Webinar Recording: “Determining and Justifying the Optimal Pushback Number. Economic Effect”

Hello everyone, welcome to our first webinar of 2025! I’m Anya, responsible for business development at K-MINE. Before we get started, don’t forget to follow our LinkedIn page for updates on our latest news and upcoming webinars. Thank you for joining us today!

In today’s webinar on Determining and Justifying the Optimal Pushback Number: Economic Impact, we’ll explore how to calculate the best pushback strategies and their financial implications.

Later, we’ll be joined by Dr. Bright Afum, an expert in mine planning and design, who will share his insights and expertise on effective pushback strategies.

Let me first introduce K-MINE. Founded in 1994 in Ukraine, we have now expanded across Europe, the U.S., and Canada. Our team consists of geologists, engineers, and developers, many of whom are certified in NI 43-101 and JORC reporting standards. We serve clients ranging from small exploration teams to large corporations, always focusing on high-quality and cost-effective solutions.

Our software is specifically designed for the mining industry and supports every stage of a mining project, from initial exploration to full-scale production. With 12 versatile modules, our software caters to both open-pit and underground mining environments.

What makes our solution unique is its adaptability. Whether you’re running a small operation or a large corporation, you can choose the modules that fit your specific needs—whether it’s just one module or the entire suite. Our modules cover geological data management, surveying, and optimized mining plans, while also offering integration with IoT devices and dispatch systems for real-time monitoring.

Our solution is built on real-world industry experience and is designed to address challenges encountered in our consultancy work. Our team includes Qualified Persons who prepare reports in compliance with NI 43-101, SK-1300, and JORC standards for different project stages like PFS, FS, DFS, MRE, and PEA. We have extensive expertise across various hard rock commodities, including critical minerals. If you’re interested in how our services can benefit your project, feel free to leave a comment or reach out through our website.

Now, let’s dive into today’s discussion. We’ll start with the fundamentals: what pushbacks are, their purpose, how to implement them, and the rules that guide their construction. From there, we’ll explore the economic impact of the number of pushbacks. Since we’re software developers, we’ll also demonstrate how pushbacks are managed within our software, exploring different scenarios and automated design options, which are crucial for planning. We’ll touch on scheduling, analyze outcomes, and discuss whether pushbacks are necessary, their optimal configurations, and other important considerations.

Let’s begin by explaining what pushbacks are and their purpose. Many in mine planning are already familiar with them, but in today’s dynamic raw materials market, detailed planning is more crucial than ever. Strategic planning sets the stage for long-term company decisions, with mining operations being one of the largest expenses for any mining company. A well-detailed mine development plan until the deposit’s depletion is essential, and this is where pushbacks play a key role.

Pushbacks allow for managing mining intensity across different areas, coordinating operations over time. A pushback represents a controlled phase of pit development, consisting of unique, adjacent volumes that can be mined with current equipment while maintaining practical geometric limits. Typically, pushbacks are mined sequentially; once one’s overburden is removed, equipment shifts to begin stripping another area, ensuring efficient mineral extraction.

If you’re wondering why pushbacks matter or how they differ from traditional methods, let’s compare. Conventional mining involves progressive pit development without a clear mining front, leading to multiple zones influenced by specific conditions. With pushbacks, cuts are made progressively downward to a set width until reaching the maximum feasible depth, providing better control over operations.

Conventional mining allows access to multiple mining faces simultaneously, making it easier to blend materials to meet processing plant requirements. It’s adaptable to changing conditions, but it comes with a higher stripping ratio and increased haulage distances, which can significantly raise operational costs. On the other hand, pushbacks lower costs, improve equipment productivity, and provide better planning predictability, ultimately enhancing profitability and attracting investors.

Anya (00:00):
And now joining us, a mining consultant and a professor at the University of Mines and Technology in Ghana, and also an assistant professor at Queen’s University in Canada, Dr. Bright Afum. Bright, nice to see you, and we’re happy you found the time to join us.

Dr. Bright Afum (00:19):
Yes, thank you very much. Nice to see you again, Anya.

Anya (00:25):
So, talking about pushbacks and how effective they are, what do you think about them in your personal work? What do you consider the key elements of effective pushback?

Dr. Bright Afum (00:43):
All right, in talking about pushback, I think we should also mention cutback. Pushback and cutback are actually different, but we use them interchangeably.

The pushback refers to expanding the pit by incorporating more areas outside the pit while maintaining existing parameters such as berm height and width. Cutback, on the other hand, allows for changes in these parameters, hence the term “cutback.” If we are maintaining parameters, it is a pushback; if we change them, it should be referred to as a cutback.

Pushback itself is a very important element in mine planning, and the key elements to consider for effective pushback creation include balancing technical, economic, environmental, and operational factors.

Firstly, geotechnical stability must be assessed to determine whether slope angles need to be maintained or varied, and if geological changes impact berm and bench configurations.

Secondly, economic optimization is critical. We must ensure that the pushback is profitable and maximizes net present value (NPV) rather than merely extending the life of the mine for social or governmental reasons.

