Reclaimed Mining Resources


Since 1996, Clarendon has been developing the technology which would be ecologically and economically viable for recovery of metals from liquid and solid mining tailing’s, flotation tailings and purify acid mine water. Besides the development of technologies for the exploitation of ores with poor metals content, we have developed various technologies for the rehabilitation of degraded areas caused by mining.

Clarendon has experience and expertise in sanitation of mines and prevention of ecological disasters. We have been the main consultants to the government of Serbia in 1996 after an ecological disaster as a result of breaking of the flotation tailings.


As a result Clarendon has developed an environmentally friendly and commercially viable ION Exchange copper extraction technology for copper extraction from flotation and oxide copper tailing’s and acid mining waters, and a complete multi-phase (pre, resource preparation and copper recovery phases) technological process for copper recovery; implementing third party and ION Exchange technology in the process.


Separating commercially valuable minerals from their ores is a process that aims to produce final product by economically justified methods

Mineral processing can involve four general types of unit operation:

  • commination – particle size reduction
  • sizing – separation of particle sizes by screening or classification
  • concentration by taking advantage of physical and surface chemical properties
  • dewatering – solid/liquid separation

To obtain the final product, the most important role in the process is concentration. There are a number of ways to increase the concentration of the wanted mineral. In the case of mineral processing concentration, this is percentage increase of the valuable mineral in the concentrate.

Development and application of new concentration processes using modern achievements in the fields of physics, chemistry, technology, equipment and years of experience and achieved know-how has enabled us to develop our own proprietary technology for metal recovery from resources with low metal concentrations – with focus in the field of exploitation of copper from liquid resources, solid resources, mixed oxide sulphide ores, and special procedures for multistage flotation of mixed ore.


The proposed technology performs separation of oxide copper ore from sulfite copper ore during the resource preparation process and before the flotation process. The ore with sulfide copper minerals goes into the flotation process and the ore with oxide minerals are treated with our LP (leaching and precipitation) technological process for the production of copper powder or copper cathodes.

Using this method of separation of sulphide and oxide minerals reduces the cost of the flotation process, increases the copper content in the concentrate and increases the utilization level of the copper from the ore.


The copper tailings resource from the copper mine contains sulfide and oxide minerals. Sulphide copper minerals can often in part and on the surface transform in to oxide state, caused by exposure to air and atmospheric conditions, thus preventing access to the sulfide minerals beneath the surface layer. Complete recovery of copper from the oxide and sulfide minerals is achieved by the LPF process. This process obtains copper concentrate which contains copper from sulphide and oxide copper minerals.


Dual ion exchange procedure is designed to extract copper and copper powders from acid water that occurs naturally or by hydrometallurgical processes and treatment of ore bodies, solid and liquid tailings.

Depending on the procedure and the characteristics of ore to be processed, obtained is acid water with different copper contents.

For acidic water with copper content below 4gCu / l, double ion exchange process is used.

For acidic water with a copper content of 4-6gCu / l, either the double ion exchange process is uses or only the second ion exchange – fast hardening process is used.

Acidic waters containing copper over 6gCu / l are referred directly to the second ion exchange and direct copper production.

Clarendon was the first to globally apply the Ion Exchange technology for use hydro-metallurgy, as an alternative for copper and other metals recovery to solvent extraction.

Cyanide free process of selective flotation for lead-zinc and copper ores

In the selective flotation process of lead and zinc ores, most commonly applied zinc depressant method is use of cyanide and zinc sulphate. However, technological process with cyanide is increasingly in conflict with the requirements of environmental protection. Furthermore, copper minerals that are found in the lead and zink ores represent a problem as an undesirable content in the lead concentrate.

Recognizing this problem, we developed a new method of selective flotation concentration by applying an effective, non-toxic cyanide-free depressant for Galena “DG/1” and depressant for Zink “DZ/2”. Galena and Zinc depressants are our own patented and laboratory tested products. The use of this method obtains from the ore in a cyanide-free process the following selective concentrates:

  • Copper concentrate with gold
  • Lead concentrates with silver
  • Zinc Concentrates
  • Concentrates of pyrite and arsenopyrite with gold