The previous sections outlined how to plan an operation that includes GEGrade Engineering but stemmingGravel used to pack the top of blast holes to confine explosive energy. from these sections are one of the challenges, which is equipment productivity impacting labour productivity and therefore operational productivity.
Historically, when higher production rates were required, more capital i.e. more equipment and was deemed the appropriate solution. Lately, industry is more inclined towards the use of technology for mine productivityMetrics representing overall perfomance of an operation. improvements with some mixed results albeit some technologies are still in its infancy.
The first steps in ensuring that the GEGrade Engineering targets can be met is to look at the operational challenges and identify which mining activities are most affected by changes in mine productivityMetrics representing overall perfomance of an operation. . The first step in mine planning is obviously the orebody and therefore the mining faceActive area of shovel/truck loading operations. /benchIndividual levels within an open pit. or the stoping envelopes. The following are therefore deemed the front-line production activities impacting overall mine productivityMetrics representing overall perfomance of an operation. :
Historically, when higher production rates were required, more capital i.e. more equipment and was deemed the appropriate solution. Lately, industry is more inclined towards the use of technology for mine productivityMetrics representing overall perfomance of an operation. improvements with some mixed results albeit some technologies are still in its infancy.
The first steps in ensuring that the GEGrade Engineering targets can be met is to look at the operational challenges and identify which mining activities are most affected by changes in mine productivityMetrics representing overall perfomance of an operation. . The first step in mine planning is obviously the orebody and therefore the mining faceActive area of shovel/truck loading operations. /benchIndividual levels within an open pit. or the stoping envelopes. The following are therefore deemed the front-line production activities impacting overall mine productivityMetrics representing overall perfomance of an operation. :
- Developing the ore reserveRemaining extractable elements within the ultimate pit.s. That is either stripping of wasteMaterial determined to be below a predetermined grade or economic threshold. rock (open pit) or the establishment of access mine development (underground) to gain entry or access to the orebody.
- The next step is to break the orebody (drilling and blasting)
- Following the fragmenting of the rock is the loading of the rock
- The final big step (set of activities) is to get the mineralised rock from the mining faceActive area of shovel/truck loading operations. to the processing plant
The development of the ore reserveRemaining extractable elements within the ultimate pit. also entails these activities and it is essential to also consider what development would be required and the additional development orwasteMaterial determined to be below a predetermined grade or economic threshold. stripping required when following a GE mine plan. Finding solutions to these challenges requires the simulation of mining equipment movements and modelling the equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination. impacts associated with the GE mine plan. The front-line mining equipment simulations are:
- drill rig requirements
- Loading tool/unit and impacts on the loading unit cycle timeTime taken for a single truck to go from shovel/dig face to destination.s and non-productive times
- truck fleet and impact on truck cycle timeTime taken for a single truck to go from shovel/dig face to destination.s
- Impacts of the GE mine plan on alternate rock movement systems such as IPCC, conveyors or Railveyor and to test these potential impacts.
In open pit mines the equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…).s are generally matched to the ore movement requirements, predicated on the processing plant targets. Once the best or appropriate shovels/excavators/loaders are selected to meet the total rock loading specifications and rates, the matching truck or conveyance system is then selected. When developing GEGrade Engineering and non-GE mine plans it is generally found that GE mine plans need to schedule more total rock and involve higher productivities or production rates in ore and low-grade mining faceActive area of shovel/truck loading operations.s. In underground mines GEGrade Engineering techniques might impact the actual stoping method which impacts equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). selection and unit sizes.
The challenge is therefore understanding the size of the most appropriate equipment units/models and the number of units, but more importantly scheduling the appropriate productivity parameters for the different equipment units, particularly based on the GEGrade Engineering operational activities and rock destinations.
With GE mine planning, fast and reliable data is essential and to achieve the modelled GEGrade Engineering benefits it is conceivable that there would be a need for additional technical services activities. One example will be face sampling, additional infill drilling and mapping or grade scanning. Not only do these additional data collection services impact equipment productivities but GEGrade Engineering activities might also introduce additional rock destinations which invariably impacts how low grade or even sub-grade rock is now been mined and transported. The GE mine plan therefore not only rejects wasteMaterial determined to be below a predetermined grade or economic threshold. rock but GEGrade Engineering material might now report to an additional destination and then there is the oversizeMaterial above a specific size (generally used to define material that is retained on a screen deck). and undersizeMaterial below an specified size (generally used to define material that falls through a screen deck). or rejected and accepted ore streams as a result of the GEGrade Engineering infrastructure requiring handling, hauling and tipping.
