Mill tailings based composites as paste backfill in mines of U-bearing dolomitic limestone ore

This paper elaborates on the development of paste backfill using mill tailings generated during the processing of a uranium ore deposit hosted in dolomitic limestone. The tailings have been characterized in terms of the physical, chemical and mineralogical properties. Time-dependent rheological behaviors and geotechnical properties of cemented paste backfill(CPB) are also determined. The studies show that the mill tailing has the potential to form paste and the CPB has adequate strength to provide support to mine pillars, roofs, and walls.

Characteristics and dynamic settings of the Central-east Asia multi-energy minerals metallogenetic domain

That more than 82 percent of proved sandstone-type uranium deposits coexist with proved oil-gas or coalfields in the world reflects the fact of coexistence and accumulation of multi-energy minerals including oil,gas,coal and uranium in the same basin.Especially,this phenomenon is most typical in the Central-east Asia energy basins.Across China,Mongolia and some central Asian countries,the giant Central-east Asia metallogenetic domain(CEAMD)stretches more than 6,000 km from Songliao Basin of China in the east to the Caspian Sea in the west.The multi-energy minerals distribution characteristics of the domain include:their spatial distribution is complicated and ordered;the ore-bearing horizon relates closely to the geographical region;the accumulation/mineralization and localization time is the same or close;the occurrence setting and accumulation/mineralization have close correlation;and they have rich provenance for all the minerals.All of these imply that they have close relations between each other under a unified geodynamic background.The exogenetic uranium mineralization process in CEAMD can be divided into five phases using time limits of 100 Ma,(50±2)Ma,20±(2―4)Ma,8―5 Ma.The major mineralization periods and their differences in each primary uranium-bearing basin are identical to the oil-gas accumulation and localization periods and phases in the same basin,and are also in response to regional tectonics and controlled in general by the regional geodynamic environment.For industrial application and commercial exploitation,it is suggested that an important period for coexistence,accumulation and localization of oil,gas,coal and uranium and their interaction mainly occur in the late/last and post basin evolution.Through generalized analysis and comparison of accumulation/mineralization environment of the energy basins in CEAMD,the authors propose that the relatively stable regional tectonic background and moderate(weaker)structural deformation probably are necessary for formation,coexistence and preservation of large and medium-scaled sandstone-type uranium ore deposits,oil-gas fields and coalfields,while basins in favor of coexistence and accumulation are those intracratonal,intermediary massif basins and corresponding reformed basins.