With historic drilling results including 1m at 530g/t gold at a depth of 50m in the Lord Nelson pit, Alto Metals executive director Dermot Ryan is understandably excited about the potential at the Sandstone gold project.

Alto Metals completed its acquisition of Sandstone Exploration in June and has wasted no time in assessing historic data, or as Ryan describes it, “putting Humpty Dumpty back together again”.

Alto staff are creating 3D models of the numerous drilling results in the vast tenement area, based on publicly available information from the WA Department of Mines and Petroleum and ASX announcements by previous owners Troy Resources and Herald Resources.

The Sandstone tenement package covers 723sqkm in the well-endowed Murchison goldfield, which has produced more than 1 million ounces of gold.

Ryan said the volume of information, which included  JORC 2004 compliant resources, indicated there was both plenty of high-grade gold left beneath existing mined oxide pits, as well as further potential in brownfields areas including the Indomitable prospect area. 

“The numbers will blow your socks off,” he says.

His office is filled with newly-created, dining table-sized maps and charts plotting the historic stellar drilling results.

Grades of +15g/t gold are common, and there are hits of between 36g/t and 82g/t lying below the Lord Nelson pit.

“Most junior companies just don’t have these grades to start with,” Ryan notes.

The company’s focus on the gold project prompted a name change in May from Enterprise Uranium Ltd, which had been spun out of Enterprise Metals.

Alto still holds a number of uranium projects but is turning its full attention to Sandstone – a move that has been strongly supported in the market.

It completed an AUD$1 million dollar capital raising in June and welcomed Terry Wheeler, through his company Windsong Valley, as the company’s number one shareholder. Wheeler is well-known in the mining industry and worked for Western Mining Corporation before establishing Genalysis Laboratory Services in 1975, which he eventually sold to Intertek Group.

Alto is a tightly held stock – the top 20 shareholders held 77.31% in early July.

A shareholder purchase plan (SPP) is currently underway to raise A$1.7 million to progress Sandstone. 

Ryan believes the Lord Nelson and Lord Henry bodies are high co-efficient of variation deposits, where very high grade quartz veins lie within a lower grade mineralised envelope.

He said the previous owners had mined the shallow oxide material but the mill, which is on a separate smaller lease acquired by Middle Island Resources, was not designed to handle hard fresh rock.

“Lord Nelson was mined by Troy to about 60m depth, and drilling indicates that the shear zones containing high-grade gold in pyritic quartz veins are open at depth,” Ryan said.

“Troy mined 1.45 million tonnes at 4.43g/t gold for 207,440oz, and the grade was 45% higher than their resource estimate.

Lord Nelson is just one of the highly prospective areas in the tenements and its remaining high grades are making it a top priority for Alto.

“At Lord Nelson along the vein, there are hits of 15g/t, 17g/t, and another 20m along there’s 114g/t and 95g/t in the pit wall, and these figures aren’t isolated,” Ryan said.

“I believe the low-grade mineralisation (that was mined in the pit together with the very high grade veins) are alteration zones, and we need to target these alteration zones below the pit to locate the very high grade veins down dip.”

Ryan says it is a similar case at the nearby Lord Henry pit which was only mined to a depth of about 40m.

“And at the Bulchina deposit, the bottom of the pit has a relatively narrow 4-5m wide trench with a quartz vein containing high grades but they stopped mining at the base of oxidation because they couldn’t process the hard rock,” he said.

“Lord Henry and Lord Nelson were blind deposits and they were discovered during drilling.

“I think there is the potential to find other blind deposits under overburden.”

He sees a strong similarity between the planar structurally controlled shear zones at Lord Nelson and the shear zones hosting high grade gold at Jundee Deeps.

“I worked at Jundee in the 1990s and we mined several hundred thousand ounces of gold from the oxide pits, but when we drilled deeper below the depletion zone, we found several million ounces within high-grade shear zones,” he said.

Jundee is still producing gold from its underground operations for new owner Northern Star Resources.

Ryan was general manager of exploration for Great Central Mines/Normandy Yandal Operations for five years to 2001, and has over 39 years’ experience in the discovery and successful evaluation of gold, base metals, iron ore, diamond and uranium deposits.

Based on his experience, he is also excited by the large-scale oxide gold potential at the Indomitable, Piper,Tiger Moth and Musketeer exploration targets to the north-west of Lord Nelson. 

“Although the drilling to date is patchy, oxide mineralisation has been discovered over 4km of strike, from Indomitable in the north to Musketeer in the south,” Ryan said.

“The area is very deeply weathered down to 200m depth and could contain multiple vein-hosted deposits like Kalgoorlie’s Super Pit.

At the time of going to press, Alto was still compiling the historic information to create one contiguous database for the Sandstone project.

“We’re using the existing drilling data and establishing targets along strike and down dip,” Ryan said.

“Previous explorers undertook some induced polarisation surveys and there are interesting anomalies indicative of deeper sulphide mineralisation along the Lord Henry and Lord Nelson trends that we’ll follow up.

“We’re going to do careful drilling: I see myself more as a sniper than a machine-gunner, there’s no point doing a series of ‘drill and hope’ holes.”

Having said that, Ryan said the exploration program being planned would not hold back.

“Once the approvals are in place, you can expect to see multiple drill rigs at this project,” he said.

“I used to work for Great Central Mines and I’m not afraid to drill.”

Alto will work to establish new JORC 2012 resource estimates based on the remaining ore in the Sandstone pits and establish its exploration program, targeting extensions of known resources and other prospects. 

“It’s very exciting times,” Ryan said.

“We have a great exploration opportunity and I’m enthusiastic because we’ve got high grade gold, and continuity and numerous drilling targets.”