In this episode of Fresh Thinking, Dr Tarrant Elkington Snowden Optiro's General Manager, speaks with Dr Leon Lorenzen about the critical role of metallurgical and processing due diligence in mining projects. They explore how process plants are evaluated, why throughput is often a hidden risk, and the challenges of forecasting performance in both operating and new mines. Whether you're reviewing an acquisition or building a new operation, this discussion provides valuable insight into identifying red flags and understanding the real-world complexity behind the numbers.

This podcast at a glance:

00:20 – What due diligence really means in a processing context

01:30 – Using the process design baseline to evaluate plant performance

03:00 – Why high recoveries can be misleading without throughput context

04:50 – Common red flags: when ounces look good, but costs and feed rates don't

07:00 – The importance of test work and geological input in forecasting

09:30 – Case study: transition from open pit to underground and its impact on throughput

10:00 – Unique risks with new mines and the ramp-up phase

13:00 – Why expertise and independent evaluation are essential for sound investment decisions

If you would like to contact Tarrant and Leon: contact@snowdenoptiro.com

🔔 Subscribe for more Fresh Thinking about the mining industry.

This video podcast is also available as a free video podcast on Snowden Optiro's YouTube channel.

Snowden Optiro is a resources consulting and advisory group that provides independent advice, consulting and training to mining and exploration companies, their advisors and investors.

We help mine developers to advance their projects, mining companies to improve their operations and their professionals, and investors to de-risk their investments by the provision of quality advice, training and software in the field of Mineral Resources and Mineral/Ore Reserves.

Find out more about Snowden Optiro: https://snowdenoptiro.com
Professional Development Training: https://snowdenoptiro.com/professional-development/

In this Fresh Thinking episode, we’re discussing one of mining’s toughest technical challenges: refractory gold ores.

Dr Tarrant Elkington, Snowden Optiro General Manager sits down with metallurgical expert Dr Leon Lorenzen to explore why some gold refuses to come quietly, and the high-stakes processing paths needed to recover it. From pressure oxidation to bioleaching and ultrafine grinding, this episode uncovers the costs, complexities, and future of refractory ore treatment.

If you're a geologist, metallurgist, or investor—this one's essential listening.

This podcast at a glance:

00:00 – Welcome & Introduction

00:45 – What is refractory gold? And why is it a problem?

02:30 – The role of geology and early detection

04:00 – How refractory ore impacts project economics

05:15 – Overview of processing methods: POX, BIOX, Albion, roasting

07:30 – How to choose the right processing path

09:00 – Real-world examples of refractory gold plants

11:00 – The future: centralised hubs and economic scale

12:30 – Final thoughts and advice for developers and investors

If you'd like to connect with Tarrant and Leon: contact@snowdenoptiro.com

This video podcast is also available as a video podcast on our Snowden Optiro YouTube channel: https://www.youtube.com/@SnowdenOptiro

🔔 Subscribe for more Fresh Thinking about the mining industry.

Snowden Optiro is a resources consulting and advisory group that provides independent advice, consulting and training to mining and exploration companies, their advisors and investors.

We help mine developers to advance their projects, mining companies to improve their operations and their professionals, and investors to de-risk their investments by the provision of quality advice, training and software in the field of Mineral Resources and Mineral/Ore Reserves.

Find out more at: https://snowdenoptiro.com/

Professional Development courses: https://snowdenoptiro.com/professional-development/

#mineralprocessing #SnowdenOptiro #FreshThinking #gold #podcast

In Episode 106 of Fresh Thinking by Snowden Optiro, Executive Consultants Ian Glacken and Graeme Lyall discuss the practical realities of mineral resource classification.

This episode explores current best practices and highlights the importance of combining data-driven methods with geological insight. Whether you're a junior or major, this conversation will help sharpen your classification strategy and confidence levels.

This podcast at a glance:

⏱️ 00:15 – Why resource classification matters across global reporting codes

⏱️ 01:55 – Introduction to the 90-15 approach for confidence-based classification

⏱️ 04:00 – The dangers of the “spotted dog” effect and how to avoid it

⏱️ 05:21 – Calculating drill spacing the smart way: distance-to-holes technique

⏱️ 07:04 – Alternatives to drill spacing: kriging variance and its limitations

⏱️ 08:00 – Why close spacing doesn’t always mean high confidence

⏱️ 09:01 – The two-indicator approach: origins, application, and benefits

⏱️ 13:01 – Assumptions, limitations, and when to adjust the 90-15 rule

⏱️ 17:00 – When the two-indicator method doesn’t fit: deposit-style considerations

⏱️ 18:00 – What’s coming in Part 2: simulation and scorecard approaches

If you would like to contact Ian and Graeme: contact@snowdenoptiro.com

🔔 Subscribe for more Fresh Thinking about the mining industry.

This podcast is also available as a cideo on our Snowden Optiro YouTube channel: https://youtu.be/7CqcvRDi9Jw

Snowden Optiro is a resources consulting and advisory group that provides independent advice, consulting and training to mining and exploration companies, their advisors and investors.

We help mine developers to advance their projects, mining companies to improve their operations and their professionals, and investors to de-risk their investments by the provision of quality advice, training and software in the field of Mineral Resources and Mineral/Ore Reserves.

Find out more at https://snowdenoptiro.com

Professional Development courses: https://snowdenoptiro.com/professional-development/

contact@snowdenoptiro.com