Her mission, backed by five Catholic bishops, was to persuade the directors of one of Britain's biggest multinational corporations that its quest for gold in the Philippines mountains will destroy the culture of an ancient tribal people.
RTZ-CRA, the biggest mining company in the world, wants to search for gold and other precious metals across hundreds of thousands of hectares of the sacred homeland of the Subaanen tribe.
Sister Margaret who lives among the tribe, said: "If the company goes ahead, I would be terrified that it would be the death of them. Without land their spirit will be destroyed and they will be scattered."
The British company has applied for exploration rights in 600,000 hectares of the Zamboanga peninsular on the island of Mindanao, in the southern Philippines. The mountains are the ancestral lands of the 300,000 Subaanens, originally a hunter-gatherer society which now cultivates corn and rice. As animists, they believe the living soul of their god Diwata is present in natural phenomena like the sky and mountains. Any desecration of their land would be seen as an attack on god.
According to the London-based priest, Frank Nally, of the Columban Fathers, the normally placid Subaanens are poised to resist any mining operations by RTZ. Father Nally, who spent four years working among the Subaanens, said the tribe had been angered by previous damage to their homelands caused by logging.
"Within a living generation, the extent of the destruction is very evident to the people. I think that is why they are going to resist any other incursions because they have seen what has been done already," he said.
In particular, the Subaanens fear for the future of Pinukis, the holy mountain, where their shamans go for prayer.
Sister Margaret's appeal has struck a chord in London where the World Development Movement, Survival International and the Catholic Association for Overseas Development have formed a joint campaign to stop the project. She brought to London a letter written by Zacharias Jimenez, the Bishop of Pagadian, in the Philippines, for RTZ-CRA shareholders. He said: "Since the company have the right to expatriate all the profits, you the shareholders will probably earn some money."
But he added: "Our rivers and seas will become polluted, our mountains will become deserts and our ricelands poisoned. Our forest birds and animals will become extinct. The very existence of the Subaanens, a gentle and beautiful people, will be put at very high risk."
According to the Philippines constitution, tribal people have rights to their ancestral lands. But these rights have never been enshrined in law. The Philippines government is anxious to exploit mineral resources. Two years ago, it introduced the Philippine Mining Code, with the intention of encouraging foreign companies to help it realise its mineral wealth.
However, despite protest marches and petitions opposing the exploration plans, RTZ believes its project can benefit local people, bringing jobs, hospitals and schools.
A company spokesman said: "The geologists who have gone into this area have talked to representatives of many of the communities and they are continuing their discussions with a view to ensuring that their rights and aspirations are taken account of," he said.
He stressed that if the project went ahead only a "tiny fraction" of the area under exploration would be mined.Reuse content