Not everyone easily spots the waste in their disorganization, including mining & quarrying operations, yet it still adds cost & time, impacting your tonnage, output, and profits.
The ability to identify waste enables people to a problem to solve, a starting point to develop them.
Waste: Any activity that consumes resources without creating value for the customer, or Any activity for which the customer is not willing to pay.
All wastes fall into 7 categories (below).
Use this as a checklist draft to help you identify where the wastes are in your quarry or mine and remove them to make your work easier. *draft – looking for more examples of these:
1. OVERPRODUCTION
What is it? Producing what is unnecessary, when it is unnecessary, and in an unnecessary amount; - more, earlier, or faster than is required by the next process or customer.
Quarry / Mine Examples:
Producing products/aggregates which are not required customers
Producing products during a time of the year when they will not be used
Producing more product than there is demand for by customers
Providing copies of reports to people who have not asked for them & will not actually read them
CC’s on emails
Mining capacity surpassing the plant’s ability to process, or making more aggregate than is required by the next process - before it is required/can be processed, or faster than needed (that waits before the next step can process or consume it)
Causes
Misalignment to customer demand. Inaccurate forecasting. Large volume shots. Batching. Equipment breakdowns. Weather (preventing processing). ‘Making the month’ instead of making to demand.
2. TIME ON HAND (WAITING)
What is it? Waste of which the causes originate in waiting from materials, operations, conveyance, inspection, as well as idle time attendant to monitoring and operation procedures.
Quarry / Mine Examples:
Delays when parts haven’t arrived; stock outs; waiting for equipment, parts, tools or supplies
Waiting for a meeting which is starting late
Waiting for upstream operations such as drilling and blasting
Waiting for break downs to be repaired before doing work
Trucks waiting at a dump site, queuing or standing empty;
Operators may sit idle waiting for material or do nothing while their machines are processing
Waiting for information, decisions, clarification of instructions, replies from engineering, management, head office
Excavators waiting for haul trucks to return
Waiting for people or contractors to show up
Anything that stops, slows or hinders production.
Causes
Unclear direction / instruction / manuals. Unlevel workloads or schedules. Supply chain delays. Lack of planning. Lack of preventative maintenance; unplanned maintenance or quality events. Not having the right tools or equipment. Cone liners & wear parts not changed once worn, trying to ‘get a bit more’ out them causing catastrophic failure & downtime.
3. TRANSPORTATION / CONVEYANCE
What is it? Conveyance itself is waste because it creates no value. Created by conveying, transferring, picking up/setting down, piling up, and otherwise moving unnecessary items. Also created by problems concerning conveyance distances, conveyance flow, and conveyance utilization rate. Obviously parts & product must be transported, but any movement beyond absolute minimum is waste. - Any inefficient or avoidable transit/conveyance of material, information, equipment or people.
Quarry / Mine Examples:
Moving processed product from one location to another before it can be further processed
Collecting items from various locations for an assembly/repair (as opposed to having them all kitted one place)
Long travel distance caused by process-oriented layouts
Moving supplies into and out of a storage area
Moving equipment for processing in/out of locations
Moving individual files from one location to another
Moving parts and products unnecessarily
Driving
Hauling material further than necessary
Transporting rock, work-in-process and finished product around the site
Back haul trip of empty trucks
Causes
Poor layout. Using haul trucks instead of conveyors (in most cases). Availability of customer-specific material. Lack of flow planning. Fuel transportation. Crushing too far from blast site. Sub-optimal pile placement.
4. WASTE OF PROCESSING ITSELF (OVER PROCESSING)
What is it? Unnecessary processes and operations traditionally accepted as necessary; & incorrect processing. Actions that add no customer value.
Quarry / Mine Examples:
Extra of anything - multiple screenings of same aggregate, excessive conveyance, etc.
