cdu vs sfr

Can anyone explain why Sandfire's market cap ($1000M) is double that of Cudeco's ($480M)?

By my analysis they appear to be on par in terms of revenue. They have a higher grade (5%) but only a 1.5Mtpa plant and most of the mine is underground.

From Sandfire's March quarterly :

- Life-of-mine extraction of 10.68Mt of material grading 5.0% Cu, 1.7g/t Au (531,000t copper, 579,000oz gold)
- Production of 60-70,000tpa of payable copper metal and 40-45,000oz pa of gold over initial scheduled mine life of 7+ years
- C1 cash operating costs of US$0.90-$1.00/lb including gold credits
- Pre-tax operating cash flow of A$330-350M per annum (from FY 2012/2013)

Mining method: Open pit (2 years), underground (7+ years)
Construction time: 13 months (commencing June 2011)
First production: Open pit Q1 CY 2012
Underground Q3 CY 2012
Processing rate: 1.5Mtpa
Metallurgical recovery: 91%
Average annual payable metal output:
60-70,000tpa payable copper
40-45,000oz payable gold

Pre-production capital cost estimate:
A$270M (plant and infrastructure)
A$130M (open pit/underground development)
A$400M total (including contingencies)

C1 cash operating costs:
US$0.90-$1.00/lb (including gold credits)

Annual gross sales revenue (average): $550-600M
Annual pre-tax operating net cash flow (average): $330-$350M