Somewhere right now, a diamond rig sits parked on a pad, engine off. It's supposed to be idle for an hour, tops, while the RC rig finishes the pre-collar so the diamond tail can go in next. That's the plan anyway.

What actually happens is the diamond rig sits there for a full day, sometimes two, burning standby charges while the RC rig runs behind schedule and nobody's tracking it in real time.

That gap costs money, and it starts with a number nobody's watching closely enough: penetration rate. How fast a rig is actually drilling decides how fast the whole schedule should be moving. Most schedules don't move with it.

The schedule everyone has, and almost nobody trusts

Ask around and you'll find most drilling programs, including some of the highest-pressure environments in the industry like underground production, are still scheduled in Excel. People know the limitations. Excel's just easy to set up, and everyone already has access to it.

The real issue shows up the moment something changes on site.

A schedule's only as good as how often it gets updated. The tricky part is that an outdated schedule still looks fine sitting there in the shared drive. It quietly stops being accurate, and people keep making decisions off it anyway.

To keep it live, geologists are typically spending at least a few hours a week and up to half a day a week considering the team chasing updates and making sure everything reconciles. That's real time, time a geologist would rather spend doing geology than maintaining a spreadsheet about it.

Why an outdated schedule is more than an admin problem

Drilling programs run on dependencies. Models need assays. Assays need samples. Samples don't exist until the hole's drilled. When the schedule doesn't reflect what's happening at the rig, everything downstream is planning around a number that's already out of date. The first person to notice is usually a mining engineer waiting on a model that isn't there when they were told it would be.

The RC pre-collar and diamond tail handover shows this well. Where a hole needs RC drilled first and a diamond tail second, the two rigs need tight coordination so one finishes and the other moves straight in. That coordination is usually loose in a static schedule. The diamond rig ends up parked on site, on standby, burning cost while it waits on a job that was supposed to be ready for it.

The stakes look different depending on who you are.

If you're a junior, your schedule is tied to market timing as much as operations. You want your ASX announcements landing when conditions are right and investor attention high. Miss that window because drilling ran behind and you don't just lose a few days. You can lose the moment you were counting on to promote investor interest or raise capital.

If you're running an enterprise program, the pressure sits on a calendar you've already committed to. Say the plan has the mine opening in 2028. Every phase between now and then gets backward-planned from that date. A drilling delay that doesn't get caught early stops being a drilling problem fast. It pushes the opening date out, and that flows straight into cashflow projections you've already banked on.

Different company, same root cause. The schedule didn't catch the change in time.

What actually needs tracking, no matter what tool you use

Whether you're running this in Excel or something purpose-built, the things that matter are the same.

On the rig side, that means real penetration rate against planned rate, and a live view of hole-type sequencing so an RC-then-diamond handover doesn't leave a rig idle on standby.

On the program side, that means downstream capacity like logging and lab turnaround, and an update frequency tight enough that the schedule doesn't diverge from what's happening on site.

Get both right and you're ahead of most programs in the industry, whatever's tracking them.

What CorePlan does differently

Rig Scheduler keeps your drill program forecast aligned with what's actually happening on site. Here's CJ Nieto, a senior database administrator at Coeur Mining, on what that's meant for his team:

"In exploration, the biggest expense by far is drilling, and being able to accurately assess where you are in your drilling program is incredibly important. [CorePlan] also have a rig scheduler where you can put in your drilling program, how much you expect to spend, how many metres or feet you intend to drill, and it'll show you a forecast, how long it's going to go, what percentage you've completed. That's been great."

That same live view now extends further than total metres. It runs down to the individual holes.

Here's what's new:

Schedule and sequence specific holes against rigs. Useful when sequence matters, like RC pre-collars ahead of DD tails or when priorities change.
Day timescale view. Zoom in for short-range planning and rig moves, so you know where rigs should be by the hour.
Hole-level progress. As Plods come in, see what's done and what's still in progress.

Geos and ops managers can now see the key details of their drilling programs in one place, so they have visibility of progress and are able to be proactive in addressing risks and in planning downstream activities

If you want to see what hole-level scheduling looks like against your own program, chat with our team.

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Your rig schedule is only as good as its last update

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