The O’Donnell occurrence is located immediately south of the Salmo River to the northeast of the historic Reeves MacDonald mine, approximately 25 kilometres south of Trail.

The zinc-lead-silver-cadmium mineralization is hosted by dolomitized limestones of the Reeves Member of the Lower Cambrian Laib Formation. This limestone trends generally east-northeast, dips south at a high angle and is overlain to the southeast by black phyllites and argillites of the Emerald Member of the Laib Formation. To the northwest, it is underlain by phyllites of the Truman Member, also of the Laib Formation, which are in turn underlain by quartzites of the Hadrynian–Lower Cambrian Reno and Quartzite Range formations (Hamill Group).

The Reeves Limestone is black and white banded, weathers to a blue-grey and hosts irregular zones of light grey dolomitic alteration, which weathers buff. Poor exposures make it difficult to identify the full extent of the dolomitization but the main showing alteration is in the order of 30 to 50 metres thick and terminates against a northwest-trending northeast-dipping transverse fault approximately 300 metres southwest of Portal 1. The dolomite thins to the northeast to less than 30 metres. Zones of dolomitization have also been identified at various stratigraphic levels in the Reeves Limestone along Red Bird and Harcourt creeks. South and west of Red Bird Creek, the Reeves Limestone and associated stratigraphy is masked by an east to west overthrust wedge of Lower and Middle Ordovician Active Formation argillites in the order of 600 metres thick.

The O'Donnell orebody is a Kootenay Arc–type sedimentary exhalative deposit situated within a dolomitized envelope of the Reeves Member Limestone of the Lower Cambrian Laib Formation. The O'Donnell orebody, along with the Reeves, B.L. and No. 4 orebodies, which together make up the Reeves MacDonald mine (MINFILE 082FSW026), are all fault-displaced segments of a single ore zone located on the axis of the Reeves syncline. The Reeves syncline is developed as a secondary fold on the south limb of the Salmo River anticline. Refer to the Reeves MacDonald for a summary of area geology and for production statistics, which include O'Donnell ore.

The O'Donnell orebody, exposed in the O'Donnell adit, is enveloped by dolomite and seems to have a shape and plunge comparable to the Reeves orebody, although the barren limestone between the dolomite halo and the Truman Member (Laib Formation) phyllites is thinner than it is to the west. The Reeves orebody is in the form of an attenuated syncline with limbs striking west and plunging parallel to the axis of the Reeves syncline.

Sulphides in the Reeves MacDonald orebodies occur as well-laminated bands and lenses and as disseminated pyrite, honey-coloured sphalerite and galena in a medium to dark grey banded dolomite. Laminations are generally discontinuous and locally highly contorted. Commonly the ore is brecciated, particularly on the synclinal limbs, and the breccias contain rounded to angular, rotated fragments of dolomite and limestone in a sulphide matrix. Breccias are usually rich in pyrite. Locally, copper can be approximately 0.5 per cent and cadmium is in the order of less than 1 gram per tonne, based on production records from 1949 to 1971. Minor gallium and germanium have been reported from grab samples. The ore is cut by narrow veinlets of coarsely crystalline, white calcite, dolomite and quartz with minor sphalerite and galena.

In the Reeves MacDonald mine, the O’Donnell zone was developed from a 2350 level adit and from the 1900 level workings below.

The original Reeves MacDonald claims, then referred to as the Drumlummon group of claims, were staked to the east of the Pend d’Oreille River between 1910 and 1912 by J.H. MacDonald and J. Quayle of Rossland. At approximately the same time, R.M. Reeves staked the International Lead group of showings, located approximately 1200 metres to the northeast. In 1923, the MacDonald property was reported on under the name "Rio Tinto"; the seven claims were bonded by L.P. Larson and associates of Metalline, Washington.

The Victoria Syndicate, Limited, of London, England, optioned the International Lead and Drumlummon groups in 1925 and began initial development work on what would become the Reeves MacDonald mine. Exploration and development work continued into 1927 and included approximately 457 metres of openings in the MacDonald adit, located approximately 18 metres above the Pend d'Oreille River, and more than 610 metres of openings in the Reeves adit, located 1219 metres to the northeast. Diamond drilling during this period totalled approximately 3048 metres. Five promising ore zones were indicated.