Performing incoming inspections when supplier processes already guarantee defect free products
Continuing to train employees in tasks/skills which are no longer needed
Overwatering roads
Performing steps that have become unnecessary because of design or process changes
Making ‘tidy’ piles
Processing steps that are not technically justified
Hard copies of reports available online
Redundant capture of information (ex. writing by hand, when directly inputting to a word processor follows)
Multiple recordings & logging of same data
Unnecessary data collection
Excessive greasing (can also blow seals or generate friction/heat)
Achieving a tighter specs than the customer requests, can make use of or benefit from; higher grade than customer is willing to pay
Drilling more holes than necessary
Causes
Inefficient equipment/components. Outdated technology. Not maintaining/updating standard operations, training, etc. Narrow focus on specific parts of the operation instead of looking at the entire system. Handing off notes for input instead of direct input. Unclear requirements or specifications.
5. STOCK ON HAND / INVENTORY
What is it? Inventory waste is when anything – materials, parts, assembly part – is retained for any length of time. This includes not only warehouse stock, but also items on site that are retained at or between processes. A buildup of material or information that is not being used; the direct result of overproduction; keeping unnecessary raw materials, parts, WIP & finished goods. Having more than the minimum stock required for a precisely controlled pull system.
Quarry / Mine Examples:
Finished products for which there are no orders
Making more than is required by the next process
Making it earlier or faster than needed; underproduction or overproduction
Items that can be ordered on a JIT basis
Excessive spare parts; parts sitting in storage facilities
Paperwork/email to be processed
Unutilized equipment
Excessive ‘safety’ stocks
Stock queues before machines
Any material or supply in excess
Causes
Large volume shots. Batching. Supplier ‘minimum order quantities’ or buying extra ‘because it’s a good deal’. Equipment breakdowns. Weather (preventing processing). Inaccurate forecasting. Ordering more than needed ‘in case,’ or items that ‘might’ be needed. Quality or yield problems. Inconsistent rock supply.
6. MOVEMENT
What is it? Unnecessary movement, movement that does not add value, movement that is too slow or too fast. Operators making movements that are creating no value. We can also identify waste in the motion of machines & equipment.
Quarry / Mine Examples:
Excessive walking - between work stations, to look at online information, to get a tool or materials
Moving to catch up with production
Driving to job locations or to get supplies/raw materials
Awkward loading patterns
Searching for tools, parts, papers which should be clearly labeled with a location
Changing locations for meetings
Operators walking long ways for meal breaks or hand off
Lifting
Reaching for things
Haul trucks navigating suboptimal roads
Causes
Poorly located tools; disorganized tool boxes. Feed conditions causing uneven screen load; unused screen area. Ordering more inventory than needed, maintaining & marshalling it. Lack of ergonomic design & placement. Loss of material (poor fitting skirts, holes, flashing; transfer points). Unclear locations for parts; disorganization. Failure to review mine/quarry layout & adapt as material stripping proceeds. Trickle feeding/failing to choke cone. Road conditions, surfaces & obstacles.
7. MAKING DEFECTIVE PRODUCTS
What is it? Waste related to costs for inspection of defects in materials and processes, customer complaints, scrap and rework/repairs. Anything that does not meet customer specifications or requirements of form, fit, function, or timing/delivery. Results in inspection to catch quality problems or fixing an error already made (inspection, rework, and scrap).
Quarry / Mine Examples:
Product does not meet customer specifications:
Oversize/fines
Hardness/durability
Cubicity
Late delivery
Recirculation - material through the crusher more than once
Costs of processing complaints
Making large lots of bad product instead of catching a problem after one or two units
Fixing errors made in documents
Dealing with complaints about service and/or repeating the service
Making incorrect documents
Repairing trucks/equipment after oil overfills; replacing seals after over greasing
Using defective raw material or parts
Repeating an equipment repair done incorrectly or with wrong/failed part
Causes
Variance in: raw material, processing methods, equipment maintenance or setup, employee training/experience, customer communication. Stockpile segregation. Wrong cone liner configuration or closed side settings; wrong screen cloth. Using work arounds instead of addressing root cause. Poor drill patterns. Poor quality or defective parts.
Which do you have in your operation?
What’s missing from these examples?
*adapted from previous article to include all 7 wastes & more examples