The ponds enriched with soluto (pregnant ponds) are crucial in the mining process. They are used to store chemical solutions containing gold or copper. Due to the aggressive nature of the stored chemicals, leaks in these ponds are not accepted. Therefore, the pond generally consists of two layers of HDPE or LDPE geomembrane. The lower layer is called the “secondary” geomembrane and the upper layer is called the “primary” geomembrane.