SCH Number 2021110076

Project Info

Title

Gem Hill Quarry Project by CalPortland Company (PP21404)

Description

The project proponent has submitted: (a) a Conditional Use Permit (CUP 45, Map 214) application, to allow a surface mining operation and development of a reclamation plan on 82 acres of an approximately 210-acre reclamation plan boundary, which would utilize a 0.75-acre primary access road outside of such reclamation plan boundary to provide access to/from Mojave Tropico Road. Access to the site would be obtained via two access roads to Mojave Tropico Road, specifically the aforementioned access road and a secondary access road to the north thereof. The project proponent proposes to employ open pit, multibench, and drill and blast mining techniques to mine naturally occurring pozzolan (volcanic tuff), which is used in the production of cement. No crushing or processing of mined mined material would occur onsite. The life of the operation is proposed to be 30 years. Annual mineral production is estimated to be 500,000 tons, and the maximum total mineral production is estimated to be 15,000,000 million tons. The total anticipated production of mine waste (overburden) is estimated to be 600,000 tons, which would be disposed in two onsite overburden stockpiles. The proposed maximum depth of excavation is 300 feet below original grade. No phasing of mining is proposed. Maximum operational inter-bench slopes (also referred to as bench face slopes) for the quarry will be 0.25:1 (horizontal:vertical (H:V)) with overall slopes of 1:1 (H:V). Maximum final reclaimed inter-bench slopes for the quarry will be 0.25:1 (H:V). Overall final reclaimed slopes for the quarry will be a maximum of 1:1 (H:V). Maximum operational slopes for the overburden stockpiles will be 1.5:1 (H:V). Maximum and overall final reclaimed slopes for the overburden stockpiles will be 2:1 (H:V). Operations would typically be conducted between 7:00 a.m. and 7:00 p.m., Monday through Saturday, with the understanding that additional shifts or longer/alternative hours may be required due to operational constraints. As proposed, there would be a maximum of 20 employees onsite at any one time. These 20 employees would include haul truck drivers, who would haul overburden onsite (from the quarry to the overburden stockpiles), as well as hauling naturally occurring pozzolan (volcanic tuff) offsite to clients.

6 documents in project