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Theory of Sampling Key to Effective Processing Plants

Francis Pitard - Francis Pitard Sampling Consultants


Alejandro Ehrenberg By Alejandro Ehrenberg | Journalist and Industry Analyst - Fri, 08/14/2020 - 09:10

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Q: Why is it important that people in the mining industry be familiar with the Theory of Sampling?

A: The economic impact can be massive if sampling is not done correctly from the very beginning of the process. At the very least, you need to have a foundation on the basics of the Theory of Sampling: what to look for, what can go wrong, how badly it can go wrong. That must be clear in the minds of management when they make important decisions, such as what sampling equipment to purchase. If you look at the world market of sampling equipment, a large majority of the available equipment will not do the job properly. Again, the origin of the problem can be traced back to a deficient knowledge of the Theory of Sampling that is not taught at universities. Most manufacturers do not understand the problem and manufacture machines that are flawed by design. Miners should choose equipment from one of the very few leading manufacturers in the world, including TecProMin. These companies have made the effort to become educated and test their equipment properly before selling it.

A good place to become educated about the Theory of Sampling is my book, which is in the third addition since its publication in 1988. It is written in such a way that the reader can teach himself, with patience and discipline. It can be studied in as little as six months. Of course, teaching courses is also important, as I do at the Colorado School of Mines every year.

Q: Why is knowledge of the Theory of Sampling important during the exploration phase of a project?

A: Achieving a correct sampling practice in a mining project is an iterated process. Analysis is required every step of the way, and the right information must be produced in each stage for the sampling to work. When millions of dollars are spent to explore a deposit, clear protocols implemented by using the appropriate sampling equipment are important so that work can be done correctly from the very beginning.

It is important to educate geologists and have them collect the information that sampling experts need to understand the material’s sampling characteristics. All deposits are different. Geologists drill, then look at the core sample and carry out the logging: they focus on geological information. But they often forget to log what is important for the sampling experts: the size of the particles, where and how they are formed. It is very important that all relevant details are collected from the beginning, so we can start sampling on the right foot.

Q: What was your role in developing top sampling systems with TecProMin?

A: In 2000, with almost 20 years of experience, TecProMin decided to improve its standards. It had Codelco’s backing, because the company was interested in fixing certain sampling issues at their plants.

The main problem started with the design of sampling equipment and sampling methods. There were fundamental flaws there. I led more than 20 courses for Codelco in which TecProMin was always involved. Codelco paid for all the R&D. The trial and error process lasted for three or four years. Today, TecProMin has the best sampling equipment in the world. The success was in great part due to the involvement of a big player like Codelco.

Once upper management was convinced, we were able to quickly change sampling systems in the company’s processing plants, often without the support of the superintendents. It is hard to change habits at that level, but once our sampling methods and better sampling systems were in place, the superintendents came on board. In over a period of 10 years, we had all of Codelco’s operations equipped with proper sampling systems.

But the battle is not over yet. The next step is to develop a companywide care and maintenance culture. It is not enough to have the best sampling systems. There are many things that can go wrong if equipment is not carefully inspected and cleaned every day. You cannot just install an automatic sampling system, clean it once a week, and provide maintenance every six months. It must be a daily, constant practice.

Q: What is the highest international standard for sampling systems?

A: Most international standards on sampling are not good. They are not really standards, but compilations of existing practices from around the world. The fact that a practice is wide-spread does not mean that it is the right one. To address this situation, in 2003, the World Conference on Sampling and Blending (WCSB) was created. It takes place every two years on a different continent. The WCSB brings together the world’s leading experts on sampling. Manufacturers come to the conference and exhibit their products and installations. There is an inspection carried out by a committee of experts, and no system receives our approval unless it is almost flawless. The WCSB standard is the highest in existence today.

Francis Pitard Sampling Consultants provides professional sampling consultation services and educational programs to many of the world's leading companies engaged in such diverse activities as base metals, precious metals, coal mining, steel, aluminum, and base metals smelting, petroleum exploration and production, chemical manufacturing, environmental monitoring and power generation.

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