In the second episode of our new series on drilling grades we...

In the second episode of our new series on drilling grades we look at two more of 2022’s key base metals, Mr Copper and Mrs Zinc.

Let’s dig in.

Two fundamental factors to keep in mind when reading a company’s drilling results are:

1. What is an average grade across the sector?
2. What is the price context of the metal?

Unlike precious metals, base metal grades are expressed in terms of percentages (%) instead of grams per tonne (g/t).

But there’s more to consider than just grades when assessing the viability of a project.

Grades versus scale and prices

In global zinc mining, grades of 2.5-3% are considered medium grade and the price is approximately A$4731 per tonne.

Tickled zinc

Zinc has also found a home – nay, a mansion – in renewable energy infrastructure as a handy weapon vs. corrosion – and its value soared more than 50% in 2021.

Then there’s the anxiety around a greater concentration of global zinc production emanating out of China, the metal recently added to the US Geological Survey’s list of Critical Minerals.

The Biden Administration’s efforts to reduce its reliance on Chinese-produced zinc have boosted Western-based projects such as Ironbark Zinc’s (ASX:IBG) Citronen zinc-lead project.

And now for some geometry

The geometry of the ore body is another very important factor that can have an impact on the cost of extraction, according to Ironbark Zinc Managing Director Michael Jardine.

“If the ore body is in a ‘pillow-like’ cross-section that lends itself easily to open pit mining, it will be much cheaper to extract than an ore body that is pivoted on the diagonal,” he says.

How the ore body lies will also affect the waste to ore ratio, with a horizontal ore body involving less waste than a diagonal one of equal grade.

Diagrams of a project’s ore body are often included in announcements and presentations.

urisdiction: something gotten in the state of Denmark

Jardine says this is an extremely important factor to consider while evaluating exploration results.

As miners develop and operate projects on a multi-decade basis, they benefit from stable government, tax and permit regimes, as well as the ability to easily move funds in and out of a country.

He says that while Greenland, where Ironbark Zinc is developing Citronen, is a relatively ‘new frontier’ for mining, it benefits from the stability it derives from being part of the Kingdom of Denmark.

“There are opportunities there today that would have been extracted decades ago if they were in WA,” he said.