Nipissing

Introduction

The Nipissing Property is located in Lorrain Township approximately 16 km southeast of Cobalt, Ontario. It consists of 4 claim units located in Lorrain Township and within the Larder Lake Mining Division of Ontario.  The Nipissing Propety is 100% owned by Atacama.

Geology

The Cobalt Camp and area lay within the Cobalt Embayment, a significant geological structure referred to as an inferred basin, is known to host significant base and precious metal deposits throughout. This project area is along the margin between the southern and superior structural provinces of the Canadian Shield.

There are 3 main regional fault structures trending northwest within the area. They
are the Montreal River, Lake Temiskaming and Cross Lake faults. Numerous secondary and subsidiary faulting is noted throughout the area. The extensive tectonic activity locally is considered chiefly responsible for regional and local metamorphism in association with successive intrusion events.

The basement rock consists mainly of early Precambrian metavolcanics and metasediments such as massive andesitic and basaltic lavas, pillow lavas, pyroclastic and erosional sediments and diabase intrusives. Intrusives of granite, syenite and lamprophyre are noted as dikes and dike swarms.

The Archean age basement is unconformably overlain by huronian supergroup sediments and clastic rocks. The predominant rock of this type is the Cobalt Group featuring mostly Lower Coleman Member and Lorrain Formation. These rocks are all intruded by Nippissing Age diabase dykes and sills and by the Algoman granite
batholith in Lorrain Twp.

The relatively flat lying sill has produced a large basin like structure that has rafted up a portion of the basement rock in the central portion of the map area (Lovell and DeGrijs,1976) and has also rafted and separated a large area of syenite believed to be connected at one time. All rock types are exposed at surface as are sections of the relevant contacts throughout the area.

The majority of the outcrop exposures within the Nipissing Property consist of mafic to intermediate metavolcanic rocks in the form of massive and pillowed basalts and andesites. Located on a small intrusion of mafic volcanic rock within the Nipissing Property, is a mine shaft that has been sunk into a diorite outcrop hosting quartz, sulphide mineralization and magnetite.

History

Newspaper articles in the July 26, 1906 issue of The Montreal Gazette and the November 12, 1906 issue of The Montreal Herald state a settler found a large, slightly yellow diamond about the size of a hen’s egg. Historically this has been called the Nipissing Diamond. At that time M.P. Mr. A. O. Aubin purchased this stone. Also, in 1906, the Tiffany Diamond Firm launched an expedition of geologists and diamond experts to the area to identify the source of the Nipissing Diamond. The August 1, 1906 the Jewelers Circular Weakly quotes the Reverend Father Paradis stating “I myself have seen the stone. It is as large as a hen’s egg and has a rough surface and a yellowish tinge”. The sketch shown above was drawn by Father Paradis.

Figure 2: Nipissing Diamond found in the Cobalt area but exact location unknown.

 

Fred Giroux
1916
Sank a 50 foot shaft with 24 feet of drifting.

Unknown
1949
3 diamond drill holes reported

Cabo Mining Corp.
2000-2010
11 diamond drill holes reported totalling 898 meters
Stripping and trenching
Geological Mapping
Till Sampling
UTM survey
Magnetometer Survey
VLF Survey
Diamond analysis and Kimberlite indicator mineral analysis

Prairie C Resources Development
2001
Prospecting and stripping

Atacama (CXS)
2017
Prospecting and Sampling

 

Figure 3: Past Work on the property.

 

Results of Previous Work

Gossan Zone

A Wilson (2017) reported surface

Silver assays

19.79 oz/ton/1 foot

1.24 oz/ton/0.8 foot

12.48 oz/ton/4 feet

Gold Assays

0.03 oz/ton to 0.085 (grab samples)

Up to 0.374 oz/ton (grab sample)

Diamond drilling results

86.1 oz/ton/0.85 foot Silver

11.53 oz/ton/0.2 foot Silver

2.63 oz/ton/1 foot Gold

0.02 oz/ton/0.3 foot to 11.19 oz/ton/0.5 foot Gold

Figure 4: Gossan Showing

 

Giroux Shaft Area

The surface silver showing is in a vein two feet wide that was blasted out with the first round and occasionally in the shaft sinking, silver was found in small quantities.  The best silver assay from drill core was 0.04 oz/ton over 0.1 meter. A high grade silver cobalt vein 3 meters long and 25 cm wide was found in the vicinity of the shaft. In a pit about 270 meters northeast of the shaft, niccolite (nickel mineral) is reported to have been found.  Surface drilling produced assays up to 577 g/t silver over 0.06 meters.

Figure 5: Sample taken near Giroux Shaft contains 23.3 g/t silver and 1.22% Cobalt

 

Cabo Diamond Showing

In 2002 Cabo Mining Corp reported a diamond discovery on the Nipissing claims.

The Ontario Geological Survey reported: “Cabo Mining Corp. recently recovered diamonds from drill core obtained from a drill program on its Cobalt area property. A 9.3 kg sample taken from diamond drill hole CC-14, processed by caustic fusion, contained a total of 95 diamonds including 4 macrodiamonds (greater than 0.5 mm in two dimensions). The largest diamond recovered was a 2.64 mg white, polytetrahedroid measuring 1.36 mm x 1.20 mm x 1.12 mm. The diamond-bearing sample was taken from a 4.15 m interval (between 32.45 m and 36.60 m) within a 61.0 m intersection of a lamprophyre and mafic, heterolithic breccia zone. Lamprophyre occurs in the heterolithic volcanic breccia as fragments, matrix and as distinct dykes and is best described as lamprophyric diatreme. Although petrographic studies of the Cobalt area heterolithic breccia are at a very early stage, the host rocks appear similar in appearance, age and geological setting to the diamond-bearing lamprophyres and heterolithic volcanic breccias currently being explored 400 km to the west, near Wawa. Outcrop in the area drilled includes several distinct phases of xenolith-bearing dykes, one of which contained three micro-diamond chips from limited surface sampling carried out and reported in 2000. A trenching, stripping and channel sampling program completed in the immediate area of the diamond discovery drill hole returned two micro diamonds.“

Figure 6: Image of Cabo Diamond described above