How to read drill results and intercepts

Almost every junior mining announcement leads with a line like this one, taken from the illustrative section on the home page:

LX-03: 42.0 m at 2.31 g/t gold, including 6.0 m at 9.80 g/t

This is an invented example, not a real project. It is useful because every piece of the line can be unpacked.

The anatomy of an intercept

• LX-03 is the hole ID. Holes are normally numbered by project, year and sequence, so the ID tells you roughly when and in what order a hole was drilled.
• 42.0 m is the length of core along the hole that crossed mineralization. It is a length measured along the drill path, not the thickness of the mineralized zone.
• 2.31 g/t is the average grade over that length: grams of gold per tonne of rock. One troy ounce is 31.1035 grams, so 2.31 g/t is about 0.07 ounces per tonne.
• including 6.0 m at 9.80 g/t is a higher-grade section inside the 42 m. It is not additional material. The remaining 36 m average about 1.06 g/t.

A quick check shows how the numbers fit together. Multiplying length by grade gives gram-metres: 42.0 × 2.31 is about 97. The high-grade section accounts for 6.0 × 9.80, or about 59 of those 97 gram-metres. More than half of the headline's metal sits in one-seventh of its length.

Units you will meet

Companies sometimes combine several metals into a single "equivalent" grade, such as gold equivalent. That depends on assumed prices and recoveries, so ask for the assumptions before comparing two projects.

Length is not thickness

Holes rarely cross a zone at a right angle. If a zone dips steeply and the hole is drilled at a shallow angle to it, the core length overstates the real thickness. The corrected figure is the true width.

For a simple case, true width is the core length multiplied by the sine of the angle between the hole and the zone:

A good announcement states the estimated true width, or says it is not yet known. If it never does, treat the headline length as an upper bound.

What the cut-off grade does

To report an intercept, a company decides the lowest grade that counts as mineralized. This is the cut-off grade. A low cut-off gives a longer, lower-grade intercept. A higher cut-off gives a shorter, richer one. The same hole could be reported as 42.0 m at 2.31 g/t or as a much shorter section at a higher grade.

Neither is wrong. They answer different questions. Ask which cut-off was used, and whether the company applies the same rule to every hole it reports.

Questions to ask about any drill result

1. Where is the hole, and how does it relate to the rest of the drilling? A single spectacular hole says less than a pattern of holes.
2. What is the estimated true width?
3. Which cut-off grade was used, and was a top cut or cap applied to extreme assays?
4. Who took and analysed the samples, and what quality controls were used?
5. Are the weaker or empty holes reported with the same prominence as the strong ones?

An empty hole is not a failure of reporting. Hole LX-05 in the illustrative section tested a different target and found nothing significant. A company that shows its misses alongside its hits is giving you a more complete picture.

What a single result cannot tell you

One intercept is an observation about a thin line through the ground. It does not by itself establish how much material there is, whether it can be mined or what it would cost to process. Those questions are answered later, through resource estimates and economic studies. See the stage guide for where drill results sit in that sequence.

This is educational material. It is not investment advice, and the example is invented.