DD, Also not mentioned explicitly, but in the past unprocessed tailings have been mentioned. Most recently:
If that information pans out, I wouldn’t be at all surprised to see a gravimetric Falcon system used to process these tailings well ahead of exploitation on the Caren Mine.
We expect to start mine preparation during the second week of June. Mine preparation will take approximately two months.
We have conducted metallurgical test runs at recognized laboratories in Chile and Peru. These have resulted in an average gold recovery of over 90% from concentrated ore obtained by a gravimetric Falcon system. Based on this, AURYN expects to produce a total of 5,000 troy ounces of gold in 2016 and over 25,000 troy ounces in 2017.
http://aurynmining.com/category/news/
Also note:
Fortuna de Lampa is an old mine that was active during the 1960’s. Reports from those days show a total production of 280Tn of concentrate grading 92.3 g/t Au, 133,7 g/t Ag and 0,8 %Cu.
ALTOS DE LIPANGUE
It may be a jump, but the report from the 60’s specifies “concentrate grading 92.3 g/t” which suggests to me this was from floatation and/or gravitational methods not employing chemicals. Older reports suggested tailings on MDMN and CDCH claims contained as much as 5 g/t Au. Artisanal methods using primarily “dry washing” or floatation (edited by me), if used in the 60’s, would make these tailings very economical to process quickly with a system such as a Falcon Gravity Concentrator http://www.seprosystems.com/sepro-mineral-systems-brochures