By George Henry , Gleaner WriterTHE NATIONAL Works Agency (NWA) has urged mine and quarry operators to produce graded material for the construction of roads in Jamaica.
Communications manager at the National Works Agency, Vando Palmer, told The Gleaner that as the agency strives to improve the quality of road construction works, mine and quarry operators have been brought on-board to use only graded material for sub-base and base courses.
He stated that mine and quarry operators met with technical officers of the NWA recently, to examine the country's capabilities and capacity to produce the required graded material from marly-limestone, which, he said, is in abundance in Jamaica.
Mr. Palmer added that marly-limestone, which is used in various parts of the world, has proven to be a quality road construction material over the years and that there are huge deposits in many places in Jamaica.
He said presently there are over 150 licensed borrow pits from which the material is mined for various construction activities, including road construction, and of the 150 borrow pits, approximately 30 are quarries with crushing and screening facilities.
Mr. Palmer pointed out that the quarries provide five million tons of graded material per annum, which is used as sub-base and base course material in the uppermost structure of roads.
He stated that there are advantages to be gained from the use of graded material. These he listed as:
The material, when placed in a grading curve, will achieve required physical properties, such as California Bearing Ratio (CBR), abrasion and soundness.
Sharp angles of the graded material interlocks when compacted.
Good particle shape and distribution is necessary for mechanical stability and the production of dense material. When compacted, the graded material will inhibit saturation of the course base by water.
. Graded material better supports the pavement and traffic by transferring loads from particles.
It is easily placed in narrow roads where the width of the road is not large enough to use motor graders and it is also compatible with JCB's back-end loaders.
Graded material more easily maintains the required thickness of the layer and shape of the road for effective surface drainage; it compacts easily in thin layers, even with static rollers.
And very importantly the National Works Agency will save 30 per cent on material and cost.
However, according to Mr. Palmer, when mine and quarry operators met with officers, they indicated that while they are not opposed to the use of graded material, as part of the new thrust of the NWA, they needed to be assured that after they have acquired the necessary machinery to produce the material, they would not be left idle.
Mr. Palmer pointed out that the NWA is to meet with the mines and quarry operators soon to bring them up-to-date on the estimated quantity of graded material that would be required per year. This, he said, would be to ensure that they get a much clearer understanding as to the amount of the product they would need to produce on a yearly basis.
He said the idea to have the operators produce the material for road construction forms part of the NWA's move towards International Standard Organisation (ISO) certification.
