Newly obtained results from detailed prospection work in the East Nói Kh«n – Cap Hirt tin occurrence, North §µ L¹t by the authors have been showing:

1. Geological characteristics. In the studied area there are following geological units: 1) Terrigenous sediments of the La Ngµ Formation (J₂ ln); 2) Diorite-granodiorite of the §Þnh Qu¸n Complex; 3) Mainly felsic volcanites of the §¬n D­¬ng Formation (K₂ ®d); 4) Hypabyssal intrusives of supposedly Late Cretaceous age; 5) Alluvio-deluvial Holocene mixed sediments

2. Fissure-fault system characteristics. Four main fissure-fault systems are developed in following directions (in ascending order): sublatitudinal, northeast-southwest (30-40^o), northwest-southeast (320^o) and sublongitudinal; among them the northeast-southwest fault system controls the studied tin ore filed.

3. Alteration characteristics of surrounding rocks and manifestations of tin mineralization. Surrounding rocks of tin ore bodies consist of volcanites of effusive and subvolcanite facies, that were altered in different degrees. The ores form zones, including veins, micro-vein nets of quartz-tourmaline, quartz-tourmaline-cassiterite, quartz-sulphide-cassiterite, prolonging in the northwest-southeast direction (East Nói Kh«n) and sublatitudinal (Cap Hirt).