Short-Term Production Scheduling

Short-term production scheduling converts production intentions into dated work at identifiable locations, with assigned resources and material destinations. It connects the extraction plan with the activities needed to deliver it; dispatch and task execution then act on a finer operational timescale. The distinctions depend on the mine's planning structure.^[1]

A useful schedule answers more than how much ore to produce. It identifies which work is ready, which prerequisites remain, what resources can be used together, and how departures from the plan will affect subsequent work. Surface and underground mines share these questions, although their activities and constraints differ.

Define the Scheduling Window and Decisions

Three time concepts need separate definitions. The horizon is the future interval being considered. The resolution is the size of the periods, or the precision of event times, used to place activities. The review frequency determines when the schedule is reconsidered. Calling a plan “short term” does not establish any of these automatically.

The resolution should expose conflicts that matter to the decisions being made. An underground planning model by Campeau and colleagues uses detailed near-term periods and more aggregated later periods. Its treatment illustrates why one level of detail need not cover the whole horizon: immediate assignments require resource detail, while later work may be represented more broadly until information improves.^[2]

The scheduling boundary also needs to be explicit. A plan ending at ore extraction leaves transport and plant delivery to another decision process. A plan covering delivered feed must include those interfaces. Record what the schedule is authorized to change, such as equipment assignments or work order, and what requires a separate design or planning decision. This prevents a local adjustment from silently changing the agreed mining strategy.

Establish the Current State and Material Basis

Start from a dated representation of actual conditions. A previously issued plan describes intentions; unfinished work, changed access or updated material information must be carried into the new schedule. Give partially completed tasks their remaining quantities and remaining prerequisites, rather than restarting them in full or treating them as finished.

The following distinctions provide a practical structure for the scheduling data:

Specify the measurement boundary for each target. Rock broken, ore loaded, material delivered to a stockpile and plant feed are different movements or states of inventory. Adding them together as separate production would count the same material more than once. If stockpile reclaim is included, distinguish it from newly mined feed.

In Blom and colleagues' open-pit scheduling demonstration, the coarse plan assigns material to destinations, while operational scheduling determines how equipment can enact those movements. This distinction matters because an acceptable tonnage and destination plan still requires feasible work locations, movements and equipment assignments. The demonstration treats a particular single-product setting; its models are examples of decision separation, rather than a complete representation of every mine.^[3]

Represent Activities, Resources and Time

Describe a task by its location, measurable completion criterion, required resources and links to other tasks. Define whether it can be interrupted and resumed, and whether changing the assigned resource introduces extra setup. These choices should reflect the work, because arbitrary splitting can create an apparently feasible schedule that cannot be executed.

For compatible cyclic underground work, Åstrand and colleagues represent one complete production cycle at a specified location as a job, and its successive operations as stages. Mobile equipment travels between these stationary jobs, consuming time. One job therefore represents a cycle, rather than all future work at that location. The analogy does not establish a universal sequence for underground methods.^[1]

Separate productive effort from elapsed completion time. A task requiring a given amount of crew work may span a longer interval because of interruptions, crew sharing or waiting. Campeau and colleagues explicitly distinguish crew hours from minimum elapsed task duration. Treating them as interchangeable can place a successor before the predecessor can actually finish.^[2]

Resource calendars should identify scheduled unavailability, task compatibility and any shared limits. Burt and colleagues' operational mine model links loading, shared truck capacity, crusher feed and fixed maintenance events. It allows material movements to be partitioned around maintenance, subject to the model's assumptions. The engineering implication is that available equipment must be checked over the actual work intervals: a fleet total for the whole period does not establish simultaneous capacity. Their study addresses a utilisation subproblem after blending decisions, so its results do not establish feasibility of an unrestricted mine-wide schedule.^[4]

For review, ask who or what performs each concurrent task. If the same crew, machine or exclusive workplace appears twice, resolve the conflict explicitly. State how travel, setup, productive work and planned stoppages enter durations; otherwise the same delay may be omitted or counted twice.

Build Feasible Alternatives and Set Priorities

Begin with the approved physical and engineering constraints, then test alternative assignments and timing. A production objective cannot authorize access to an unreleased area or override a design restriction. Distinguish those limits from preferences, such as a target sequence that can be changed after checking its consequences.

Objectives also differ by horizon. Nehring and colleagues' conceptual sublevel-stoping model combines a short-term grade-deviation objective with medium-term economic scheduling. It includes development, production drilling, backfill and equipment restrictions. Its useful lesson is the need to reconcile near-term assignments with the larger production plan; it does not prescribe those objectives for every deposit or operating contract.^[5]

When comparing feasible candidates, document the priority order. A candidate that delivers more immediate tonnes may delay enabling work, use a scarce blending source or create a less favourable starting position for the next window. Compare the resulting unfinished work and remaining ready areas as well as current output. This is an engineering decision about consequences, not simply a ranking of equipment utilisation.

A schedule should report unmet targets openly. If no candidate satisfies the current commitments, identify the binding restriction and the decision needed to change it. Relabelling a target as achieved, or moving unfinished work beyond the displayed horizon, conceals the conflict instead of resolving it.

Release, Review and Revise the Work

The GMG's 2019 underground short interval control guideline connects shift scheduling with in-shift and post-shift reviews. It calls for current task and resource status, communication of assignments, assessment of emerging delays and checks on whether previous corrective actions worked. It also distinguishes the original baseline from revised targets: current actions can change while the baseline remains available for performance comparison. The guideline's workflow provides a way to connect scheduling with feedback; review intervals and information systems still need to suit the operation.^[6]

Maintain a clear distinction between the issued commitment, actual completion and the latest forecast. Each serves a different question: what was agreed, what happened, and what is now expected. A revised schedule should identify affected tasks and interfaces so that one crew does not follow a superseded assignment while another follows the replacement.

Before releasing replacement work, confirm its own prerequisites. Being an alternative in the scheduling model does not demonstrate readiness in the mine. Conversely, recording a delay should preserve useful detail about its cause: unavailable equipment, incomplete enabling work and changed conditions call for different decisions.

Test Changes and Feed Results Back into Planning

Consider a qualitative scenario in which a prepared ore source becomes unavailable. A scheduler may find another source that can meet the immediate quantity target. The comparison must then ask whether its destination is appropriate, whether the required equipment can reach it, and whether using it now leaves a later blending or access problem. If the alternative requires unfinished enabling work, its material cannot simply be substituted into the current period. This reasoning exposes linked decisions without assuming a particular mine layout or production rate.

Evaluate outcomes at the same locations and measurement boundaries used in the schedule. Aggregate tonnage alone cannot show whether essential preparation was completed. Compare planned and actual completion, remaining work and the assumptions behind durations. Repeated discrepancies warrant a change to the planning basis; isolated disruptions may only require a local revision. Where the short-term plan repeatedly cannot implement the longer plan, return the conflict to that planning level with the relevant evidence and alternatives.