The analysis of a chemical composition of river waters, load sediments of the small rivers in area of displays of Zn and Pb ores in northern part of Vietnam in 2015-2016 is executed. It is offered to use as additional search criteria probability of overlapping of a river network with tectonic faults P(r|f) and a ratio of the common area of a river basin and its part without expressed channel networks F/F0. It is shown that the probability of detection of abnormal concentration Zn and Pb sharply grows under condition of P(r|f) > 0,6 and F/F0 < 6-7. The physical sense of use of the specified hydrological parameters consists that:
1) the primary aura of dispersion above an ore body is as much as possible kept at the minimal drainage of territory;
2) the secondary aura of dispersion is identified most effectively at overlapping a river network and tectonic faults.

Savichev Oleg G., Doctor of Geographical Sciences, Professor of the Tomsk Polytechnic University Department of Hydrogeology, Engineering Geology and Hydrogeoecology. 30, Prospekt Lenina, Tomsk, 634050, Russia. E-mail: OSavichev@mail.ru

Nguyen Van Luen, Assistant at the Department of Hydrogeology, Engineering Geology and Hydrogeoecology. Graduate Student Tomsk Polytechnic University. 30, Prospekt Lenina, Tomsk, 634050, Russia. E-mail: Luyennv@yahoo.com

Domarenko Victor A., Candidate of Geological and Mineralogical sciences. Associate professor of the Tomsk Polytechnic University Department of Geoecology and Geochemistry of. 30, Prospekt Lenina, Tomsk, 634050, Russia. E-mail: viktor_domarenko@mail.ru