Reeves MacDonald Mines Limited was incorporated in 1928, with Pend d'Oreille Mines & Metals Company of Spokane, Washington, holding a controlling interest; the Victoria Syndicate retained a small interest in the new company. In 1929, the 1900 level was driven to intersect the Reeves orebody. By 1929, the Point, Reeves, MacDonald, O’Donnell and Prospect orebodies had all been explored. Development operations were suspended in 1930. The Drumlumin (Lot 12076) and International Lead No. I (Lot 12692) claims, along with the Annex and River claims on the western side of the Pend d’Oreille River, were Crown-granted to the company in 1931. Further crosscutting and diamond drilling was completed in the 1900 level between 1937 and 1938. Major construction began on the mine in 1947. In August 1949, a 450-tonne per day (500-ton per day) concentrator was installed and put into operation; the following year, concentrator capacity was increased to 885 tonnes per day (900 tons per day). The mineral deposits were accessed by an underground series of adits, raises and internal shafts over a vertical span of 1000 metres. The mine was developed from the 2438-metre-long 1900 level main haulage and on the upper 2650 level. The two levels are connected by an internal 55-degree shaft. Two internal inclined shafts extend from the 1900 to the 1100 level. Development work was carried to the 17-metre level, 562 metres below the 1900 level. The B.L. and O'Donnell orebodies were developed from separate openings established at the 2350 level. With the exception of a two-year closure from 1953 to 1955 due to a decline in metal prices, operations were continuous until July 1971, when the known ore reserves on the east side of the Pend d’Oreille River were mostly depleted and the Reeves MacDonald mine was shut down. Some salvage mining was completed between 1972 and 1974. In 1974, lateral development work and raising totalled 252 metres.

Exploration of the Annex claims on the west side of the Pend d’Oreille River began in 1966, leading to the discovery of the Annex mineralized zone. Exploration of the claims consisted of surface diamond drilling. Mineralization encountered during drilling was explored from an adit at the 533-metre level, which was advanced 511 metres in 1967. Exploratory drifting and diamond drilling were carried on through 1968. Sinking of a 305-metre (1001-foot) shaft began in 1968. Preliminary development on the Annex mine began in 1969 and production began in April 1970.

The Annex mineralization was accessed by adit and internal shaft and mined over a vertical height of 185 metres. Reeves MacDonald Mines Limited obtained a lease-option agreement from Hecla Mining in 1973 and began an exploration program in the Red Bird area to test for the projected westerly extension of the Annex zone. Reeves MacDonald Mines advanced the 800 level drift, the lowest drift in the Annex mine, approximately 213 metres (700 feet) west onto the Red Bird property. Within the drift, 15 diamond drill holes totalling 1890 metres (6200 feet) were completed to find the offset sulphide zone. Four drillholes intersected four 6.5-metre-wide bands of zinc mineralization averaging 4.18 per cent zinc, 0.12 per cent lead, 0.56 ounce per ton silver and 0.04 per cent cadmium (Assessment Report 30001). This work was successful in locating the faulted extension of the Annex zone and the grades encountered were comparable to the ore mined in the Reeves MacDonald mine. In 1974, approximately 65 metres of crosscutting and drifting and 1038 metres of diamond drilling were completed as part of the development program. Approximately 1673 tonnes (1700 tons) of development ore were milled, but further development was deferred due to the marginal character of the ore (Hecla Operating Company, 1974 Annual Report) and the inability of Reeves MacDonald Mines and Hecla Mining to reach a suitable business agreement. No further development on the Red Bird extension was completed before the Annex mine closed in 1975. Most of the ore mined from the Annex mine during 1973 and 1974 came from the 1250 West zone. Development of the 240 K zone, which lies east of the Annex, was in progress in 1973. Probable reserves in this zone were estimated at approximately 272 155 tonnes (300 000 tons; Reeves 1973 Annual Report). The mine closed in April 1975.

The Red Bird group of claims, to the immediate northwest of the Annex zone and including the Red Bird, Lead Pot and Lead Cup claims, was owned by S. Coulter and A.J. Campbell of Ymir in 1924. The claims were staked to cover several surface exposures of earthy gossan zones along strike with the Reeves MacDonald property to the east. Conrad Wolfe and associates optioned the claims in 1925, incorporated the Red Bird Mining Company of Spokane and staked an additional 17 claims. From 1925 to 1927, more than 305 metres of underground exploration work was completed, though results were disappointing. A Vancouver syndicate acquired a controlling interest in Red Bird Mining Company and, in 1928, extended the lower adit several hundred metres and carried out a small amount of diamond drilling. In February 1929, the syndicate incorporated Boundary Basin Mines Limited Workings, though no work was reported by the company. Workings at that time comprised a lower adit approximately 366 metres long and, at higher elevations, two short adits, an 11-metre shaft and several open cuts. Sixteen claims and fractions, including the Lead Cup (Lot 13466), Lead Pot (Lot 13465) and Red Top (Lot 14148), were Crown-granted to Boundary Basin Mines in 1932 and 1934.

