Bengħajsa quarry could undermine adjacent solar farm

The owners of a solar farm just 80m off a proposed quarry in Bengħajsa, near Birżebbugia, has expressed concerns a new hardstone quarry would disrupt undermine the farm’s foundations and cover panels with dust.

Mediterranean Energy Limited said the hardstone quarry proposed by Paul Falzon over a 6,200sq.m plot of agricultural land just off Triq il-Fortizza, said “the continuous and unpredictable nature” of vibrations caused by quarrying “will disturb the present stability of the solar farm”.

The quarry would lie less than 200m away from the shoreline, 600m from a recently approved family park and immediately next to the 29,000sq.m solar farm which produces enough clean energy to power some 760 households annually. 

MEL, which is owned by the Hili Group, said the quarry vibrations could destabilise the slopes and retaining blocks of the solar farm, which was itself developed on a disused quarry and in-filled with coal ash by Enemalta. The site of the solar farm had been used as a landfill for the disposal of pulverised fuel ash from the Marsa Power Station up until 1992.

The previous use of the site as a quarry was the reason why the site qualified for development as a solar farm as required by the policy limiting solar farms to disused quarries. The retaining walls became necessary when it was discovered that part of the site was originally rehabilitated inadequately with a very thin layer of inert waste. No earthwork leveling was allowed, so as not to disturb the coal ash beneath, leaving MEL no option but to erect a retaining wall directly on the coal ash, in order to obtain an acceptable slope for the PV panels to be installed.

“It is predictable that the quarry vibrations will destabilise the slopes and the retaining blocks of the solar farm itself since their foundations lie directly on the coal ash contained within the lower coralline formation below ground level of the original quarry,” MEL contends.

Moreover to prevent the coal ash from contaminating the water table it was also capped by a layer of impervious membrane. “Extensive vibrations will disturb the underlying coal ash and render the impervious membrane susceptible to joint discontinuities,” MEL said, leading to water ingress and eventual percolation through the coal ash.

The solar farm owners are also concerned that the quarry will result in a drastic reduction in the power production from the solar farm, due to the deposition of dust of the PV panels. “There is no practical solution to keep thousands of panels free from dust with a quarry adjacent.”

The Birżebbuġa council is also objecting to the quarry, noting the close vicinity to the family park approved in March 2021, which lies midway between the park and the coastline, separated by a 600m tract of open agricultural fields. “The proposal is not compatible with the rural nature of the area, and specifically the park at Bengħajsa which the Planning Authority has deemed fit to approve,” said architect Carmel Cacopardo, also leader of the Green Party ADPD, who is advising the council on this issue with its objection to the proposed quarry. Nearly 150 residents have already sent their objection to this development.

Hardstone, the demand for which is increasing due to the construction boom, is usually used for the preparation of cement, for concrete mixing and for roadbeds. The stone is then processed into fragments by crushing machines and then sorted according to the particle size.