrusive follow-up - drilling to physically sample the anomaly and confirm whether economic mineralization is present

This approach is cost-effective because geophysical methods can cover large areas relatively quickly and cheaply compared to drilling. Drilling is expensive and time-consuming, so you want to be strategic about where you drill. The geophysics helps ensure you're drilling in the most prospective locations rather than testing blindly.

Drill mobilization is one of the major logistical and cost challenges in exploration. Getting a drill rig to remote targets can be a significant undertaking:

Access challenges:

• Building or upgrading roads/trails to reach the target
• Helicopter support for really remote sites (very expensive)
• Seasonal limitations - some areas only accessible when ground is frozen, or conversely, when it's dry enough
• Environmental permitting and minimizing surface disturbance

Rig logistics:

• Heavy equipment needs suitable terrain
• Water supply for drilling (often a major constraint)
• Fuel and supplies
• Crew accommodation in remote locations
• Sample storage and transportation

Cost implications:

• Mobilization/demobilization can sometimes cost as much as the actual drilling
• Weather delays while equipment is on site
• Multiple targets need to be planned efficiently to minimize moves

That's why the exploration sequence matters so much - you want to be confident in your targets before committing to the expense and effort of moving a drill. Sometimes companies will do additional ground-based work (soil sampling, prospecting, geological mapping) after geophysics but before drilling to further refine targets and prioritize which ones justify the drilling costs.