The ESM property contains 14 known zones of zinc mineralization. The deposits tend to occur in clusters. Three clusters have been defined consisting of three to five deposits each. Geometry of mineralization varies, ranging from tabular to podiform, shallow to steep. Areas defined to date contain tonnages ranging from roughly 0.5 Mt to over 10 Mt. Typical thickness ranges from 2 ft. to 12 ft. thick. Mineralization tends to be very continuous along strike, ranging from 50 ft. to 800 ft. Plunge-lengths may exceed 6,000 ft.

Massive sphalerite-bearing zones are stratiform, and semi-massive zones are crosscutting and stratabound. ESM geologists conceptualize a parent-daughter relationship, where the stratiform mineralization is the parent and the crosscutting zone is the daughter. The parent-daughter model suggests that daughters are formed from sphalerite remobilized from parents during metamorphism. The sphalerite migrates along fault surfaces up and down dip from the parents, potentially as far as the Unit 10 anhydrite. It is thought that ductile flow of Unit 10 anhydrite closes fault surfaces and halts migration of remobilized sphalerite. Daughter zones share similar trace element geochemical signatures with their parent zones. They often contain significant quantities of occluded wall rock material. The geologists have experienced exploration success using the parent-daughter model, defining four new zones in the 1990’s.

The mineralization at ESM has been classified as sedimentary exhalative (Sedex) in origin. The composition of the mineralization is unique, composed of primarily massive sphalerite and only minor galena and pyrite. The zinc-lead ratio is approximately 35:1. ESM has slightly higher-than-average grade for a sediment-hosted lead-zinc deposit. Typical grades of sediment-hosted lead- zinc deposits may average 7.9% Pb and Zn combined. The average grade was 8.6% Zn, while the average for the greater Balmat-Edwards zinc district is even higher at 9.4% Zn. Some ESM geologists have theorized that intense metamorphism may have concentrated the sphalerite, perhaps fractionating zinc sulphide (sphalerite) from lead and silver sulphide (galena) and remobilizing them to different locations leading to the high zinc grades observed at ESM.

The ESM deposit is mined using four underground mining methods, based on the geometry and the grade of the mineralized zones:

- Longhole stoping (“LH”) for mining blocks dipping steeper than 45°, which represents about 50% of the mine plan tonnage. This is the preferred mining method from a productivity and operating cost perspective;

- Mechanized Cut and Fill (“C&F”), for mining blocks with dips of less than 45° and zones not amenable to LH stoping, is more selective and represents about 7% of the mine plan tonnage;

- Modified or Stepped Room and Pillar (“RP”), for mining blocks with dips of less than 45° and grades, do not warrant the application of a fill to permit multiple panel extraction, representing 11% of the mine plan tonnage;

- Sub-level drift slashing and pillar slashing (“SLS”) for mining blocks which require lateral extension from the sub-level drift to either accommodate LH drills to drill LH stopes, or to recuperate remnant pillars left between rooms in the existing workings, representing 19% of the mine plan tonnage; and

- The remaining 13% of the mine plan tonnage comes from sub-level drives, access, and stope cross-cut development.

Un-cemented rock fill is used as backfill to maximize mining recovery. Where availability of fill material is not present, structural pillars are left within the mineralization. Approximately 8% of the mineralization targeted for extraction are left behind as pillars.

The deposit is accessed from the existing No. 4 shaft and level development, which is extensive. On shaft levels, access ramps have been driven at maximum grade of 15% at a 15 ft. x 17.5 ft. profile to accommodate 40-ton haul trucks.

Level spacing is variable up to a maximum of 70 ft. Mineralized zone development is driven using a 13 ft. x 13 ft. profile.

The mine has undergone drift rehabilitation and utility refurbishments, as well as mobile equipment servicing. These activities commenced in March 2017, shortly after St. Lawrence Zinc was purchased by Titan Mining. A further 46,000 ft. of drift refurbishment is required as part of the mine plan to re-open several mining zones.

The mine design was based on basic assumptions to generate lower limits for cut-off grades (“COG”) for the planned mining methods. A value of 6.0% Zinc (“Zn”) was determined as the COG for mining. These COGs were used to design mining shapes. An incremental COG of 2.0% Zn.

Mineralized material mined from the ESM deposits are processed at the existing concentrator that was commissioned in 1970 and last shut down in 2008. The existing plant flotation circuit consists of a lead flotation circuit followed by zinc flotation. Lead grades for the mill feed material are less than 1%, and as such, a lead concentrate is not produced.

The concentrator flowsheet includes crushing, grinding, sequential lead and zinc flotation circuits, concentrate dewatering circuits, and loadout facilities.

The zinc flotation circuit consists of rougher flotation followed by scavenger flotation. The scavenger concentrate returns to the head of the rougher circuit. Rougher concentrate undergoes two stages of cleaner flotation. Cleaner tailings are returned to the previous stage of flotation in the traditional manner.

The nameplate capacity of the concentrator is 5,000 t/d. Through-out the history of the ESM operation, the capacity of the concentrator has exceeded the mines capacity. The traditional operating strategy has been to operate the concentrator at its rated hourly throughput of 200 to 220 tons per hour (“t/h”), but for only as many hours as necessary to suit mine production.

Similar to past operations at ESM, mine production rates are not able to sustain the fulltime use of the concentrator. A single 10-hour shift will operate four days per week to process mill feed at an equivalent operating rate of 5,000 t/d.