Abstract
This work was conducted at a large gold mine in Paracatu, MG, Brazil, between March 2000 and November 2005. The waste rock studied was a phyllite which contained (in addition to gold) sulfides such as pyrite and arsenopyrite. The objective was to evaluate the survival and growth of plant species on different combinations of plant growth substrate layers deposited over the spoil. Each combination tested consisted of a cover-layer and a final sealing-layer, both deposited over the remaining, slightly-weathered rock spoils. The treatments were as follows: (T1) a cover layer with 50 cm of partially weathered spoil (B1) with lime added over a compacted sealing layer with 30 cm of B1; (T2) a cover layer with 25 cm of limed native soil over 25 cm of limed B1 over a compacted sealing layer of 30 cm of B1; (T3) a cover layer with 50 cm of limed B1 over a compacted sealing layer of 20 cm of limed soil over 20 cm of unlimed B1; and (T4) a cover layer with 25 cm of limed soil over 25 cm of limed B1 over 20 cm of compacted limed soil over 20 cm of unlimed B1. The plant species used were Acacia farnesiana, A. holosericea, A. polyphylla, Albizia lebbeck, Clitoria fairchildiana, Flemingia sp., Mimosa artemisiana, M. bimucronata, and Enterolobium timbauva. Experimental data included diameter of the stem collar (DC), plant height, and survival counts. The greatest survival rate was observed with T4, at 80%. In general, M. bimucronata and A. farnesiana species showed the highest survival rate. The Scott-Knott test a p < 5% indicated that A. holosericea had the greatest growth-response, while A. polyphylla, Flemingia sp., and E. timbauva exhibited lower growth rates. The bioavailable soil As content from (T1), (T2), (T3), and (T4) was 14.69, 0.00, 10.41, and 0.00 mg dm -3 , respectively. These experimental results support the conclusion that presence of native soil is essential for establishment of plants and minimization of plant toxins like As in mine reclamation efforts, and that appropriate implementation of layer combinations such as studied here allows greater survival rates and biomass gains.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal American Society of Mining and Reclamation
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
