SAMPLING Introduction
The process of Sampling involves re-clearing a predetermined
percentage of a cleared area. The percentage of an area to be
“Sampled” is calculated from IMAS 9.20. Sampling is
an external Quality Assurance check, and within the Operation
Emirates Solidarity (OES) project, was identified as necessary
on task sites where for various reasons, only one asset was able
to be deployed during clearance operations, or where a particular
problem had occurred that warranted a more detailed and further
investigation.
Aim
The aim of Sampling is to confirm that the area has been cleared
according to National Technical Standards and Guidelines in provisions
with IMAS 9.20.
General
Although it may sound like quite a simple task to re-clear an
area, because of the legal and contractual obligations of the
contractor, if the sampling process locates items of mines or
UXO within the contractual clearance depth (20cm) then accurate
measurements and recording procedures are vital to ascertain if
the item was in a previously cleared area and what asset(s) were
responsible for clearing the area. These findings will have significant
impact on any following Board of Inquiry investigation.
Procedure
The following is a basic summary of how Sampling is being conducted
within the OES project in South Lebanon.
Once the clearance organisation completes clearance on the site,
the QA completion documentation is completed with site schematic
diagrams to scale using Mapmaker. This schematic diagram is then
plotted into AUTOCAD to scale. The AUTOCAD diagram is then divided
into one metre intervals in both horizontal and vertical directions
resulting in a layout of 1 metre square boxes (see
Annex A).
Each box is then numbered systematically. Once the total number
of boxes is known then this number is entered into the randomizer
programme, which will select a random selection of numbers. These
numbers are then entered onto the AUTOCAD produced diagram in
their appropriate boxes. For more information on random sampling
processes see www.randomizer.org
This then becomes the random selection of 1m x 1m boxes to be
“Sampled”. Once the “Sampled” boxes have
been plotted onto this schematic, the Team Supervisor will plot
the best and shortest access routes to these sample boxes, linking
as many sample boxes as possible to keep the access routes to
a minimum from a 2m wide “Base lane” (See
Annex B).
Once the Sampling Task Dossier is prepared it is issued to the
Sampling Team Supervisor, who will then conduct a reconnaissance
of the site.
After this reconnaissance the Sampling Team will establish a
Control Point as per normal mine clearance operations.
The Team will then proceed to clear a 2m wide “Access”
and “Base” lane on the most appropriate and accessible
side of the site to be sampled.
From this “Base” lane, they then proceed to clear
into all selected “Sample” boxes using the planned
access routes to each sample box. It may be more expedient to
clear 2m access lanes through the area to be “Sampled”
to allow better access to all sample boxes.
All “Sampling” conducted whether it is in access
lanes or sample boxes, is done as per mine clearance to a depth
of 20cm.
Every piece of large metal located within the randomly selected
“Sample” boxes is removed and its size, located depth
and sample box number is recorded. An accurate record of the location
of any and all findings must be maintained on a list. The items
that are physically located are also retained for a period of
at least six months. This enables a cross reference process to
take place.
If a mine or UXO is located within the 20cm clearance depth then
the sampling process stops immediately, for it has completed its
function. The area is then recleared by the clearance organisation
responsible for the primary clearance.
Once the area has been fully “Sampled” and all selected
sample boxes have been recleared and checked the Sampling Team
will conduct a full QA completion on this site with all the relevant
QA/Completion documentation.
Any sites to be sampled will have Community Liaison involvement
throughout the sampling task.
Lessons Learnt
As with most mechanisms there were drawbacks with the devised
IMAS system. The main one was the ratio of access boxes to be
cleared to gain access to the random boxes to be “sampled”.
In other words, the number of boxes that had to be cleared to
reach the sampling boxes was as high as 3 to 1. This made the
process of getting to the sample area a time consuming one, as
the access had to be cleared first and this cleared area does
not contribute toward the required sampling percentage.
To overcome this situation the size of the sample boxes was increased
to 2m x 2m squares. This meant the ratio of access boxes to sampling
boxes was halved to 1.5 to 1. This still allowed for the required
sampling percentage to be achieved but significantly reduced the
amount of time taken in re-clearing accesses to the sampling boxes.
At all stages during the Sampling process markings in the field
are maintained at one metre spaces so that accurate measurements
can be transposed from the field location to the written documentation.
Of course when plotting the sampling plan onto a map everything
is drawn in straight lines, the clearance lanes and sample boxes
are squared off and the plan looks simple but intensive. On the
ground however, there are no straight lines and no flat surfaces.
There are slopes, rocks, humps, depressions and dead ground. This
causes problems when trying to locate the right place to sample
as per the sampling plan, therefore some leeway must be allowed
on site. The main factor is to ensure that the appropriate numbers
of “Sample” boxes have been cleared.
Sampling is time consuming and for the “Sampling Team”
it is difficult to maintain focus when you are clearing an area
that has been cleared previously. |