The next step of GE mine planning, post equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). simulations (which includes the modelling and understanding of the mine productivityMetrics representing overall perfomance of an operation. factors) comes equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). optimisation. This is an important yet underrated planning step, particularly when planning new projects or reasonably new operations which might utilise contractors during the initial production periods. equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). optimisations are often more constrained for existing fully operating mines as the equipment unit sizes might already be selected and delivered to these operations. For these projects or operations, fleet optimisation then looks to optimise the GE mine plans by possibly re-locating the GEGrade Engineering pre-processing activities or introducing additional technologies to minimise impacts on equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination.s. Recent studies have shown that mine production improvements are rarely solved by simply adding more equipment units and mostly focus on the identification of operational bottlenecks within the production fleets and activities and to eliminate key impacts through smarter planning or better technologies.
The purpose of this paper is to outline which productivity measures are generally impacted by operational GEGrade Engineering and to outline the methods to deal with these measured and impacts.
The challenge is therefore understanding the size of the most appropriate equipment units/models and the number of units, but more importantly scheduling the appropriate productivity parameters for the different equipment units, particularly based on the GEGrade Engineering operational activities and rock destinations.
With GE mine planning, fast and reliable data is essential and to achieve the modelled GEGrade Engineering benefits it is conceivable that there would be a need for additional technical services activities. One example will be face sampling, additional infill drilling and mapping or grade scanning. Not only do these additional data collection services impact equipment productivities but GEGrade Engineering activities might also introduce additional rock destinations which invariably impacts how low grade or even sub-grade rock is now been mined and transported. The GE mine plan therefore not only rejects wasteMaterial determined to be below a predetermined grade or economic threshold. rock but GEGrade Engineering material might now report to an additional destination and then there is the oversizeMaterial above a specific size (generally used to define material that is retained on a screen deck). and undersizeMaterial below an specified size (generally used to define material that falls through a screen deck). or rejected and accepted ore streams as a result of the GEGrade Engineering infrastructure requiring handling, hauling and tipping.
The next step of GE mine planning, post equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). simulations (which includes the modelling and understanding of the mine productivityMetrics representing overall perfomance of an operation. factors) comes equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). optimisation. This is an important yet underrated planning step, particularly when planning new projects or reasonably new operations which might utilise contractors during the initial production periods. equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). optimisations are often more constrained for existing fully operating mines as the equipment unit sizes might already be selected and delivered to these operations. For these projects or operations, fleet optimisation then looks to optimise the GE mine plans by possibly re-locating the GEGrade Engineering pre-processing activities or introducing additional technologies to minimise impacts on equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination.s. Recent studies have shown that mine production improvements are rarely solved by simply adding more equipment units and mostly focus on the identification of operational bottlenecks within the production fleets and activities and to eliminate key impacts through smarter planning or better technologies.
The purpose of this paper is to outline which productivity measures are generally impacted by operational GEGrade Engineering and to outline the methods to deal with these measured and impacts.
Mine Productivity Factors
General impacts on Mine Productivity factors
The factors impacting mine productivityMetrics representing overall perfomance of an operation. are mostly synonymous for both open pit and underground mining operations and these are:
- Data turn around and detailed destination block models
- Sound and productive mine planning
- Processes, procedures and supervision ensuring the operations follow the mine plans always
- Safe and productive mining areas and setup (uneven pit floors, poor decline ramp floor conditions, poor “housekeeping” excessive water/mud unsafe mining faceActive area of shovel/truck loading operations.s and in underground mines, good ventilation)
- Optimised loading areas limiting excessive equipment movements and relocation
- Drill plan and number of blast holeCylindrical hole used to load explosives into unbroken material.s per domainGeological, statistical or spatial groupings used for modelling. or rock destination
- drill rig penetration rates and non-operating times (movement of drill rigs)
- loader/shove/excavator loading rates achieved
- rock fragmentationGeneral term for broken rock (e.g. muckpile, crusher product etc..). profiles and rock muck placement
- Loading unit setup (optimising loading unit swing angles and interface with trucks or conveyance systems
- Sound equipment maintenance planning and ensuring the equipment mechanical availability is maximised
- Optimised loader/truck interface
- Minimising equipment sighting and positioning times
- Limiting equipment passing and queuing to improve the equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination.s (wide roads, enough passing bays underground etc.)
