Property, Plant and Equipment

12 Months Ended

Sep. 30, 2021

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

Property, plant and equipment at September 30, 2021 and 2020 consisted of the following (in thousands):

	September 30,
	2021		2020
Construction equipment	$	333,966	$	253,157
Plants	143,172		102,392
Land and improvements	53,415		38,647
Mineral reserves	86,556		22,205
Buildings	27,163		18,307
Furniture and fixtures	6,426		5,648
Leasehold improvements	1,230		1,135
Total property, plant and equipment, gross	651,928		441,491
Accumulated depreciation, depletion and amortization	(250,803)		(209,532)
Construction in progress	3,707		5,271
Total property, plant and equipment, net	$	404,832	$	237,230

Depreciation, depletion and amortization expense related to property, plant and equipment for the fiscal years ended September 30, 2021, 2020 and 2019 was $49.5 million, $39.1 million and $30.1 million, respectively.

Mineral reserves, net of accumulated depletion, for the years ended September 30, 2021 and 2020 were $84.1 million and $20.3 million, respectively. These amounts include $2.1 million and $0.0 million of asset retirement obligation assets, net of accumulated depletion associated with active mining operations for the years ended September 30, 2021 and 2020, respectively and $2.7 million and $0.0 million of capitalized stripping costs, net of accumulated depletion associated with development stage mining operations for the fiscal years ended September 30, 2021 and 2020, respectively.