Hecla Mining Company of Wallace, Idaho, purchased the property in 1944. In 1947, Diem Mines Limited, a subsidiary of Hecla Mining Company, conducted geological mapping and minor surface work. Between 1947 and 1960, exploration by Diem Mines consisted of geological mapping, trenching, sampling and diamond drilling, with bulldozer stripping and two diamond drill holes totalling 130 metres completed in 1958. In 1955, J.T. Fyles and C.G. Hewitt of the Geological Survey of Canada mapped the geology and mineralization of the region, though the Red Bird adits had already caved in at the time of mapping. The Consolidated Mining and Smelting Company (Cominco Ltd.) optioned the property in 1961. Between 1961 and 1962, the 2650 level adit was extended an additional 244 metres (800 feet) and 12 diamond drill holes totalling 1250 metres were completed on the main Red Bird showing. Strong and apparently continuous oxidized zinc-lead mineralization was encountered, including one approximately 6-metre-wide (20-foot-wide), 183-metre (600-foot) length along the drift that averaged 18.5 per cent zinc and 6.5 per cent lead (Assessment Report 30001); however, no sulphides were encountered and the property was returned to Hecla Mining.

In 1985, Golden Eye Minerals Limited acquired an option on an 80 per cent interest in the Red Bird property from Diem Mines Limited. At the same time, Golden Eye Minerals also optioned the Nor claims and staked the Tic claims to the west of the Red Bird property. From 1985 to 1986, Teck Corporation optioned the property from Golden Eye Minerals. During this time, Teck completed six surface diamond drill holes totalling 2691 metres to test the downdip extension of the Red Bird showing. Three of the holes had to be abandoned: One drillhole encountered zinc mineralization in an unexpected formation overlying the Reeves Limestone; another hole intersected the anticipated target and encountered highly oxidized mineralization with very poor core recovery at a vertical depth of 457 metres (1500 feet). Between 1986 and 1988, Golden Eye Minerals drilled eight surface diamond drill holes totalling 4914 metres (16 122 feet) to test the downplunge continuity of the Red Bird zone and the faulted offsets of the Annex–Annex West zones. Drilling confirmed the continuity of the orebodies at depth and several drillholes intercepted significant rock of ore grade.

In 1991, Golden Eye Minerals became Annex Exploration Corporation. Exploration continued that year with a reconnaissance soil and silt sampling program, geological mapping and a bulk sampling program on the oxidized Red Bird deposit. A 100-kilogram bulk sample of limonite was extracted from the Beer Bottle showing and returned results of 2 per cent carbonate, 40 per cent limonite and 50 per cent hemimorphite (a hydrated zinc silicate containing 67.5 per cent zinc). The company commissioned J. Hams, Ph.D., to complete a mineralogical study of the oxidized material and BC Research and Fluor Daniel Wright Limited engineering consultants to conduct technical research into the feasibility of leaching and solvent extraction of leachable zinc from the oxide material exposed at the surface above the Red Bird workings. Fluor Daniel Wright Limited was also commissioned to study the cost of reaccessing the Annex mine and performing underground exploration on the Red Bird property. D.S. Jennings, Ph.D., was also commissioned to provide a review of previous exploration programs, the results of those programs and the implications for further work on the property.

In 1993, Annex Exploration purchased the Red Bird property from Acadia Mines Limited (formerly known as Diem Mines Limited) and, in 1994, Annex Exploration became Redhawk Resources Incorporated. Between 1995 and 1998, Redhawk Resources Inc. consolidated Red Bird and other properties under the ReMac project name and acquired additional claims in the area. In 1998, Annex Exploration conducted a limited exploration program involving trenching at surface oxide showings and the use of directional drilling methods to locate the core of the Annex mineralization. Drilling consisted of one NQ- and HQ-size diamond drill hole totalling 1467 metres (Drillhole 98-1) and two directional cuts (Drillholes 87-1A and 98-1A). Drillhole 98-1 intersected a 12.93-metre-wide section of Annex-type mineralization within the Reeves Limestone approximately 415 metres below the 800 level adit. Directional cut 98-1A was wedged at 832 metres depth in Drillhole 98-1 and intersected a 10.91-metre-wide section grading 4.75 per cent zinc (Assessment Report 30001). Directional cut 87-1A was wedged at 743 metres depth in Drillhole 87-1 and intersected a mineralized zone within the Reeves Limestone. Two drillholes were completed on the Caviar No. 5 claim south of the Red Bird showing and results of this drilling extended the Annex system an additional 200 metres to a total of 365 metres of downplunge continuity.

