Document ID: chunk:federal_register_of_legislation:F2024C00833:reg:22:p23
Version: federal_register_of_legislation:F2024C00833
Segment Type: reg
Provision Reference: reg 22 (pt 23/29)
Character Range: 290217–292893

paragraph (a) or (b) of step 1 applies, identify, for each borehole, the depth of the top of the gas bearing strata at which the first of the 3 consecutive samples in the borehole was taken.
        Note   The depth of the top of the gas bearing strata worked out under step 2 is the same as the depth of the base of the low gas zone.

Method of working out base of low gas zone for subparagraph (1)(d)(i)
 (3) For subparagraph (1)(d)(i), the method is that the estimator must work out the average depth at which step 2 of the method in subsection (2) applies.

Method of working out base of low gas zone for subparagraph (1)(d)(ii)
 (4) For subparagraph (1)(d)(ii), the method is that the estimator must construct a 3‑dimensional model of the surface of the low gas zone using a triangulation algorithm or a gridding algorithm.

3.25B  Further requirements for estimator
 (1) This section applies if:
 (a) the estimator constructs a 3‑dimensional model of the surface of the base of the low gas zone in accordance with the method mentioned in subsection 3.25A(4); and
 (b) the 3‑dimensional model of the surface of the low gas zone is extrapolated beyond the area modelled directly from boreholes in the domain.
 (2) The estimator must:
 (a) ensure that the extrapolated surface:
 (i) applies the same geological modelling rules that were applied in the generation of the surface of the base of the low gas zone from the boreholes; and
 (ii) represents the base of the low gas zone in relation to the geological structures located within the domain; and
 (iii) is generated using a modelling methodology that is consistent with the geological model used to estimate the coal resource; and
 (iv) the geological model used to estimate the coal resource meets the minimum requirements and the standard of quality mentioned in section 1 of the ACARP Guidelines.
 (b) make and retain a record:
 (i) of the data and assumptions incorporated into the generation of the 3‑dimensional surface; and
 (ii) that demonstrates that the delineation of the 3‑dimensional surface complies with sections 1.13 and 3.24.

3.25C  Default gas content for gas bearing strata in low gas zone
  A default gas content of 0.00023 tonnes of carbon dioxide per tonne of gas bearing strata must be assigned to all gas bearing strata located in the low gas zone.

3.25D  Requirements for estimating total gas contained in gas bearing strata
 (1) The total gas contained in gas bearing strata for an open cut coal mine must be estimated in accordance with the emissions estimation process mentioned in section 1 of the ACARP Guidelines.
 (2) The gas distribution model used for estimating emissions must be