TORONTO (miningweekly.com) – The town council of Florence, Arizona, has rescinded an ordinance enacted in August 2012 that had effectively banned the use of large quantities of sulphuric acid by miners and other businesses, which now paves the way for mineral-development firm Curis Resources to move forward with its Florence copper project.

On Monday, a vote by the Florence town council resolved to rescind Town Ordinance No 583 - 12 concerning the use and storage of sulphuric acid within town limits.

"The removal of this ordinance allows the company to continue preparations for the start of construction and operations of the Phase 1 production test facility (PTF), allowing the company to demonstrate the safe operation of in-situ techniques and water safeguards," Curis VP for environment and technical services and GM Dan Johnson said.

He added Curis was awaiting approval from the Environmental Protection Agency (EPA) for an underground injection control permit for the project’s PTF. “We anticipate the EPA will issue the final operating permit for the PTF in the near future,” Johnson said.

On August 6, 2012, the Florence town council enacted Ordinance 583 - 12 declaring "[i]n-situ mining and other businesses which utilize large quantities of sulfuric acid" to be a nuisance and a "nauseous, offensive and unwholesome business".

Under the Ordinance, any person conducting a business, except agriculture, using 50 gallons or more of sulphuric acid within any 30-day period was guilty of a Class 1 misdemeanour; with each day such business operates chargeable as a separate offense. The ordinance included an emergency clause making it immediately effective.

PREFEAS COMPLETE

The Canadian copper junior in February said it had completed a “positive” prefeasibility study (PFS) on its central Arizona property, which placed a pretax net present value (NPV) of $748-million on the project, at a 7.5% discount rate.

Authored by consultants M3 Engineering & Technology, the base-case economics for the flagship Florence copper project used a $2.75/lb long-term copper price and an average design production rate of 55-million pounds of copper a year in the first five years, rising to 85-million pounds in year six.

The base-case economics indicated an internal rate of return (IRR) of 38% and a pretax 2.4-year payback of the $129-million capital costs. This represented an 18% decrease from the initial capital cost estimate in the 2010 preliminary economic assessment. The commercial operating life of the project was also extended from 19 to 25 years.

At a price sensitivity of $3/lb of copper, the pretax NPV increased to $875-million and the project had an IRR of 41%.

The PFS found the mine could produce copper at a life-of-mine cost of 79c/lb.