Holding the mighty rock together

By Dhaneshi YATAWARA

It is amazing how a giant rock standing in the middle of a great plateau has mesmerised humans for many centuries. Kings were enthralled by its natural fortress-like structure and the creations of their artistes and architects still astound visitors from all over the world.

This rock, a unique witness to the great Sri Lankan civilisation, stands in Dambulla of the Matale district and is known as Sigiriya or the Lion's Rock. It was the capital city of a patricidal king, yet not a single trace of this brutality is evident in the fortress.

As history depicts, this city of ruins which we see today is what King Kashyapa built during his reign from 477 BC to 495 BC. King Kashyapa killed his father King Dhathusena to grab the kingdom and later cast out his brother Mugalan. Fearing the return of his brother with a vengeance, Kashyapa selected the Lion's Rock to build his fortress, according to the Mahavamsa, the chronicle of Sri Lanka's history.

During the 11 years that Kashyapa resided in Sigiriya, he created exceptional splendour. In 495 BC, after a battle that lasted for a short period, Kashyapa was killed and Mugalan returned Sigiriya to the bhikkhus to which it had belonged.

The Sigiriya Rock, proof of the great Sri Lankan civilisation, is aging today. As no law stands above the rules of Mother Nature, this solid rock fortress is peeling off through a procedure scientifically known as weathering. Slabs of loose rock have been found on Sigiriya by geologists.

"First this was noticed by Dr. Shiran Deraniyagala who informed the Geological Survey and Mines Bureau to come up with a mechanism to preserve this historic site", said Chairman of the Geological Survey and Mines Bureau (GSMB) Dr. N.P. Wijayananda explaining the launch of a joint expedition of science and archaeology.

Historic value

"This is natural and it happens to all rocks. But considering the historical value of Sigiriya and the fact that thousands of local and foreign tourists visit this place, it was important to stop these loose rock slabs from falling", Dr. Wijayananda said. If such rocks fall on a visitor, it could mean danger for every single tourist to Sigiriya", he said.

Weathering is a natural phenomenon where rocks, soils or minerals break down through contact with the atmosphere, plants, animals or water. This happens in two ways - i.e. chemical weathering and physical weathering. Chemical weathering happens as a result of the direct effect of atmospheric or biologically produced chemicals.

Physical weathering is the break-down of rocks as a direct result of environmental conditions such as heat, water, pressure and in some parts of the world, ice. The material left over after the rock breaks down combined with organic material creates soil.

Preserving the Lion's Rock - the hardened magma plug that rises 1,214 feet above sea level - against weathering is not a simple task. "Initially we identified six spots on Sigiriya with loosened rock. For the past 12 years we have been carrying out the renovation and identifying risky spots on the rock", Dr. Wijayananda said.

With many ups and downs, the GSMB has now completed the task with the support of the Ministry of Environment. "The rock has been saved entirely with our indigenous expertise. The work itself is a wonder. The path to success was not a bed of roses for the GSMB."

Several offers

"There were several offers from other organisations to carry out this task using huge scaffolding built from the bottom of the rock, which was too costly. So we developed, with our experience in working with mines, a much more eco-friendly and cost-effective method to meet the challenge", he said.

Armed with a team of five or six members, including two senior technical officers, R. Manchanayake and B.D. Sirisena who had much experience at the Kahatagaha mines, the project to hold Sigiriya in one piece was launched with Udaya de Silva, Assistant Director (Geology) of GSMB under the instructions of Chairman Dr. Wijayananda.

The skilled workers were those who had retired early from the Kahatagaha mines and were familiar with such geological situations. The final part of the project, carried out over the past one and a half years, has cost Rs. 52 million.

The weathering stone patches had to be anchored to the mother rock using stainless steel rods. "Earlier anchoring was done using steel rods, but with time steel erodes. Thus we had to use stainless steel that will last forever". Senior Technical Officer R. Manchanayake said.

It was a tedious task mostly carried out manually as machines would create a vibration that could have destroyed this architectural masterpiece. The workers had to embed stainless steel rods in to the loosened rock until they reached the mother rock, to provide stability. All the work had to be done manually. While working on the sides of the rock, the workers had to hang on to ropes with safety belts around their waists.

Platform eroded

The GSMB was instructed to repair the pocket of frescoes of which half remained closed for a long time as the platform had eroded. The GSMB team, after putting up a better platform under the frescoes pocket, renovated the entire viewer's platform. "We had to seek special permission and work in the nights as well since there was a lot of work to be done", Dr. Wijayananda said.

Day and night the GSMB staff toiled to preserve the rock with nothing but their bare hands. The staircase to the granite peak has been expanded, doubling its size. During renovation, it was observed that the outer side of the mirror wall was exfoliating. Again, setting up another working platform outside the wall on the steep rock,the GSMB team started pasting the patches. It was then (2004) that they came across some undiscovered frescoes drawn outside the mirror wall. It was a magnificent archaeological finding for Sri Lanka in recent history. "We cannot stop the weathering of the rock, but what we can do is anchor the loose rock to the mother rock where necessary. We need to periodically monitor and identify such spots", Dr. Wijayananda said.

He also highlighted the importance of mitigating the physical weathering of the rock by tree roots by uprooting trees from rock surfaces. "This is important because, though the trees provide shelter to the rock against the harsh sun, the damage done by the roots is far greater", Dr. Wijayananda said.

Today, with the effort of the GSMB team under the Ministry of Environment, Sigiriya has become a safe place to visit. It is the efforts of our brave men from villages which continue to prove that Sri Lankans still have the knowledge and courage of our predecessors who gave us such wonders of the world.