An effective spares program is your best defense against unplanned and extended downtime. Often times saving a couple of days of run time over the course of a crushing season will pay for the cost of stocking the necessary, and sometimes even the unnecessary parts.
The most commonly used model for a crusher spares plan begins with categorizing your operations parts into four areas. The goal of this exercise should be to create an inventory of the right parts so as to minimize the potential of extended downtime, while at the same time not tying up all of your cash in parts that are not being used. The four categories are as follows:
These types of spares are usually commodity type spares that are used in multiple locations on a crusher, and fail or wear out on a regular basis with little or no predictability. Suffering extended downtime when one of these parts fails is both frustrating, and demoralizing. V-belts, bearings, conveyor components, toggle plates, and fasteners are some examples of critical spares.
To state the obvious, critical spares need to be in stock and on site.
Typically, these types of spares wear out in predictable time tables. Usually, these parts are changed out on planned maintenance days. Extended downtime as a result of these parts failing is most often a result of poor planning or communication between operators, purchasers, foreman, and/or suppliers. Crusher manganese, screen cloth, and wear rubber are some examples of operational spares.
These types of spares need to be available on site when needed. Proper understanding and communication of lead time, and expected wear life is the key to staying ahead of demand for these parts. How and where these parts are stocked depends on any number of factors. If your company has multiple spreads with common operational spares, a central stock at your home shop may make sense. If the crushing spread is in a remote location, an onsite inventory of is a must. If yours is a smaller operation, you may want to talk to your suppliers about what they typically carry for stock on these parts.
As the name suggests, capital spares require a significant cash outlay to purchase, and rarely need to be used. Most often, you know well in advance of the part actually failing that the part is in need of replacement. Whenever possible, these parts should be changed out in a proper repair facility so as to minimize exposure to the elements and possible contamination of other integral parts. In some cases, these major overhauls have been done in the field; just understand that logistics costs (costs of shipping parts, tools, and/or manpower to site) may balloon in these instances.
Unless vehicle access to site is restricted to winter ice roads (or some other extreme instance), capital spares need not be stocked by the end user until parts failure and/or its planned replacement is imminent. Again communication is the key; suppliers will typically have limited or no stock on these parts, as such, a factory order may need to be placed so the part is available when needed.
Also known as the, "you've got bigger problems than this" parts. Many a parts person has taken the phone call asking for a part that is available but is not supposed to fail. Most often, shipping the part is an exercise in redundancy as the part will return to the factory with teh piece of equipment, or be followed out to site by a service tech, and, most often, a shopping list of other parts. These failures happen for two reasons:
1. Catastrophic event (i.e. a loader tooth seizing a cone)
2. A piece of equipment has reached the end of its life span (major overhaul or replacement required)
Given the volatile and unpredictable nature of most crushing operations (we are breaking rocks after all), there is no way to predict and plan for every possible scenario that you may face. However, this should not detract from the importance of properly mapping out a spares program. Each season that this plan is reviewed and revised, you will find compounding returns on both of your investments of time and money.
by Matthew Armstrong