RECONCILIATION & GRADE CONTROL    

We found that most of these decisions were bad because certain pieces of available information had been ignored, discounted or given insufficient attention…Kepner, C H & Trego, B, B (1981)  

By becoming more effective and efficient an organisation can achieve its business objectives without the wholesale destruction of the company’s more important asset… Eckes, G (2001)

It is an indisputable fact that the mineralisation in the ground, the basis of every mining operation, is a non-renewable resource. Once the mineralisation is mined, it is gone. The trouble is how do we know if we are being effective and efficient in our mining practices? The nature, location and extent of our economic mineralisation is known from sparse data; we are making decisions (e.g. ore vs. waste) on the basis of incomplete knowledge simply because the cost of acquiring complete knowledge is prohibitive (from both a financial and a time perspective).

What to do? There are two distinctly related approaches to decision making under uncertainty that are routinely applied in the mining industry; grade control and reconciliation.

Grade Control

If we have a well functioning grade control system, our knowledge of the rock properties should improve as we get closer to the physical act of mining. As we progress through a project more and more data becomes available. We can use that data to improve our understanding of what is economic to mine. Similarly as we get closer to production the uncertainty associated with external factors such as metal price, production rate, mining costs and metallurgical performance reduce.

So… With all this increasing data we should be able to make better ore/waste allocation decisions – right? That’s where grade control comes into play. The grade control process is the last chance to make a correct allocation of ore and waste and therefore it is imperative that the process is as robust and fit for purpose as possible. Errors, and low precision at the grade control stage can create extreme challenges to business performance.

The impact of grade control doesn’t stop with just the ore/waste allocation issue. QG has investigated many grade control and production issues and can help you delve deeper into the consequences of your grade control, resource estimation and mine planning systems to understand the consequences of decision making with different levels of data and understanding.

Reconciliation

There are a lot of myths and misconceptions about reconciliation. In recent years we at QG have noted an increased focus on reconciliation performance across the industry. Understandably so, monitoring your reconciliation performance is the only measure you have of how well your resource and reserve estimates are performing. Unfortunately this increased focus has not helped dispel the misconceptions around reconciliation or resolve many of the issues involved with getting high quality, meaningful and business critical knowledge from the reconciliation process.

At QG we believe reconciliation is not just about software. Sure you need good information management systems and practices but by itself software won’t help you understand what is happening or help you make the right decisions. There is a real risk of drowning in data and not making valid conclusions. Consequently many operations waste incredible amounts of time trying to fix reconciliation ‘problems’ and not addressing the real issue.

QG’s reconciliation expertise ranges from developing the complete process to reviewing or auditing existing systems. We also have substantial experience in problem solving using your data and reconciliation practices.

To make sense of your reconciliation performance you need expertise in:

•         Sampling
•         Quality management
•         Data management
•         Resource modelling and estimation
•         Geostatistics
•         Statistical process control
•         Mining operations and system
•         Equipment capabilities
•         Drill and blast
•         Load and haul
•         Stockpile management
•         Survey
•         Crushing, grinding
•         Metallurgical processes (e.g. leaching, flotation)
•         Marketing
•         Management

Or… essentially the entire value chain from in-the-ground to sold-product.

No matter how simple or complex your operation, from single mines feeding single processing plants through to multiple mines, multiple plants and multiple products, QG can help formulate the mess and find the issues you need to focus on to improve your business performance.