Redhawk optioned the Reeves MacDonald Mine property (MINFILE 082FSW026) in April 2000 and included it within the ReMac project area. Historic MINFILEs occurring within the ReMac property included Red Bird (MINFILE 082FSW024), Reeves MacDonald (MINFILE 082FSW026), Point (MINFILE 082FSW027), Prospect (MINFILE 082FSW029) and Annex (MINFILE 082FSW219). Shortly after, ZincOx Resources B.V. was granted an option on the property. That year, Redhawk and ZincOx Resources conducted an exploration program consisting of drilling and trenching on the oxide zone located on the Red Bird and Reeves claim groups. Five oxide zones were tested with 21 reverse circulation drill holes totalling 2600 metres, and three zones were trenched. Samples collected during exploration were sent for metallurgical testing. The extensive, overlying zinc oxide capping was not mined due to the lack of extraction technology at the time. The zinc oxide deposits occurred over 3 kilometres, extended from the surface to a depth of up to 450 metres and contained zinc grades comparable to those of the primary sulphides. Highlights of the program included Hole R-2000-02 (zone B), which assayed 15.43 per cent zinc and 1.55 per cent lead over 5.3 metres, and Hole R-2000-09 (zone C), which assayed 8.68 per cent zinc and 4.27 per cent lead over 12.2 metres. Results from the drilling and trenching proved the predicted model of large, coherent elongated zones of zinc mineralization repeated predictably by a series of normal faults and confirmed the potential of the property for large zones of zinc oxide mineralization. ZincOx Resources withdrew from the project at the end of 2000 and no further work was completed until 2004.

In 2004, Redhawk Resources drilled eight BTW-size drillholes totalling 346.3 metres in the western portion of the property. One hole intersected the Reeves Limestone at 44.8 metres below the surface, indicating potential for relatively shallow zinc-lead deposits in this region of the property. Exploration continued in 2005 with a program of soil sampling and geological mapping. Redhawk Resources contracted Wardrop Engineering Incorporated to conduct a National Instrument 43-101 compliant review of the geology, exploration history and historic estimates from all reports generated since 1998 on the property. The National Instrument 43-101 technical report was released in February 2007.

In 2006, Redhawk Resources sold the ReMac zinc project to its wholly owned subsidiary, ReMac Zinc Corporation. In 2007, OMC Capital Corporation purchased the ReMac Zinc Corporation, renaming it ReMac Zinc Development Corporation and changing its own name to ReMac Zinc Corporation. That same year, ReMac Zinc Development Corporation conducted a drilling program targeting the Reeves Limestone. In total, 6189.6 metres of HQ- and NQ-size drilling were completed on three cell claims. Results of the drilling provided an on-strike extension of the mineralization-bearing limestone unit several kilometres to the west of the known mineralized zones, approximately doubling the known strike length of the Reeves Limestone on the ReMac property. The mineralization encountered was similar to that found in the Reeves MacDonald mine. Additional work included the production of detailed air photos and the creation of a new topographic base map. Metallurgical work was completed on a bulk sample of Red Bird oxide to determine zinc recovery. A baseline data collection program was also started to support permitting requirements for future mine development.

Significant results from the 2000 drilling program include 2.3 metres of 23.75 per cent zinc and 174.8 grams per tonne silver, 2.7 metres of 18.94 per cent zinc, 0.27 per cent lead and 14.7 grams per tonne silver, and 3.9 metres of 18.47 per cent zinc, 1.80 per cent lead and 31.8 grams per tonne silver (Assessment Report 26478). Drillhole 2004-A5, drilled during the 2004 exploration program, intersected a 4.3-metre section grading 15.11 per cent lead and 1.85 per cent zinc at the base of the hole (Assessment Report 27849). In 2007, Drillhole 07-12 encountered the widest intersection of high-grade material, with 2 metres of 0.7 per cent zinc within 58 metres averaging 0.6 per cent zinc and occurring within a dolomite altered zone of the Reeves Limestone (Assessment Report 30001).