- Optimised haul routes
- Limiting or eliminating truck speed impacts/nodes within the haul route which slows down the truck and requires the truck to accelerate with a full load again whilst on an inclined ramp/road
- Weather conditions and the mine plan/design layout enabling the best or optimal management of weather impacts
Equipment Selection impacts
The following points summarise the impacts productivity factors and activities may have on equipment and therefore equipment selection:
- Modelling and analysing more data and developing grade controlStage at which final boundaries between ore and waste are calculated. and Grade Engineering operational block models. These models require a significant amount of data frequently updated and getting these updated models ready for improved geological-and mine planning targets often negatively impact decisions and then operations. Depending on the Technical services, especially ore control processes the protocols and Quality Assurance procedures may inhibit the flexibility of operational plans which ultimately impact activity sequences and then equipment utilisation (productivity).
- Drill and blasting planning and blasted stocks (ensuring sufficient blasted faces are available enabling sufficient direct ore feedMaterial entering a predetermined system. , GEGrade Engineering destination feedMaterial entering a predetermined system. and wasteMaterial determined to be below a predetermined grade or economic threshold. rock) in a complicated mine planning environment could have impacts on drill and blast patterns, the number of blast holeCylindrical hole used to load explosives into unbroken material.s and location where drills need to work and therefore drill rig movements. The more equipment (particularly drill rigs) need to move/relocate it increases the equipment’s non-productive time and diminishes equipment productivity. Drill-and blasted stock should (insofar possible) not create the operational bottlenecks which is the key reason for contingency drilling capacity, this could mean that some drill rigs might be operating at lower productivities (excess drill rigs available) and these impacts need to be simulated and accounted for during GE mine planning.
- With GE operationsSites which have implemented Grade Engineering strategies. there will likely be direct ore feedMaterial entering a predetermined system. (higher grade ore blocksBlocks exceeding economic or grade thresholds. where GEGrade Engineering activities might not prove beneficial) and these blocks of ore will be directly loaded and transported to the primary crusher, but then there will be likely be low and medium grade ore blocksBlocks exceeding economic or grade thresholds. and in many cases sub-grade blocks (ore just below marginal economic [https://wikiore.com.au/tiki-index.php?page=Scheduling and Cut-Off Optimisation&structure=GE Resource&page_ref_id=83| cut-off]) which require unique drilling and blasting patternsDifferent blast configurations used within different domains. and certainly require specific GEGrade Engineering rock destinations, whether it is to a crusher and screening facility or a combination of crushers, screens and ore sorting units. These additional rock destinations generally impact the number of mining faceActive area of shovel/truck loading operations.s i.e. mining stopes (underground) or mining benchIndividual levels within an open pit.es (open pit) that needs to be ready, developed, prepared, drilled and blasted and available for loading. If there is significant grade variability within the mining areas, the movement or interim relocation of the loading units could potentially increase (distances travelled or moved without loading or frequency of movement/relocation) when compared to a conventional grade-driven mining operation. These additional non-productive hours are what impacts mine productivityMetrics representing overall perfomance of an operation. with a GE mine plan. These directly impact the loader productivities and could either justify additional loaders or might justify a slightly larger loading unit. Some mining operations which may now require one more loading unit could possibly justify going to smaller sized loading fleet and adding one smaller loader (as opposed to simply adding another larger loader and this loader being underutilised). Smaller loading units better utilised might be more cost-effective compared to larger loaders underutilised challenging popular believes that the bigger the equipment the more cost-effective the mining operations. It is therefore obvious how important fleet planning and equipment simulations are as part of GE mine planning.