Another key consideration is the grade requirement for the processing plant. The incoming reserves must meet the plant’s requirements to optimize production efficiency.

Finally, equipment and operational constraints play a major role. The available space and mining width may require adjustments in equipment size or layout to ensure efficiency.

Anya (06:28):
And you mentioned pushbacks and cutbacks. How do you decide which one to use?

Dr. Bright Afum (06:38):
If the existing mine parameters remain unchanged, we employ a pushback. However, if parameters such as slope angles and berm widths need adjustment, then it becomes a cutback. The decision largely depends on factors such as geological stability, operational feasibility, and economic considerations.

Anya (07:45):
What are the most common mistakes made in pushback planning?

Dr. Bright Afum (07:57):
One of the biggest mistakes in pushback planning is focusing only on short-term profitability while neglecting long-term mine goals. Many planners fail to integrate future phases or operational bottlenecks into the design.

Another common issue is overlooking geological uncertainty. Engineers often assume ore continuity, leading to surprises during excavation. Collaboration with geologists and processing teams is crucial to avoid such errors.

Additionally, many fail to account for commodity market fluctuations. It’s important to incorporate dynamic market trends to optimize long-term economic returns rather than relying on static models.

Anya (12:00):
Any innovations in pushback creation that are worth noting?

Dr. Bright Afum (12:58):
Yes, incorporating real-time data and market trends into pushback planning is crucial. Many mining companies fail to adjust their strategies based on future commodity price trends, which can lead to missed opportunities.

Another innovation is leveraging artificial intelligence and machine learning to predict geological variability and optimize planning. AI can help identify trends and provide better insights into pushback configurations.

Anya (15:05):
If you had to define your personal criteria for an optimal pushback, what would they be?

Dr. Bright Afum (15:31):
An optimal pushback should start with modeling based on geological and economic factors, followed by adjustments using professional experience. Modeling provides a strong foundation, but real-world expertise is essential to fine-tune the results.

Key criteria include understanding rock strength, assessing changes in geological formations due to historical blasting, and ensuring the pushback boundary captures the full value of the ore while maintaining safety.

Anya (18:30):
Do you prefer automated or manual pushback creation?

Dr. Bright Afum (18:39):
I prefer a hybrid approach—starting with automated pushback generation to define boundaries and then using manual adjustments to fine-tune constraints. Automation provides consistency and speed, while manual refinement ensures practical feasibility and flexibility.

Anya (20:35):
Are there alternatives to the pushback approach in strategic planning?

Dr. Bright Afum (20:41):
Yes, alternatives include creating satellite pits around the main pit or transitioning to underground mining methods when depth limitations arise. Additionally, robotics and automation can be used to optimize operations within confined spaces.

Anya (23:53):
Any final tips or interesting cases you can share about strategic planning?

Dr. Bright Afum (24:02):
One key strategy is planning for resource depletion by considering future commodity prices and stockpiling ore that may not be profitable today but could be valuable in the future.

Another important factor is the use of AI and machine learning to improve strategic planning by predicting geological trends and optimizing ore recovery.

Mining companies should also focus on continuous auditing and cross-functional collaboration from the early stages of mine planning to avoid costly mistakes later.

Anya (32:16):
All right, well, thank you so much, Bright. Thank you for your insights.

Dr. Bright Afum (32:20):
Thank you very much. I’m glad to have contributed to the discussion.

Anya (32:27):
Thank you.

When planning pushbacks, several important rules must be followed. Each pushback must consist of unique, connected blocks to facilitate road planning and maintain safe pit slopes. Pushbacks should also align with the available mining equipment and contain enough minerals of the right quality to keep the processing plant running efficiently. These factors play a crucial role in determining the overall feasibility and economic viability of a mining operation.

Pushbacks have evolved over time, with their origins dating back to the early days of large-scale mining operations. Initially, they were introduced to optimize space utilization and reduce costs in large open-pit mines. Over the decades, advancements in technology have enhanced pushback design, making it a widely adopted practice by major mining companies such as Rio Tinto and BHP.

Now, let’s take a look at real-world examples of pushback strategies in action. One of the earliest large-scale applications was at the Morenci copper mine in Arizona, where pushbacks helped optimize operations and reduce costs. Today, companies like Rio Tinto and BHP continue to refine their pushback strategies, leveraging advanced software to achieve greater efficiency and economic returns.

Once you’ve decided to implement pushbacks, key questions arise—how many pushbacks are needed? What should their width and depth be? How can we optimize stripping ratios to ensure profitability? These are the questions that drive effective pushback planning, and our software provides the necessary tools to answer them.

In the next section, we’ll demonstrate how pushbacks can be created using K-MINE software, both automatically and manually, to ensure optimal results.

To wrap up, strategic pushback planning is critical to the success of any mining operation. Our software helps you make data-driven decisions, ensuring efficiency and profitability. If you have any questions or need further assistance, feel free to reach out.

Thank you all for joining us today, and we look forward to seeing you at our next webinar.