TORONTO -- Canadian mining companies active in Ecuador took a further stock-market beating yesterday, while saying they are assessing measures adopted Friday by the South American country's constitutional assembly.

"A number of the articles contained in this mandate are very unclear and consequently we are not yet able to fully assess any potential impact on some of our concession holdings in the country," Corriente Resources Inc. of Vancouver stated yesterday morning, before its stock fell 20 per cent on the TSX.

Corriente shares dropped 82 cents to close at $3.28, down almost 70 per cent from $5.49 last week before investors took fright at the Ecuadorian action.

Aurelian Resources Inc., whose Fruta del Norte project is regarded as a major gold and silver find, saw its stock fall $1.31, 26 per cent, to $3.73 as the most actively traded TSX issue yesterday, down from $8.66 last Thursday.

Aurelian said the new mining mandate limits companies to no more than three concessions, meaning it expects to retain Fruta del Norte and two other promising sites and it also "will seek to protect all investments made to date at its other concessions that it has been actively exploring since 2003."

The mandate also imposes an immediate 180-day suspension of activity on mining concessions throughout the country while a new law governing the industry is developed and enacted.