Like many catchy mining phrases, "Drill to Mill," "Pit to Plant," "Mine to Mill" and "Mine to Market" are deceptively simple descriptions for complex, multi-layered processes. In the mining cycle, drill and blast (D&B) is arguably the first and most important step to get right.

Without a holistic approach built on integrated solutions, it can also be the hardest and most costly.

D&B impacts the entire mining process, from mining equipment efficiency, through crushing and grinding circuit performance, to recoveries and final product quality. Costs and energy usage increase throughout the comminution process. Efforts targeted at optimising the blasting process can pay huge dividends downstream, reducing costs and energy consumption.

A correct blast not only optimises the cost of that blast, it improves the total cost profile of the entire mine. Correct fragmentation means easier digging, reduced shovel cycle times, reduced rework, less oversize causing downtime at the crusher, lower cost crushing, and improved tons per hour (TPH) through the processing plant. 

Improved dilution tracking elevates this by ensuring the right material is sent to the plant versus the waste dump or waste being processed for no economic gain. Not only does this improve ore recovery, it impacts processing plants downstream where vital blending can be required to ensure the plant operates efficiently.

Add high-accuracy machine-guidance drills and shovels with state-of-the-art positioning capabilities, and you wield a profoundly profitable trifecta; yield, fragmentation, and dilution.

This trinity improves a mine's entire cost profile: reduced blasting costs, reduced rework, improved diggability, increased ore recovery, less crushing, higher TPH through the plant, and improved efficiency for ore processing.

But how does a mine harness and harmonize the technology necessary to accomplish all of this?

Blast design

A holistic approach to the drill and blast process starts with a well-designed blast pattern, effectively executed using high-precision drills; it includes proven fragmentation analysis and blast monitoring solutions that minimise loss and dilution and delivers the data necessary for the next blast pattern design; and it ensures a continuous D&B feedback loop underpinned by technology that not only increases profit from every blast, but also increases a mine's purchasing power over one of the most expensive part of the process - explosives.

The D&B workflow begins with details of the mine plan and ore control for each mining bench, to engineer the blast design. Blast holes are drilled, then loaded with explosives and stemming, and then the material is blasted. It sounds straightforward, but blast optimisation is anything but. A multitude of activities must be tracked, and numerous pieces of information must be connected. 

Hexagon solutions facilitate each step, beginning with the design of the blast. Some mines still depend on 2D, 3D, or AutoCAD for basic blast design, with no means to compare actual versus plan, and no standardisation of the process.

If there is no blast-hole database, you cannot store data about the type or length of blast, or who designed the pattern.

Hexagon's mine planning portfolio features HxGN MinePlan Blast, a comprehensive software utility for D&B and reconciliation. Rather than risking high-wall stability problems, uneven blasting, poor fragmentation, unnecessarily high energy costs, and dangerous working conditions, MinePlan Blast incorporates charge and blast design templates that are based on sound engineering principles and methods proven in mines worldwide.

The solution incorporates geology and other properties from the block model into the workflow. Blast designs can quickly be created to improve fragmentation, reduce energy costs, and offer management greater insight via configurable reporting and drill operator scorecards. Drillhole scorecards ensure improved transparency and insight into D&B progress.

High-precision drilling

Hexagon's MineOperate portfolio features machine guidance for drills (as well as dozers and loading equipment). The OP Pro HP solution ensures that drilling is performed to the right position and elevation. It provides accuracy and instantaneous feedback, meaning improved loading times across the fleet, less misrouted material, fewer hours of rework on ramps, roads, and benches, and fewer over- and under-drilled holes. It is proven to improve both the quality of material produced and fragmentation with precise drill hole placement and depth.

OP Pro HP integrates with Hexagon's operational management hub, MineEnterprise, meaning a single source of reporting and support.

Blast movement monitoring

Preparing for the D&B stage, mine operations have already spent significant amounts of money (running into the millions) to accurately locate the ore body and maximise the information known about the surrounding geology.

 

The ability to accurately track blast movement is a huge benefit for mines striving to be smarter and more sustainable. It is a highly variable process that can cost mines millions of dollars in lost revenue per year from ore loss - where valuable ore is sent to the waste pile, dilution - where waste is sent to the mill, and misclassification - material containing a specific grade of ore is sent to the wrong downstream location.

Blast Movement Technology (BMT) is an integral part of Hexagon's D&B solutions, providing accurate ore location information for open pit mines. Via sensors and software, BMT provides accurate blast information that is used to recover all a mine's resources. It ensures that post-blast, the mine retains a full vision of where its ore body moved to.

The solution collects data from blast movement sensors, which move with the blasted material. Software is used to transform the data into actionable insights - from the post-blast location of ore to the outputs of more precise dig lines based on the measured movement.

