Following successful tubbing trial assemblies at our Woosung site on Nov.09^th~Dec.1^st 2023, we continue to utilise the following process, which we perfected for assembling 3 tubbing rings to ensure the geometric dimensions required by our project specification for the Woodman Mining Project, prior to bulk manufacture:
As a check on the casting, machining of bolt holes and interchangeability, the following trial is carried out:

a) Assemble and bolt together on a flat level base, segments to form three rings.
b) The rings are built one above the other with the radial joints staggered by approximately half a segment as shown on Contract Drawings.
c) The segments are bolted together with all bolts, washers, lead seals, and gaskets installed and torqued to the design value stated. The test gasket dimensions must be in accordance with those specified on Contract Drawings.

The lowest ring is maintained as the master ring for the duration of the project. The segments forming this ring are hand-picked so that the upper circle flanges form a true plane. The segments for the other two rings shall be picked at random, or by the Project Manager. As an alternative to the master ring, the Supplier may provide a permanent jig or assembly plate, the top surface of which complies with the tolerances of the master ring. This test area is to remain clean, tidy, and clearly identified for the duration of the tubbing manufacturing.

A minimum of four (4) washer load cells (two vertical, two horizontal) are installed and used to monitor/validate the torque-tension relationship over a 24-hour period. The test may be conducted at the project site by the Project Manager and the Shaft Contractor. The results can also inform any changes requested in the torque sequence or timing of torque during construction.

If the torque-tension testing is not carried out on segments within the fully erected test rings (inclusive of lead gaskets and seals), a specific torque-tension testing procedure is to be proposed by the Supplier for approval by the Project Manager and the Engineer. The assembly should match the geometry and conditions specified at typical segment to segment horizontal and vertical joints, inclusive of all steel washers, lead seals and lead gaskets.
From time to time, it may be requested that segments are built to form rings on the master ring to ensure tolerances, and interchangeability of segments is being maintained.

The trial assembly will demonstrate that the fabrication and erection tolerances specified in this Specification are achieved. Use of a 3D laser scanning measurement system is required. Trial assembly will use final installation bolts.