- Once the loading unit sizes and number of loading units have been modelled and identified and the location of these loading units scheduled on a month and even weekly basis, the appropriate or optimal truck size matched to the loading units follow. It is conceivable that a mining operation might have mixed equipment fleetAvailable equipment at a given operation (e.g. trucks, shovels, water trucks etc…). sizes (different size loading units with their matching truck fleets operating in different areas of the mine or performing different mining tasks). The matching of trucks to the loading units are vital and generally looks for a 4-to 6 bucket pass truck fill factor and not half buckets (if it can be helped). Large shovels generally look to have a full 3-pass loading to fill a truck as partial bucket loading is a definite no in truck/shovel matching. The loading cycles impacts the time the truck spends waiting to be filled and even impact subsequent truck queuing. The most commons truck cycle timeTime taken for a single truck to go from shovel/dig face to destination. impacts are with truck queuing, sighting and positioning near the loading unit and then the loading time until the truck pulls away on its journey to the rock destinations. The same goes for LHD units loading trucks underground, but LHD’s usually increase their loading performances by making use of underground rock stockpiles and to limit the one-way distance the LHD unit must transport rock. Optimising haul routes and simulating the specific nodes within the haul routes and planning/scheduling the trucks with realistic cycle timeTime taken for a single truck to go from shovel/dig face to destination.s are key to planning GE operationsSites which have implemented Grade Engineering strategies. .
- When alternate technologies are considered, particularly with rock tramming/hauling and where minor improvements on truck cycle timeTime taken for a single truck to go from shovel/dig face to destination.s could lead to reasonable reductions in truck fleet numbers, it is prudent to consider these technologies during mine planning. Technologies which are proven to optimise equipment movements and cycles and therefore equipment productivities include:
- Equipment tracking and dispatchSystems for allocation of equipment plans (eg. Trucks, shovels etc…). systems
- Trolley Assist lines for larger open pit trucks (improving fully loaded uphill speeds of trucks)
- Auto collision devices on trucks improving sighting, spotting and truck positioning at the loaders
- Autonomous systems (still new) seems to improve drilling cycle timeTime taken for a single truck to go from shovel/dig face to destination.s and truck cycle timeTime taken for a single truck to go from shovel/dig face to destination.s. The added benefit with autonomous systems is that fully autonomous mines could reduce labour and operators significantly and these autonomous systems always enable the optimal performance of the equipment (maximising acceleration, gear shifting, breaking and positioning activities)
GE Infrastructure impacts on Mine Productivity
The other key aspect impacting equipment and therefore mine productivityMetrics representing overall perfomance of an operation. is the rock destinations but more so the layout, position and interface of the GEGrade Engineering infrastructure with the mining equipment, and largely either the loading units (if positioned in the pit, near the mining faceActive area of shovel/truck loading operations.s) or the trucks if located on surface outside of the mine.
The following figures depict the typical GEGrade Engineering infrastructure and potential impacts on the mining equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination.s and therefore mining equipment productivity:
The following figures depict the typical GEGrade Engineering infrastructure and potential impacts on the mining equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination.s and therefore mining equipment productivity:
Figure 4-1: Standard Mining Operation (no GE)
Figure 4-3: GE infrastructure on the mining face
Several GE mine planning studies concluded that the average cycle timeTime taken for a single truck to go from shovel/dig face to destination. of equipment are impacted negatively, and these potential impacts are largely attributed to specific GEGrade Engineering infrastructure and equipment interfaces. There are studies which concluded that GEGrade Engineering infrastructure, when appropriately positioned or located, could improve equipment cycle timeTime taken for a single truck to go from shovel/dig face to destination.s. This observation or finding seemed to be significant where large shovels interface with a crusher/conveyance unit ultimately feedMaterial entering a predetermined system.ing the trucks. The shovel productivities can be optimised, and the trucks could reduce their spotting times significantly with a “drive-through” layout where the truck is filled by some feedMaterial entering a predetermined system.er unit. The simulations for these types of solutions indicated that some rock surge capacity is required ultimately enabling the shovel to keep loading even in the event of a truck shortage. These types of loading/crushing and conveying systems furthermore enable the implementation of scanning and sorting technologies to be considered which allows direct feedMaterial entering a predetermined system. and GEGrade Engineering ore to be diverted to specific locations or truck loading positions.