In these very competitive times we need to question the value of every dollar invested in managing assets. Is it time to scale back Oil Sampling for Condition Monitoring of mining fleets?
Oil sampling has become a standard part of many sites condition monitoring regimes. Over time we have seen this grow to include every compartment with the majority of samples taken at either a 250hr or 500hr service interval. In addition some sites have added regular filter-grams of compartments to add another layer of component condition assessment.
Using an Off Highway Truck as an example. Some sites are typically taking, engine oil, coolant, front hub oils (x2), steering oil, hydraulic / brake oil, transmission, final drive oils (x2) and the diff. That’s 10 different samples just on one truck. Let’s assume that all of these are taken at a 500 hr interval (although we know some sites are more frequent) and an average truck does 5500 hrs a year. That equates to 110 samples a year.
On a small to mid-sized mine with a fleet of 40 trucks that equates to 4400 samples per annum. Assuming an average cost of $32 per sample, we are looking at $140,000 for the truck fleet alone just to purchase the oil sample bottles and conduct the oil sample in the lab.
The direct sample cost is only half the cost. Time is consumed taking the sample and reviewing or actioning results. Let’s assume, very conservatively, that for every sample 15 minutes of labour is consumed (10 min in the workshop to label bottles, take samples and prep to send away, 5 min for the person reviewing condition monitoring reports and raise appropriate actions). This equates to 1100 man hours per annum for the truck fleet (733 hrs of tool time and 367 hrs of specialist time).
However in many cases the review of samples do not get the proper attention they need due to sheer volume of data that must be processed and thus, the invested effort is wasted. Often people only action C or X samples yet when you look at the data, there are clear and disturbing trends that are only B samples according to the lab. No action is taken until it is too late.
Now take a step back and consider why we take samples, the ultimate reason is to know the condition of the component. Oil sampling is not the only tool we can use to determine the condition of components and sometimes it is not the most effective. For example, we can use magnetic plugs that provide an instant assessment of condition for final drives and hubs. In the case of the front hubs, often the hub oil is changed every time a sample is taken. In these cases the question must be asked, what value are these samples adding?
In some cases, is it not best to reduce the quantity and cost and then actually extract the value from the most important oil samples?
Clearly oil analysis is an important tool for the right application but the value delivered from every sample must be questioned.
Additionally, a reasonably unknown fact is that around 15% of sample bottles (that are paid for up front in service kits) are never sent back to the lab…..