Property, Plant and Equipment

12 Months Ended

Sep. 30, 2022

Property, Plant and Equipment [Abstract]

Property, plant and equipment at September 30, 2022 and 2021 consisted of the following (in thousands):


	September 30,
	2022		2021
Construction equipment	$	402,581	$	333,966
Plants	167,625		143,172
Land and improvements	59,454		53,415
Mineral reserves	91,992		86,556
Buildings	32,566		27,163
Furniture and fixtures	7,110		6,426
Leasehold improvements	1,230		1,230
Total property, plant and equipment, gross	762,558		651,928
Accumulated depreciation, depletion and amortization	(304,935)		(250,803)
Construction in progress	23,789		3,707
Total property, plant and equipment, net	$	481,412	$	404,832

Depreciation, depletion and amortization expense related to property, plant and equipment for the fiscal years ended September 30, 2022, 2021 and 2020 was $68.9 million, $49.5 million and $39.1 million, respectively.

Mineral reserves, net of accumulated depletion, for the years ended September 30, 2022 and 2021 were $87.6 million and $84.1 million, respectively. These amounts include $2.0 million and $2.1 million of asset retirement obligation assets, net of accumulated depletion associated with active mining operations for the years ended September 30, 2022 and 2021, respectively and $3.9 million and $2.7 million of capitalized stripping costs, net of accumulated depletion associated with development stage mining operations for the fiscal years ended September 30, 2022 and 2021, respectively.