The ore movement is monitored by using the patented blast-proof BMM (Blast Movement Monitors) sensors that measure the 3D movement of the ore body. Using BMT technology, a large Canadian copper mine saved more than US$70,000 in one blast. The amount is calculated from the additional ore recovered minus the copper that would have been recovered from dilution if the ore blocks were mined in situ.

The D&B solution suite links the knowledge of the ore block from the exploration phase, through to the mine planning phase. This connects the blast planning and execution phases to make decisions about the mine's ore recovery, ore loss and dilution and fragmentation, which can heavily impact the downstream operation and ore yield.

Through continued focus on research and development, the BMM system can potentially be incorporated into other digitisation plans. On the hardware front, this has materialised in the FED, a semi-autonomous UAV fitted with a BMM detector that can access the muck pile and locate the BMM sensors post-blast. For software, algorithms now address a soft bulk ore polygon module, where mines experiencing economic challenges based around misclassification can utilize the BMM technology.

BMT's integration into the Hexagon mining portfolio brings a wealth of knowledge about how ore bodies move, adding greater insight into other key considerations that are critical to accurately measure and plan for entire life-of-mine value chain.

Fragmentation analysis and blast optimisation

Measurement of key blast results, such as fragmentation size and ore movement, unlocks opportunities for increased profitability and is key to evaluating the effect of the blast design and the implementation of the blast process. A mine must measure this process in order to manage and improve it - a principle enshrined in Hexagon's approach to D&B.

This approach enables blast scoring and the creation of blast templates based on multiple data sources.

Hexagon's Split Engineering systems are flexible and can monitor in different areas and process along the operation automatically, such as in shovels, excavators, loaders, haul trucks, crushers, conveyor belts, mill feed and screen decks. The entire process can be connected from pit to plant for a unified approach to fragmentation management.

 

Monitoring trends in size at each point in the comminution circuit enables operational adjustments in real-time. Alarms can be created for oversize events, reducing the downtime from inefficiencies caused by blockages and broken screen decks.

The results can be impressive, as the following examples illustrate:

• Modifying the blast design to reduce size from the blast can increase diggability and truck load factors, reducing load and haul costs by eight per cent. Benefits can include 35 per cent decrease in dig time, 10 per cent decrease in truck loading time, 10 per cent increase in truck load and reduced maintenance costs. Typically, load and haul costs represent 20 per cent of total costs. If total mine cost is approximately US$12 per ton then load and haul would be about US$2.40 per ton. If a 40 million tons/year operation decreased load and haul costs by eight per cent, the reduction is US$8 million per year.
• Measuring rock size on screen discharge conveyors can detect oversize from screen panel wear or holes. In some applications, if an oversize particle is detected three times in one minute, the control system shuts the process so the offending hole in a screen panel can be repaired.
• Increasing fines in SAG mill feed can increase throughput from 10 to 20 per cent. For a mine producing 200,000 tons/year copper in concentrates, revenue can increase by more than US$20 million per year.

A uniquely holistic approach

The ability to tailor fragmentation outcomes and to minimise ore loss and dilutions through blast movement monitoring are proving to be highly sought after. This uniquely holistic view of the operation combines key knowledge banks, such as geology behaviour, effects on powder factor, blast design, planning and fleet management.

Further integration will allow real-time communication between solutions, which can minimise costs, time delays and unforeseen anomalies.

Just like OEMs offering fleet management, the explosive supply companies are innovating in a near space. This is strategic for their business, but maybe not the mine's. Explosives are a commodity, and mines buy a lot of them. By offering technology, explosive suppliers are hoping to avoid that commodity pricing challenge they face by differentiating over the whole blast activity. Why let them?

The technology is not the most expensive part of D&B; the bulk commodity explosives are. By standardizing on technology from one of the explosive manufacturers, mines lose purchasing power to get the best rates on the commodity explosive material.

A comprehensive D&B portfolio delivers the power to improve the most vital part of the mine, where everything starts with the drill and blast, without losing purchasing power over the bulk commodity blasting material.

Seven easy steps to monitoring a blast

• Activate the BMM sensors
• Install BMMs in dedicated monitoring holes prior to blasting and record their position
• Blast
• Detect BMMs by walking the muck pile with our detector to locate the position of each BMM sensor
• Combine drill and blast, geology and BMM system data in our software, BMM Explorer
• Proprietary translation defines post-blast polygons
• Excavate new accurate ore location to maximise ore recovery

The result: Ore boundaries are redefined to reflect the measured movement, allowing the production team to dig in the precise location of the ore and waste.

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Hexagon is a global leader in sensor, software and autonomous solutions. Its Mining division solves surface and underground mine challenges with proven technologies for planning, operations and safety