War over chippings from Shai Hills - GHA allays fears

BY: Della Russel Ocloo
 Some of the aggregates (chippings) at the Gokay Quarry at Shai Hills
Some of the aggregates (chippings) at the Gokay Quarry at Shai Hills

The Ghana Highways Authority (GHA) says it has taken steps to rectify the ambiguity in the contract for the Tema Motorway Roundabout Interchange project which excluded the Shai Hills from areas from where aggregates (chippings) for concrete construction works could be procured.

According to the acting Chief Executive Officer (CEO) of the GHA, Mr Ernest Kingsley Arthur, it was never the official position of the authority to exclude materials from the area in the contract since it had not conducted any alkali reactive tests on aggregates from the hills.

“No contractor has been asked not to buy aggregates from the Shai Hills and so we find information circulating to that effect as unfortunate,” he said and added that the position of the GHA was that contractors and project engineers could use aggregates that met their specifications.

The alkali-silica reaction test (ASR) in rocks refers to "concrete cancer", which is a reaction that causes swelling that occurs over time in concrete.

Structural problems

ASR could lead to serious cracks in concrete and result in critical structural problems that could force structures to be demolished.

Members of the Shai Hills Quarry Owners and Operators Association in the Shai Osudoku District in the Greater Accra Region have been up in arms against the GHA over the past two years following communication it had received from project engineers working on various projects in the country to the effect that aggregates from the area were not safe to be used for casting concrete in construction owing to high alkali-silica levels.

According to the group, the unsubstantiated suspicion has had a negative impact on their operations with the result that the future of more than 2,000 workers in about 36 quarry sites in the Shai Hills was on the line.  
 
Meanwhile, Mr Arthur had stated that the GHA had written to the contractor that aggregates from the Shai Hills could be used in the project works provided they met the contractor’s technical specifications.

Contract

The technical specification agreement in the contract drafted by the project consultants, CTI Engineering International Company Limited, has detailed that aggregates from the metamorphic rock source in the Shai Hill area should be excluded from all major concrete structures.
 
According to the agreement, a copy of which is available to the Daily Graphic, both “coarse aggregates (stone) and fine rocks (sand) shall be tested for potential alkali-silica reactivity”.

A letter from the Resident Supervisor, Mr Masaki Ogasawara, on July 27, 2018 to the CEO of the GHA, pointed out that materials from Shai Hills should be excluded from the project on the advice of the Ministry of Roads and Highways and the GHA during the critical stage of signing the agreement on November 2, 2017.

The letter has created apprehension in the construction industry, with many contractors said to have stopped buying aggregates from the area owing to what has been described as a safety precaution.

While the project consultants and the Building and Road Research Institute (BRRI) of the Centre for Scientific and Industrial Research (CSIR) maintain that the aggregates had high alkali-silica levels and could cause possible structural collapse, Mr Arthur on the other hand has debunked the assertions, saying the GHA had not conducted any tests to merit that conclusion.

“It is not the official position of the GHA and we are equally taken aback that such a clause found its way into the project agreement.
“We find the action unprofessional and have written to the project consultants and managers drawing their attention to an additional provision in the contract that supersede the exclusion provision,” Mr Arthur said.

Test results

Independent tests on the aggregates carried out by a leading international construction firm, Eiffage Group of France, in France on November 11, 2017, to determine the quality, strength, alkali and magnesium levels gave an indicative level of 0.008, thereby signalling that the aggregates could be used in any kind of construction work.

The Daily Graphic has in its custody a copy of the test result certified by internationally acclaimed engineering firm, AECOM, which is also the project consultant for the ongoing new Tema Port project.
 
Similar tests carried out by the Ghana Standards Authority (GSA) on October 30, 2017 on aggregates from the Shai Hills indicate their “suitability for construction purposes”.

Quarry owners

Members of the association have argued that in the recent past chippings from the Shai area were used in constructing the Kwame Nkrumah Circle interchange, portions of the Kasoa interchange and recently the Ecobank head office building at Ridge in Accra.

Speaking to the Daily Graphic during a tour of some of the quarry sites at Shai Hills, the spokesperson for the Quarry Owners Association, Mr Michael Kumah, said the group was surprised by the decision to exclude its products in the Tema Motorway roundabout project, considering the fact that the area was just 22 kilometres away from the project site.

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