WHEN the International Monetary Fund recently announced it had granted Bolivia another $60 million loan to support its 1991-92 economic program, few in the United States noticed it was another landmark on the road to economic recovery for one of the continent's poorest countries.Moreover, it underscored the successful reform policies of a former radical leftist, President Jaime Paz Zamora. Once strongly anti-American, the Bolivian leader has changed into a moderate, capitalist-oriented statesman. Since launching its economic reform program in 1985 during President Victor Paz Estenssoro's tenure, Bolivia has made what the IMF terms "substantial progress" in strengthening its balance of payments and in first reigning in, then eliminating, hyperinflation. At one point in the mid '80s, Bolivia had a runaway economy with a world-record inflation rate of 26,000 percent annually. Since the program began - drawing on the advice of Harvard University economist Jeffrey Sachs, among others - the country has achieved sustained economic growth while undertaking broad structural reforms. In 1990, the real gross national product (GNP) continued to grow at about 3 percent annually, while inflation shrunk to a surprising 18 percent. President Paz Zamora, who took office in 1989, soon realized that the 2 to 3 percent growth between 1987 and 1990 had barely kept up with a booming population. To avoid a social crisis, the government set out to attract foreign investment to boost economic growth to 4.5 percent a year. Among other measures, it enacted a new law to promote foreign investment and a new mining code to allow private capital from abroad to operate joint ventures with state-owned oil and tin companies. By lifting all curbs on entry and exit of capital and on remittances of profits and dividends, Paz Zamora has managed to turn the economy of Bolivia upside down. In the first semester of 1990 only, mining exports increased to $202 million, representing some 46.7 percent of the country's total exports. Import tariffs were reduced and interest rates on development loans were freed. Legislation was passed to strengthen administrative systems and set up a more autonomous central bank. Bolivia has been a pariah among Latin American nations as far as investment was concerned. Now it has become attractive terrain for foreign capitalists. However, Bolivia's longstanding tradition of political and economic instability has failed to attract foreign investment in the quantities sought by Paz Zamora. Recently, he got another pat on the shoulder from the Bush administration during his visit to Washington, along with promises that investors would be encouraged to look into the country as a pote ntially good partner. Others are not so optimistic. Political Risk Services (PRS), a US investment forecasting firm, has warned that "the process of shifting economic activity from the public to the private sector, the need to close many tin mines, and the disruption of the profitable narcotics industry complicate the implementation of the recovery program." BOLIVIA'S per capita income remains one of the lowest in Latin America, and its economy is highly dependent on agriculture, despite the importance of mining and hydrocarbons. PRS has also noted that "the government is still struggling to establish the basis for economic growth and the creaton of jobs." Still, Bolivia has experienced a quiet economic miracle, largely ignored by US media. In March 1990, Bolivia obtained an agreement on external debt relief from its Paris Club creditors and subsequently extinguished about $56 million of its commercial bank debt through an imaginative debt-bond exchange, which will also allow the country to improve environmental protection programs and implement children's health plans. These unusual events went almost unreported in the American press, despite the drop in Bolivia's foreign debt, because of its debt restructuring efforts, from $5.6 billion to $3.5 billion. In 1991-92, the government expects to eliminate the balance of the private bank debt of slightly more than $200 million. Although the country still suffers from a deterioration of some 5 percent in its terms of trade, the government expects that to be more than offset by an increase in private and public capital inflow. In the context of the southern cone of South America, only Chile, which has the region's healthiest economy and recently was granted a 19 percent reduction in its foreign debt, can claim a similar set of achievements. In Bolivia's case, the transformation is all the more remarkable because the country has traditionally been ranked as a poor country with limited economic and social resources. Ironically, some of Bolivia's far richer neighbors, like Argentina and Brazil, are still struggling to get back on their feet. Many of their problems seem to stem from the persistent nationalistic policies of the past, which President Paz Zamora has swept under the rug in favor of a far more pragmatic stance. Perhaps the Bolivian example will persuade the staunch defenders of old-fashioned nationalisms that the time for integration and reform has finally come for everybody in Latin America.