Gold and copper producer Doray Minerals has unearthed extremely high grades of gold and copper at its Deflector mine in Western Australia.

The company (ASX:DRM) told investors that grade control drilling had exposed a lode that hosts “bonanza” grades of as high as 299 grams per tonne (g/t) gold and 10.5 per cent copper.

The news sent shares up nearly 5 per cent to an intra-day high of 32.5c on Thursday morning.

Grades above 5g/t gold and 1.5 per cent copper are generally considered high grade.

Miners often use the term “bonanza” to describe grades that are well above what is considered high grade.

Grade control drilling is a key part of the mining process and it gives miners necessary information about depth, slope and alignments.

It helps a company determine the economic limits of a mine.

Doray Minerals (ASX:DRM) shares over the past year.
Doray Minerals (ASX:DRM) shares over the past year.

These high grades were discovered at depths ranging between 14m and 121m down hole.

Doray said the lode, which is known as the “Link Lode”, is continuous along a strike length of about 250m and 300m down dip.

Managing Director Mr Leigh Junk said the Da Vinci, Link and Contact 3 Lodes are significant discoveries in the short time that Doray has been mining underground at Deflector.

“We’re confident that we’re looking for other parallel ones of these,” Mr Junk told Stockhead. “Our orebody is now over a kilometre long.”

While Doray has previously uncovered high grades of over 100g/t, Mr Junk said it is probably the “most consistent high-grade lode” the company has found so far.

The high grades could potentially extend the life of the Deflector mine and it will definitely increase production.

“We haven’t fully discovered how big it is so we don’t know whether it affects the mine life or whether we can mine it during the current life, but it really upscales the operation given that it is higher grade and it adds more quality and more robustness to the whole operation,” Mr Junk said.

Doray plans to include the latest results in its upcoming annual resource and reserve statement, due for release in the first quarter of the 2019 financial year.