Generally, I liked to sample fuel transport tanks BEFORE they broke the seals and unloaded. I tried to always have someone of my maintenance crew present when the trucks arrived. My guy observed the truck driver break the topside hatch seals and then drew samples off the bottom of the tank. Samples were physically inspected onsite and then sent to a sample test lab for a full analysis. This did not always get done, especially at the start of any given project, or at the end as well.
Exaample of getting burned: A newer Cat 245 excavator finished on another project in Maryland arrived on a job in West Virginia where I happened to be the Maintenance Manager. It seemed to operate alright and after final assembly, it began to work loading some 777 Cat end-dumps. within that first shift, the excavator engine began to act up. A check of the fuel filters detected visible water and unknown material in the filter pleats. Complete filter changes were performed as was a drainage of the fuel reservoir and cleaning all fuel feed and injection lines. Engine ran fine for an hour or so, then back to problems.
Local Cat house sent down a tech and he replaced the pump and injectors as well as doing everything we had done the day before. However, my master mechanic drew me aside and stated that on the previous project, he knew that the purchasing agent had made a deal with their fuel supplier to purchase returned home heating oil. This fuel was collected as part of a program the fuel supplier had with it's residential customers every fall before winter arrived. The supplier then offered it to the PA at a greatly reduced price and he bought several loads before the job was completed.
Problem was, all the heating oil was severely contaminated. The 245 HEUI system demands very clean fuel and it was overwhelmed to destruction. I had the fuel supplier for our project drain all the fuel from all the units we had and then refill them with new fuel. I also implemented a new fuel policy for our job that required fuel sampling, and a rigid changing of fuel filters at every 250 hour maintenance interval. Also required that adequate amounts of fuel conditioner be placed in unit fuel tanks per manufacturers instructions. (Conditioner manufacturers) This was winter 1998 and a exceptional cold front intruded over a weekend. We were the only earthmoving company operation 100% that Monday morning. Fact was, we were about the only outfit with diesel engines operating in a one hundred mile radius of the project. Even our fuel supplier could not get his trucks out as they were all froze up. Our corporate Equipment Manager called up from Dallas and stated comfortably that he expected we were shut down like everyone else in the area. Boy, was he surprised to hear that we were in full production with zero problems. I still have the letter of commendation our project manager wrote to me for enabling us to run. It a week or more before many companies in the area were able to get back up and running.
Another example: On a contract coal mining operation in West Virginia, The new corporate Equipment Vice-President and I were hired within a month or so of each other. He was a great friend and we had worked together before. We soon found that conditions with the equipment and lack of maintenance were far worse than he had so far known. So far as the fuel was concerned, we were burning about 20,000 gallons a day. We had 50,000 gallons of storage onsite. The storage system did not have any filtering in-line anywhere. The fuel arrived at all times of day and night and no one supervised the unloading. We got away with that situation during the summer and early fall, but before we could get a large commercial filter unit rigged up, winter hit and once again, a cold front moved in over a weekend and we came dangerously close to a shutdown because of lack of fuel. The current fuel transport firm had all it trucks froze up and could not meet their delivery goals.
Found out later (why is it always later?), that the fuel they were delivering was: "barge bottom sludge." The fuel was shipped out of Texas by barge up the various rivers to a fuel dock on the Kanawa River downstream from Charleston, WV. When the removal of fuel from the barges reached a certain level, the pumps were shut off and the "empty" barge moved aside to provide room for a full barge at the receiving dock. The remaining bottom fuel was then removed into a special tank that was designated to hold contaminated fuel. We paid that trucking firm for the fuel, not the people that delivered it upriver. The trucker naturally bought the cheapest product he could find and delivered it to us. It took me a while to catch on and get the straight story, but in a couple of weeks I fired that outfit and contracted with a trucking firm out of Charleston, actually the same company that saved our bacon by being able to deliver during that cold spell. Much gnashing of teeth and hair pulling later, corporate finally settled down and admitted that I made the right move.
I then initiated the same fuel system maintenance programs as I had done on the other project and, with the final assembly of the large filter at the fuel farm our troubles were over as regards fuel. The only reason I can figure why we didn't a greater problem with fuel before that was that we were using so much very quickly.
Lost production time due to fuel problems is a large number no matter what size the contractor or end user is. It pays off to have strict fuel purchasing and delivery systems in place right from the get go. I could probably write all night long on this subject with experiences concerning over 50 years in the heavy earthmoving and mining industries.
5 gallon cans of fuel are a bad move. Probably the best way to contaminate fuel there is. Use a tank mounted in the bed of a pickup, with a reasonably priced filter and electric pump assembly if you are into small quantites. I would not recommend sampling any reservoir of less than 4000 gallon capacity. But in that situation, demand sample reports from your supplier. If he does not want to do that, find a supplier that will.
Good luck to all.