Gold mining companies have several challenges in operating their mines. The value of the gold mining company reflects its mineral resources and its ability to extract, process and recover the gold and get it to the market in a sustainable way. Often deposits are low in grade (between 1 to 4 grams per ton on an average across the Life of Mine) and occur in veins in fractured rock. External dilution further lowers the grade,which impacts the recovery. For low-grade deposits, more ore must be mined to extract the same value as a high-grade deposit. The mine to mill interface and grade control process are particularly important to operations and need a special focus. The mineral processing circuit, on the other hand, needs to be tuned to process variations of softer oxide deposits vs. harder sulfide deposits to ensure predictable recovery. Recovery also happens in multiple material streams – typically one via a gravity circuit for heavier particles and finer particle via CIL/CIP (Carbon in Leach or Carbon in Pulp). The recovery calculation needs to measure and calculate the value using a weighted average grade methodology. Metal accounting is an important process to understand and minimize the Gold in Circuit and to ensure accurate measurements and data management to ensure a recovery of all the gold.
Role of data to optimize Gold Operations
Data is a key enabler for digital transformation. Mining is data rich with many modern equipments, and processes all creating multiple data points in real-time. In a gold operation, understanding the grade, throughput, recovery and asset effectiveness need to be put into perspective in various time horizons. Data is essential for operational teams to make informed decisions about the operation. Examples include achieving faster truck turnaround times, lowering open pit unit cost through managing mean time between failures(MTBF) and higher mining rate(TPOH), monitoring optimization of pit wall slope angles to maximize dumps, improve dilution control for improved head grade, fragmentation efficiency for increased plant milling rate and optimised metallurgical process inputs for increased gold recoveries.
The right data is not always available for managers and supervisors to make decisions. Data is stored somewhere in a source system but is often not available when it is needed. Managers and supervisors don’t always have time to search, analyze and combine the data. The context of the data needs to be understood and presented to managers and supervisors to support the right decisions being made. The visibility on what was happening and where it was happening needs to be heightened, for a more informative view of the business. For example, a load and haul supervisor may look at lower Trucks Ton Per Operating Hour versus high Utilization to review the number of trucks deployed; a mill supervisor may notice consistent high crushed tons but lower Gold ounces produced to review dilution; or a drill & blast supervisor may look at high penetration rates in addition to high re-drill percentage to review the drill pattern. Supervisors and managers need to have the right data and information and be able to trust it to make the right decisions to benefit the operation.
Digital Platforms and Technologies
The management system of choice for many managers is Microsoft Excel. Excel allows their own version of what is important to them and plug the required numbers into their model to get an understanding of what they should do. While this data is largely provided to the immediate users of the systems, much of the data is locked up in specialized / legacy systems. The data is not amenable to collaboration and results in islands of data and reporting. A holistic picture that combines the data to support the strategic initiatives needs to be presented as intuitive visualizations. Fortunately, data platforms in the cloud can serve data needs that are both real-time and aggregated showing from short-term shift KPIs to long-term yearly trends. These platforms can consume operational data sets and supplement with third-party data sets (such as fatigue etc.) to complete the picture. Cloud gateways can connect mining data sources and collect and process data for intuitive KPI visualization and the combined effects as represented below, can power the Gold miner to a much higher level of productivity.