CHALLENGES IN MINE PLANNING AND SCHEDULING – DISCUSSION
Mining companies today are under increasing pressure to boost output from their existing mines and to bring new projects online quickly. Fundamental to the long-term performance of an operation is geologic modelling and mine planning. To maximize mine profitability, planners and schedulers must create mine plans that match the field as accurately as possible. Not surprisingly, this can be a difficult task, and getting it wrong can result in large unforeseen costs and significant lost revenue opportunities.
Geologists and mining engineers must account for a staggering array of variables – geological samples and data from the mine, the production capacity of available equipment, machinery and manpower availability, customer demand and commodity prices, product cost assumptions and the health and safety of workers. Traditionally, the time and resources required to continually collect this data meant that no one could keep pace with the reality of what’s happening at the mine site. Furthermore, the process of developing mine plans may utilize disparate systems, which introduces inefficiencies in the process and more opportunity for error.
Few challenges in mine planning are discussed in the following paragraphs – by employing efficient system / software the shortcoming can be encountered and the planning system can be upgraded.
A. CAPTURING THE TRUE COMPLEXITY OF MINERAL DEPOSITS THAT MATCHES THE FIELD CONDITION:
Geological models generated for initial feasibility studies are often not detailed enough to provide an accurate picture of a mine suitable for creating detailed production plans – and the software used to develop models in a feasibility study may not be suitable for the production environment. Geological models built for feasibility studies can be oversimplified on complex coal and metalliferous ore deposits, particularly when it comes to modelling faults. As a result, coal / mineral production forecasted in mining plans may not be there when operations uncover the area, making it difficult to predict and plan production. To address the variation between planned and actual production, mining organizations need to balance creating a mine model that matches the field as accurately as possible with the available time to stay ahead of operations.
Software/ module used for geological modelling should be capable to integrate with the geological database to streamline the modelling process. It should be able deal with complex geology and visualisation tools should be able to verify and communicate quickly and efficiently such geological complexity, ensuring accurate results.
Illustrating this complexity, a coal miner was typically modelling and mining two coal intervals but exploration drilling revealed an area with eight coal units and the added complexity of a sand channel unit which presented significant ground control risk. Due to this complexity, the area was mined around. As a result of using an efficient software / module, the miner was able to model the geologically complex area, develop multiple mining scenarios and the coal reserves are now part of the mining plan, increasing the available reserves and the life of the mine.
B. UPDATING MINE PLANS WITH NEW DATA FROM THE FIELD:
Mine planning and scheduling has traditionally been such a time-consuming, labour-intensive process that it prohibits the timely generation of new or updated plans as quickly as new data is received. This is compounded by staff turnover and a shortage of skilled mine planners and geologists to execute planning.
An efficient software / module should be able to accelerate the process of geological modelling, mine planning, and mine scheduling by automating and streamlining processes, and should be able to update the plan continually based on changing conditions in the ground or with workforce, plant, or equipment availability. Engineers then have access to the latest and most accurate information from which to develop mining plans. By integrating planning tools with geological modelling, instant access to geological surfaces and intervals for developing mine designs can be obtained.
C. GENERATING ACCURATE PRODUCTION AND BUDGET FORECASTS:
Managing natural variations in an ore body is extremely difficult, often leading to educated guesses and “fudge” factors based on past experience. Process inefficiencies and technology deficiencies delay or prohibit the inclusion of the latest mine data into the geological models and mine plans in time to stay ahead of operations. Mining plans should incorporate the latest available information to increase accuracy in the geological modelling which provides the foundation and assumptions for mine planning. Accurate geological modelling provides for accurate mine planning and scheduling. Accurate mine planning and scheduling reduces planned versus actual production variances, which increases production predictability.
By continually updating plans based on new field data, guesswork can be eliminated. Efficient software system should be able to automate and streamline the processes and also should enable multiple mine plan scenarios to run to select the most optimal plan. Improving the accuracy of production forecasts eliminate surprises, instil confidence that mining plans would be achieved and sales targets could be met and results in greater budget accuracy. Mine plans which can be executed to meet sales targets within the designed budget will ensure that the designed profit is also achieved.
D. CAPITALIZING ON QUICK CHANGING MARKET AND OPERATIONAL CONDITIONS:
Because of the length of time required to perform some of the geological modelling and mine planning tasks, planning frequency may not be keeping pace with the frequency of change. Mine plans and schedules are difficult to adapt to the changing conditions of a company’s resources, such as its people, plant, or equipment. Geologists and engineering staff focus on the mechanics of developing a mine plan rather than operational improvements. As a result, processes tend to be less automated.
Automation and self documenting tools / features should be available with the efficient software system which should facilitate repeatable and auditable mine planning processes.
Additional benefit of the above automation tool in software is less time is spent by technical staff, geologists and engineers in developing a plan, leaving more time available to examine ways to make the operation more efficient, such as optimizing exploration drilling programs, increasing mine reserves by uncovering ways to mine in difficult geological conditions, and applying the skills of geologists and engineers into ensuring efficient execution of the final plans with field operations. This system ultimately improves the overall efficiency of the mine planning process.
E. STREAMLINING THE FLOW OF INFORMATION BETWEEN THE GEOLOGICAL MODELLING, MINE PLANNING AND MINE SCHEDULING PROCESSES:
If mine planning and scheduling is not run from a single integrated system, geological, mine planning and scheduling data must be moved and re-entered, increasing the likelihood of introducing errors and decreasing mine planning turnaround time. By adopting suitable integrated system, reductions of 40-60% in time spent updating long range mine plans may take place.