It is no wonder our mines struggle
with efficiency. Whose fault is it that equipment routinely falls short
of predicted performance? Mine schedules or new development's mine plans
are often not worth the paper they are written on.
Last blog I introduced a spreadsheet
provided by a supplier with a prediction of performance of a 62.7 CuM
shovel.
Is it really the supplier’s job to tell you how well the
particular piece of equipment will perform on your minesite? Well….. yes
and no. You would expect them to know how it performs on other sites and
this would be valuable input for you to use and relate to your own minesite
idiosyncrasies. Right or wrong they simply do not know how their
equipment performs (and the fact that we do know is a major threat to them).
As I said last week, in a perfect world our suppliers would take an interest in
after-sales performance but over the last ten years most haven’t. So long
as it is running it is doing OK.
The productivity forecast by the
shovel OEM was sent to the mine presumably for planning purposes and I wanted
to run through this to show why mines routinely miss production targets.
Last week I looked at the truck capacity and the dipper payloads. This
week I want to look at hours and overall productivity.
The annual hours is an area where you
would expect the supplier to have a good idea on performance and I suspect they
do. The problem is that in many cases the hours worked are so low the
supplier is probably embarrassed to say what they know. You see, if there
are two suppliers in a tender for a loading tool and one decides to be honest
and tell the mine what they really know then they will probably lose the
tender. This is a simple fact. Most mines don’t check information
supplied by OEM’s and just simply believe the lies and or guesses. The
end result is that the mine receives two sets of fictitious performance
predictions. Mines only have themselves to blame for this
situation. The data exists and there are people around who do know how to
analyse it.
Average work hours around the world
for the particular model shovel are 4,599 per annum. The OEM predicted 5,098
(Op hrs * Job Efficiency * Truck Presentation). They either don’t know
(which questions their competence) or they are providing numbers they know are
wrong. 500 hours in a year is a lot. I will look into the reasons
why these hours are so low in a future article.
Given the poor performance the
supplier is predicting for payload (although given what is happening elsewhere
with truck loads being well below the nominated capacity, the average may need
to be lower still) and the high hours (relative to other shovels) the end
result of 21.8 MBCM places this shovel in the 83rd percentile of performance
for this make and model normalised to 62.7 CuM. Now this is fine and I am
sure the mine would love to use this number in their mine planning but if they
plan for it and don’t get it the repercussions may be significant. I
understand that the OEM has not provided a guarantee but the mine really needs
to know (with some degree of authority) whether the OEM thinks this shovel,
working at the particular mine, loading the nominated trucks can perform
consistently in the 83rd percentile. Interestingly enough best practice (approx
95th percentile) for this model in the geographic area they are is only 18 MBCM
so you work out for yourself if they will get 21.8 MBCM.
Following on from this I revisited
another OEM’s calculations for a dragline bucket’s performance this week and
saw a much more professional approach to giving the mine something to work
with. In this case the supplier had been given copious data by the
mine. However, the supplier’s understanding of minesite operational
issues and a specific data issue still resulted in them arriving at the wrong answer
for recommended bucket capacity. Now this doesn’t seem too bad, except if
the mine accepted the recommendation they would have purchased a bucket which
was more than 10% too big for the machine.
I can’t believe how difficult this is
for the mines!!! It doesn't need to be. In this case we had told
the supplier that the payloads from the monitor were flawed!! This is the
main reason why we are encouraging mines to not just give their data out to
anyone. You need someone who knows the data and the issues with it.
You really want to come up with the right answers. We encourage mines to
tell the suppliers to contract an independent third party to do the
analysis. At least then the mine can have confidence in it.
Graham Lumley
BE(Min)Hons, MBA, DBA, FAUSIMM(CP), MMICA, MAICD, RPEQ
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