Velardena

WALTER SKINNER'S MINING INTERNATIONAL YEARBOOK 1978: LON-MAJOR NEW PROJECTS AND EXPANSION PROGRAMMES, MINING MAGAZI-NE, JANUARY 1979, P. 68.OF MINING AND MINERAL PROCESSING OPERATIONS, NEW YORK,MCGRAW-HILL, 144 P.MINING MAGAZINE, MARCH 1978, 246 P.MINING MAGAZINE, JANUARY, 68 P.GRUPO INDUSTRIAL MINERA MEXICO S.A. DE C.V., ANNUAL REPORTTO THE 31ST OF MARCH, 1980ENGINEERING AND MINING JOURNAL, IMM: MINING AND PROCESSINGA WIDE RANGE OF BASE AND PRECIOUS METAL PRODUCTS,NOV. 1980, PP. 110-111.