Mining engineering 

This is the second article of a six-part series exploring the trends and key themes that are shaping the future of the mining industry. In this article, we explore the topic – Mining engineering

Mining engineering is a traditional branch of engineering that deals with the science and art of digging into the earth for useful minerals and rocks. The practical side of mining engineering involves all stages of the resources cycle, from exploration and discovery to mine planning and implementation right through to closure and rehabilitation. As trusted leaders and experts, mining engineers help create safe and productive operating environments. Mining engineering is a crucial part of the process as it encompasses all aspects of the mine and considers the well-being of employees working at the specific site. 

Exploration and discovery 

Exploration and discovery are the roles played by mining geologists. Their role is to delineate ore from waste so that a cost-effective mine plan can be implemented on a mine site. Responsibilities include geologically mapping the ore body, its boundaries and variability, and performing what is known as a mineral inventory of the deposit, or a full picture of the grade and tonnage of the deposit. Mining geologists guide and evaluate the exploration and discovery process. Over the life of a mine, they will also help extend the known boundaries of any additional ore by developing a geological model of the deposit, looking for clues and evidence for additional opportunities for expansion and valuable minerals while always looking for any extra elements and minerals that may make the mine more profitable and viable. 

Mine preplanning 

The mine preplanning phase enables the mining engineer to quickly determine whether a particular mining property warrants further consideration. A properly conducted preplanning phase can come within 10% to 20% of the actual results. This saves the mining engineer valuable time before committing to a fine-tuned analysis. Among the many questions to be answered during mine preplanning are:

• What will the operating conditions for the mine be like?
• How long will it take to complete the project?
• What health, safety, and environmental regulations will affect the project?

To answer these questions, reserve estimation, production and staff planning, and project scheduling are calculated. The impact of regulations can only be assessed by understanding the basic science underlying these considerations. 

Mine planning 

Mine plans are the template for all future productivity and are crucial to success but are only effective if you know how to schedule and execute the plan. The ultimate purpose of mine planning is to devise a strategy that will optimize project economics within the physical constraints of the deposit characteristics. An unreliable mine plan is one that has a short shelf life. It has a short life before it becomes redundant because the plan is wrong and so it needs to be rescheduled. Mine planning is a fundamental part of mining profitability. Firstly, it determines and dictates the quantity and quality of ore that will be produced for sale within the following period. But in addition to that, poor mine planning costs the mine money and therefore reduces profitability. There has been a lot of work on “optimizing” mine plans to produce a plan that shows improved outcomes, such as profit margins or tonnes produced, and we have very good optimization tools available for use now. 

Implementation 

Once the plan is finalized, then it is distributed to a large range of stakeholders, both on-site and off-site (such as the logistics team). The mining company will generally hold one or more planning meetings around that plan and how to ensure it is executed correctly. Invariably most plans become inaccurate relative to the actual mining operation at some time during the life of the plan – often leading to a need to reschedule the operation as it is not possible to use the forecasts from the previous version, or to make decisions based on the old plan. The critical component in a mine schedule is not so much the task themselves, but the interaction between the tasks. Executing the mine plan is all about monitoring and managing interactions between tasks. There is a gap in knowledge about mine planning between planners and executors, while the planners are well versed in why we plan, that is not necessarily the case for executors. 

Closure and rehabilitation 

The science of mine closure and rehabilitation is understood from a legal compliance and liability point of view although this is more of an engineering issue with regulatory oversight. The plan for environmental rehabilitation must be filed and approved before mine closure. Rehabilitation is undertaken progressively, but inevitably the majority is done at the time of closure. Most rehabilitation plans will include a period of monitoring to determine how the local ecology, in particular vegetation, re-establishes post closure. After all, mining is a temporary activity and closing the mine is a great concern for all within the vicinity of the mine. The impact of an abandoned mine on the environment will depend upon the location, climate, commodity mined, the method of mining and how the mine was closed. We can classify the types of impact into physical hazards, emissions and ecology. Most modern mines in most countries are subject to significant environmental legislation and operating conditions. There is a baseline requirement to monitor how the mine will be closed and rehabilitated. 

Conclusions 

Regulation has driven requirements to “as low as reasonably practicable” ALARP, meaning that they require a company to minimize the impact of its operation on the environment. Even in a country such as Australia, which has a very large mining industry, mines occupy around 0.02% of the total landmass. With heavy regulation, government-held financial securities and clear closure and rehabilitation requirements, there is every reason to believe that mines can be developed, operated and closed with minimal impact on the environment. Sustainability should be taken as the sustainability of ecosystems that existed pre-mining and the sustainable use of the land, or much of the land, post-mining.

In the third part of the six-part series, we will discuss mining exploration and geology in Australia.

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