QA/QC in Mining: safety, reliability, and best practices in the mineral sector

Some consequences of the Brexit affair:

• Fall of the world stock exchanges on which the shares of mining and exploration companies were traded;
• A drastic reduction in mineral exploration around the world;
• Revision of the Mining Codes;
• Preparation of new regulations and best practice recommendations;

 

After this, in order to obtain quality and confidence in the data generated, the mining industry began to be guided by norms and procedures defined by international standards, such as the Mining Code. JORC,CRIRSCO as well as the new CBRR in Brazil.

The establishment of standards for reporting resources and reserves, drilling data, chemical analyses and geological models, as well as the need for these activities to be validated by competent, qualified and certified professionals in international geoscientific communities, is a requirement aimed at preventing new frauds from occurring.

The strategy for obtaining the necessary data for quality assurance and control is known as QAQC and must take into account multidisciplinary contributions that include statistics, geostatistics, geology and the theory of sampling (TOS), which are fundamental for establishing precision and accuracy targets.

Shall we talk a little more about this?

 

In today's text we'll cover:

• What is QA/QC?
• What is the purpose of QA/QC?
• What are the areas of application of QA/QC in mining?

 

QA/QC defines programmes and procedures that meet quality standards in order to identify and, above all, CORRECT errors in a process. However, there are still some misunderstandings between these two terms. So let's understand each of them and then realise their importance in mining.

• Quality Assurance Control (QA). A set of pre-established activities necessary to ensure that a given activity or operation reaches an acceptable level of quality;
• Quality Control (QC). A set of operational techniques and activities used to determine the level of quality actually achieved in an operation;

The QA/QC function in mining is related to the procedures, techniques and tools for sampling work, databases, laboratory tests and any studies related to the exploration of mineral resources and mineral prospecting, ensuring quality control and security of this information.

These processes must be understood and applied in ALL phases of mineral exploration and are not limited to the insertion of control tools (blanks, standards and duplicates for chemical analyses). They must be created according to the criteria and needs of each mineral deposit, and it is not feasible for other companies' projects to use procedures that have already been created.

The aim of QA/QC is to guarantee the reliability of the data generated from the start of the project right through to the mining and operations phase, ensuring that data such as ore content and the quantity of mineral reserves are reliable.

The application of QA/QC procedures should take place throughout the mineral survey. It is important to emphasise that only by controlling and guaranteeing quality is it possible to meet the demands of the consumer market by supplying highly reliable products and services.

The use of sophisticated quality control methods can only be justified if the data on which they are based is precise, accurate and reliable. The results are generated based on the reliability of these estimates.

This, then, is the importance of QA as a tool that acts from the start of the project to prevent mistakes from being made, and QC as an active, statistical process that aims to correct, improve processes and take corrective action.

QA/QC can be applied at various stages in mineral exploration and exploitation:

A very important phase in a mineral project, chemical analysis is responsible for determining the ore content found in a research or mining area. For this reason, a reliable and transparent result of the analytes is essential. Some control tools are inserted into the sampling process or used during physical preparation and chemical analyses, each with its own function within the chain.

QA can be applied to the definition of standards, blanks, duplicates and replicates to be used throughout the sampling, preparation and analysis process.

QC can be used to generate graphs and reports to monitor the performance of these processes.

Some controls applied are: Mass control (controls the starting mass versus the final mass of the process, helps to identify changed or lost samples), preparation blank (assesses possible contamination due to poor cleaning of equipment), duplicates (measure of precision), reference materials (standards, measure of accuracy, sample with known reference content), check assay (measure reproducibility, analysis carried out in a secondary laboratory.

The database is the repository of information on the mineral deposit. If the information it contains is incorrect, all the steps already taken, as well as future work, could be jeopardised. It is therefore expected that all data will be properly validated, guaranteeing decision-making.

It is highly recommended that an administrator be appointed to manage the database information and that different permissions be assigned to each type of user, so that data manipulation is completely traceable and auditable.

QA can be applied to define the format for entering information, the routines and scripts for validating the information, and also which professionals will be responsible for entering it.

QC can be applied to define how often this information will be backed up.

The use of incorrect information such as drill hole coordinates and underestimated or overestimated grades can jeopardise the progress of the mineral project.

The geological model is a three-dimensional representation of the mineral deposit, based on sampling data (boreholes, channels, trenches, etc.), density and ore content found in a given study area.

QA can be applied when defining what information will be used to create the model.

QC can be applied when carrying out reconciliation (comparison between model estimates and realised production).

Thus, a good QA/QC programme is one that is active and reviewed throughout data collection, allowing corrective action to be taken quickly.

In this sense, projects that apply good practices are prepared and organised for internal or external audits. In this way, they improve team productivity, reduce costs with unnecessary rework and make the enterprise more attractive to investors.

Therefore, monitoring the main process indicators through a quality assurance (QA/QC) programme must be constant so that there is effective and continuous improvement of the process, preventing the same mistakes from being repeated in the future.

That's why you can count on DMT to implement quality control procedures in your project. We work with different types of deposits, offering quality services at any level of study. Click here to find out more!

• CSA Global.
• Geoscan.
• SRK.
• Igeological.
• IB Mineração.
• Mining Institute.
• Mining Technician.
• GeoAnsata QAQC Course Material.
• QAQC Course Material Instituto Minere.